How does cervical sagittal profile change after the spontaneous compensation of global sagittal imbalance following one- or two-level lumbar fusion.

PURPOSE: This study aimed to evaluate the cervical sagittal profile after the spontaneous compensation of global sagittal imbalance and analyze the associations between the changes in cervical sagittal alignment and spinopelvic parameters. METHODS: In this retrospective radiographic study, we analyzed 90 patients with degenerative lumbar stenosis (DLS) and sagittal imbalance who underwent short lumbar fusion (imbalance group). We used 60 patients with DLS and sagittal balance as the control group (balance group). Patients in the imbalance group were also divided into two groups according to the preoperative PI: low PI group (≤ 50°), high PI group (PI > 50°). We measured the spinal sagittal alignment parameters on the long-cassette standing lateral radiographs of the whole spine. We compared the changes of spinal sagittal parameters between pre-operation and post-operation. We observed the relationships between the changes in cervical profile and spinopelvic parameters. RESULTS: Sagittal vertical axis (SVA) occurred spontaneous compensation (p = 0.000) and significant changes were observed in cervical lordosis (CL) (p = 0.000) and cervical sagittal vertical axis (cSVA) (p = 0.023) after surgery in the imbalance group. However, there were no significant differences in the radiographic parameters from pre-operation to post-operation in the balance group. The variations in CL were correlated with the variations in SVA (R = 0.307, p = 0.041). The variations in cSVA were correlated with the variations in SVA (R=-0.470, p = 0.001). CONCLUSION: Cervical sagittal profile would have compensatory changes after short lumbar fusion. The spontaneous decrease in CL would occur in patients with DLS after the spontaneous compensation of global sagittal imbalance following one- or two-level lumbar fusion. The changes of cervical sagittal profile were related to the extent of the spontaneous compensation of SVA.

Long-term efficacy of Waveflex semi-rigid-dynamic-internal-fixation system in delaying intervertebral disc degeneration at adjacent segments and improving spinal sagittal imbalance.

The Waveflex semi-rigid-dynamic-internal-fixation system shows good short-term effects in the treatment of lumbar degenerative diseases, but there are few long-term follow-up studies, especially for recovery of sagittal balance. Fifty patients with lumbar degenerative diseases treated from January 2016 to October 2017 were retrospectively analysed: 25 patients treated with Waveflex semi-rigid-dynamic-internal-fixation system (Waveflex group) and 25 patients treated with double-segment PLIF (PLIF group). Clinical efficacy was evaluated by Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). Imaging data before surgery and at 3 months, 1 year, and 5 years postoperatively was used for imaging indicator assessment. Local disc degeneration of the cephalic adjacent segment (including disc height index (DHI), intervertebral foramen height (IFH), and range of motion (ROM)) and overall spinal motor function (including lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), and |PI-LL|) were analysed. Regarding clinical efficacy, comparison of VAS and ODI scores between the Waveflex and PLIF groups showed no significant preoperative or postoperative differences. The comparison of the objective imaging indicators showed no significant differences in the DHI, IFH, LL, |PI-LL|, and SS values between the Waveflex and PLIF groups preoperatively and 3 months postoperatively (P > 0.05). These values were significantly different at 1 and 5 years postoperatively (P < 0.05), and the Waveflex group showed better ROM values than those of the PLIF group (P < 0.05). PI values were not significantly different between the groups, but PT showed a significant improvement in the Waveflex group 5 years postoperatively (P < 0.05). The Waveflex semi-rigid dynamic fixation system can effectively reduce the probability of intervertebral disc degeneration in upper adjacent segments. Simultaneously, patients in the Waveflex group showed postoperative improvements in LL, spinal sagittal imbalance, and quality of life.

Change of cervical flexion range of motion influences postoperative sagittal alignment of the cervical spine after laminoplasty.

OBJECTIVE: The relationships between preoperative cervical spine range of motion (ROM) and postoperative cervical sagittal alignment (CSA), and clinical outcomes after laminoplasty (LMP) have been widely studied. However, the impact of ROM changes on postoperative CSA and clinical outcomes after LMP remains unclear. Herein, patients with cervical spondylotic myelopathy (CSM) were retrospectively analyzed to explore the association between postoperative cervical ROM changes and CSA and surgical outcomes. METHODS: Patients who underwent cervical LMP at our hospital between January 2019 to June 2022 were retrospectively reviewed. CSA parameters were measured before the surgery and at the final follow-up. Loss of cervical lordosis (LCL) was defined as preoperative cervical lordosis (CL) - postoperative CL. An increase in the cervical sagittal vertical axis (I-cSVA) was defined as postoperative cervical sagittal vertical axis (cSVA) - preoperative cSVA. We defined the changes in cervical flexion range of motion (△Flex ROM, preoperative Flex ROM minus postoperative Flex ROM) > 10° as L- Flex ROM group, and △Flex ROM ≤ 10° as S- Flex ROM group. Japanese Orthopedic Association (JOA) score and visual analog score (VAS) were used to assess the surgical outcomes. RESULTS: The study comprised 74 patients and the average follow-up period was 31.83 months. CL, total ROM, and Flex ROM decreased and cSVA increased after cervical LMP. LCL and I-cSVA were positively correlated with △Flex. Multiple linear regression analysis showed that a decrease in the Flex ROM was a risk factor for LCL and I-cSVA after LMP. LCL and I-cSVA were higher in the L-Flex ROM group than in the S-Flex ROM group. Postoperative JOA and the JOA recovery rate were worse in the L-Flex ROM group than in the S-Flex ROM group. CONCLUSIONS: Cervical total and Flex ROM decreased after cervical LMP. The reduction of Flex ROM was associated with LCL and I-cSVA after surgery. The preservation of cervical Flex ROM helps maintain CSA after LMP. Therefore, more attention should be paid to maintaining cervical ROM to obtain good CSA and surgical effects after cervical LMP.

Incidence and risk factors of proximal junctional kyphosis in adolescent idiopathic scoliosis after correction surgery: a meta-analysis and systematic review.

AIM: To analyze the risk factors of proximal junctional kyphosis (PJK) after correction surgery in patients with adolescent idiopathic scoliosis (AIS). METHODS: PubMed, Medline, Embase, Cochrane Library, Web of Science, CNKI, and EMCC databases were searched for retrospective studies utilizing all AIS patients with PJK after corrective surgery to collect preoperative, postoperative, and follow-up imaging parameters, including thoracic kyphosis (TK), lumbar lordosis (LL), proximal junctional angle (PJA), the sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), pelvic incidence-lumbar lordosis (PI-LL), sacral slope (SS), rod contour angle (RCA) and upper instrumented vertebra (UIV). RESULTS: Nineteen retrospective studies were included in this meta-analysis, including 550 patients in the intervention group and 3456 patients in the control group. Overall, sex (OR 1.40, 95% CI (1.08, 1.83), P = 0.01), larger preoperative TK (WMD 6.82, 95% CI (5.48, 8.16), P < 0.00001), larger follow-up TK (WMD 8.96, 95% CI (5.62, 12.30), P < 0.00001), larger postoperative LL (WMD 2.31, 95% CI (0.91, 3.71), P = 0.001), larger follow-up LL (WMD 2.51, 95% CI (1.19, 3.84), P = 0.0002), great change in LL (WMD - 2.72, 95% CI (- 4.69, - 0.76), P = 0.006), larger postoperative PJA (WMD 4.94, 95% CI (3.62, 6.26), P < 0.00001), larger follow-up PJA (WMD 13.39, 95% CI (11.09, 15.69), P < 0.00001), larger postoperative PI-LL (WMD - 9.57, 95% CI (- 17.42, - 1.71), P = 0.02), larger follow-up PI-LL (WMD - 12.62, 95% CI (- 17.62, - 7.62), P < 0.00001), larger preoperative SVA (WMD 0.73, 95% CI (0.26, 1.19), P = 0.002), larger preoperative SS (WMD - 3.43, 95% CI (- 4.71, - 2.14), P < 0.00001), RCA (WMD 1.66, 95% CI (0.48, 2.84), P = 0.006) were identified as risk factors for PJK in patients with AIS. For patients with Lenke 5 AIS, larger preoperative TK (WMD 7.85, 95% CI (5.69, 10.00), P < 0.00001), larger postoperative TK (WMD 9.66, 95% CI (1.06, 18.26), P = 0.03, larger follow-up TK (WMD 11.92, 95% CI (6.99, 16.86), P < 0.00001, larger preoperative PJA (WMD 0.72, 95% CI (0.03, 1.41), P = 0.04, larger postoperative PJA (WMD 5.54, 95% CI (3.57, 7.52), P < 0.00001), larger follow-up PJA (WMD 12.42, 95% CI 9.24, 15.60), P < 0.00001, larger follow-up SVA (WMD 0.07, 95% CI (- 0.46, 0.60), P = 0.04), larger preoperative PT (WMD - 3.04, 95% CI (- 5.27, - 0.81), P = 0.008, larger follow-up PT (WMD - 3.69, 95% CI (- 6.66, - 0.72), P = 0.02) were identified as risk factors for PJK. CONCLUSION: Following corrective surgery, 19% of AIS patients experienced PJK, with Lenke 5 contributing to 25%. Prior and post-op measurements play significant roles in predicting PJK occurrence; thus, meticulous, personalized preoperative planning is crucial. This includes considering individualized treatments based on the Lenke classification as our future evaluation standard.

Clinical efficacy and imaging analysis of oblique lateral lumbar interbody fusion in the treatment of different types of lumbar intervertebral foramen stenosis.

PURPOSE: To analyze and study the clinical efficacy and imaging indexes of oblique lateral lumbar interbody fusion (OLIF) in the treatment of lumbar intervertebral foramen stenosis(LFS) caused by different causes. METHOD: 33 patients with LFS treated with OLIF from January 2018 to May 2022 were reviewed. Oswestry Dysfunction Index (ODI) and visual analogue scale (VAS) were calculated before and after operation. Segmental lordotic angle (SLA), lumbar lordotic angle (LLA) and segmental scoliosis angle (SSA), disc height (DH), posterior disc height (PDH), lateral disc height (LDH), foraminal height (FH), foramen width (FW) and foraminal cross-sectional area (FSCA) were measured before and after operation. RESULT: The VAS and ODI after operation were significantly improved as compared with those before operation. Compared with pre-operation, the DH, PHD increased by 67.6%, 94.6%, LDH increased by 107.4% (left), 101.7% (right), and FH increased by 30.2% (left), 34.5% (right). The FSCA increased by 93.1% (left), 89.0% (right), and the FW increased by 137.0% (left), 149.6% (right). The postoperative SSA was corrected by 74.5%, the postoperative SLA, LLA were corrected by 70.2%, 38.1%, respectively. All the imaging indexes were significantly improved (p < 0.01). CONCLUSION: The clinical efficacy and imaging data of OLIF in the treatment of LFS caused by low and moderate lumbar spondylolisthesis, intervertebral disc bulge and reduced intervertebral space height, degenerative lumbar scoliosis, articular process hyperplasia or dislocation have been well improved. OLIF may be one of the better surgical treatments for LFS caused by the above conditions.

[The influencing factors on the spinal sagittal alignment and global balance status of degenerative thoracolumbar kyphosis].

Objective: To explore the effect of degenerative thoracolumbar kyphosis (DTLK) on the sagittal alignment of the spine, as well as the impact on spinal parameters and imbalance secondary to thoracolumbar kyphosis. Methods: A case-control study. A total of 128 DTLK patients who aged over 50 years [thoracolumbar kyphosis (TLK)>15°] treated in Peking University People's Hospital from January 2018 to December 2021 (DTLK group) were retrospectively included in this study. Other 73 contemporaneous patients with lumbar spinal stenosis or disc herniation without thoracolumbar kyphosis (TLK=0°±15°) were enrolled into the control group. The following parameters were obtained on spine X-ray: TLK, thoracic kyphosis (TK), lumbar lordosis (LL) and sagittal vertical axis (SVA). In addition, the osteoporosis (OP) was evaluated by dual-emission X-ray absorptiometry (DXA), and the L5/S1 disc signal grading (Pfirrmann grading) was evaluated on MRI. Based on the age, the Lafage formula SVA=2× (age-55)+25 was used to distinguish balance/imbalance, and the DTLK patients were divided into balanced and an imbalanced group, the characteristics and influencing factors of the loss of sagittal balance in this population were clarified, and the interaction among various parts of the spine under a state of balance was analyzed too. Results: The TK (30.0°±13.5° vs 24.2°±7.4°) and TLK (26.6°±9.7° vs 6.0°±6.6°) in the DTLK group were both larger than those in control group while LL was smaller (34.4°±17.7° vs 44.2°±10.3°) (all P<0.001). TK was correlated to TLK (r=0.234, P=0.008) and LL (r=0.539, P<0.001) in DTLK group. LL loss was positively correlated to L5/S1 disc signal reduction (r=0.253, P=0.044). LL loss [RR=1.04(1.01-1.08)] and OP [RR=3.97(1.09, 14.50)] were influencing factors for the occurrence of imbalance in DTLK patients. The influencing factors for TK in DTLK balance group were LL (ß=0.572, P<0.001) and age (ß=0.351, P=0.045). The positive influencing factor for TK in imbalanced group is LL (ß=0.209, P=0.015), and the impact is weaker than balanced group. Conclusions: Loss of LL and osteoporosis are more likely to cause imbalance and kyphosis in DTLK patients. In DTLK balance group, the proximal spine is regulated by lumbar spine, and the synergistic effect between the two parts maintains balance.

Lumbar lordosis and sacral slope do not differ in two types of postoperative lumbar disc re-herniation: a cross-sectional observational study.

BACKGROUND: To identify the differences of lumbar lordosis (LL) and sacral slope (SS) angles between two types of postoperative lumbar disc re-herniation, including the recurrence of same level and adjacent segment herniation (ASH). METHODS: We searched the medical records of lumbar disc herniation (LDH) patients with re-herniation with complete imaging data (n = 58) from January 1, 2013 to December 30, 2020 in our hospital. After matching for age and sex, 58 patients with LDH without re-herniation from the same period operated by the same treatment group in our hospital were served as a control group. Re-herniation patients were divided into two groups, same-level recurrent lumbar disc herniation group (rLDHG) and adjacent segment herniation group with or without recurrence (ASHG). The preoperative, postoperative and one month after operation LL and SS were measured on standing radiographs and compared with the control group by using t-test, ANOVA, and rank-sum test. Next, we calculated the odds ratios (ORs) by unconditional logistic regression, progressively adjusted for other confounding factors. RESULTS: Compared with the control group, the postoperative LL and SS were significantly lower in LDH patients with re-herniation. However, there were no differences in LL and SS between ASHG and rLDHG at any stage. After progressive adjustment for confounding factors, no matter what stage is, LL and SS remained unassociated with the two types of re-herniation. CONCLUSIONS: Low postoperative LL and SS angles are associated with degeneration of the remaining disc. Low LL and SS may be independent risk factors for re-herniation but cannot determine type of recurrence (same or adjacent disc level).

Analyzing lumbar vertebral shape and alignment in female patients with degenerative spondylolisthesis: Comparisons with spinal stenosis and risk factor exploration.

PURPOSE: This study aimed to examine the vertebral body shape characteristics and spondylopelvic alignment in L4 degenerative spondylolisthesis (DS) as well as the risk factors for the development of DS. METHODS: This cross-sectional study compared vertebral morphology and sagittal spinopelvic alignment in female patients with lumbar DS and lumbar spinal stenosis (LSS). The degree of lumbar lordosis (LL), pelvic incidence (PI), cross-sectional area (CSA), and vertebral body height ratio (ha/hp) of the lumbar spine were compared using full-length spine radiographs and computed tomography in 60 females with DS and in 60 women with LSS. RESULTS: No significant differences in age or body mass index were observed between the two groups; however, the DS and LSS groups significantly differed in PI (mean, 58.9±10.8 vs. 47.2±11.6, P < 0.001), L4 CSA (mean, 1,166.2 m2 vs. 1,242.0 m2, P = 0.002) and ha/hp (mean, 1.134 vs. 1.007, P < 0.001). The L4 ha/hp was significantly higher in the DS group than in the LSS group. Additionally, LL values were negatively correlated with vertebral L5 CSA in the DS group (r = -0.28, P < 0.05). The LSS and DS groups demonstrated positive correlations between LL and L2, L3, and L4 ha/hp (r = 0.331, 0.267, and 0.317; P < 0.01, < 0.05, and < 0.05, respectively) and between LL and L4 and L5 ha/hp (r = 0.333, 0.331; P < 0.01, respectively). Multivariate regression analyses revealed that PI and ha/hp ratio may be independent predictors of DS development. CONCLUSION: The DS group had significantly larger LL, PI, and L4 ha/hp and smaller L4 CSA than the LSS group. The lumbar vertebral body shape and sagittal spinopelvic alignment in females might be independent predictors of DS development.

Gender differences in spinal mobility during postural changes: a detailed analysis using upright CT.

Lumbar spinal alignment is crucial for spine biomechanics and is linked to various spinal pathologies. However, limited research has explored gender-specific differences using CT scans. The objective was to evaluate and compare lumbar spinal alignment between standing and sitting CT in healthy individuals, focusing on gender differences. 24 young and 25 elderly males (M) and females (F) underwent standing and sitting CT scans to assess lumbar spinal alignment. Parameters measured and compared between genders included lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), lordotic angle (LA), foraminal height (FH), and bony boundary area (BBA). Females showed significantly larger changes in SS and PT when transitioning from standing to sitting (p = .044, p = .038). A notable gender difference was also observed in the L4-S LA among the elderly, with females showing a significantly larger decrease in lordotic angle compared to males (- 14.1° vs. - 9.2°, p = .039*). Females consistently exhibited larger FH and BBA values, particularly in lower lumbar segments, which was more prominent in the elderly group (M vs. F: L4/5 BBA 80.1 mm2 [46.3, 97.8] vs. 109.7 mm2 [74.4, 121.3], p = .019 in sitting). These findings underline distinct gender-related variations in lumbar alignment and flexibility, with a focus on noteworthy changes in BBA and FH in females. Gender differences in lumbar spinal alignment were evident, with females displaying greater pelvic and sacral mobility. Considering gender-specific characteristics is crucial for assessing spinal alignment and understanding spinal pathologies. These findings contribute to our understanding of lumbar spinal alignment and have implications for gender-specific spinal conditions and treatments.

L1 slope: an overlooked spinal parameter.

OBJECTIVE: Lumbar lordosis can be divided into two parts by a horizontal line, creating the L1 slope and the sacral slope. Despite being a major spinopelvic parameter, the L1slope (L1S) is rarely reported. However, there is some evidence that L1S is a relatively constant parameter. This study aimed to analyze the L1 slope and its relationships with other spinopelvic parameters. METHODS: Standing lateral lumbosacral x-ray radiographies of 76 patients with low back pain and CT scans of 116 asymptomatic subjects were evaluated for spinal and spinopelvic parameters including L1 slope (L1S). The x-ray and CT groups were divided into subgroups according to mean sacral slope (SS) or pelvic incidence (PI) values. The mean values of the spinopelvic parameters and the correlations between them were investigated and compared. RESULTS: L1S was 19.70 and 18.15 in low SS and high SS subgroups of x-ray respectively. L1S was 7.95 and 9.36 in low and high PI subgroups of CT, respectively, and the differences were insignificant statistically. L1S was the only spinal parameter that did not change as SS or PI increased in standing and supine positions. L1S was correlated with lumbar lordosis (LL) proximal lumbar lordosis (PLL) and distal lumbar lordosis (DLL) in both x-ray and CT groups. L1S was also the strongest correlated parameter with pelvic incidence lumbar lordosis mismatch (PI-LL) mismatch in supine position. CONCLUSIONS: L1S is a relatively constant parameter and is around 16°-18° and 8°-9° in the standing and supine positions, respectively. It was significantly correlated with LL, PLL, DLL, and PI-LL. In the standing position it was nearly equal to PLL while this equality was present in low PI subgroups of CT. There is strong evidence that L1S is significantly correlated with health-related quality of life scores.

Meta-analysis of the efficacy and safety of OLIF and TLIF in the treatment of degenerative lumbar spondylolisthesis.

OBJECTIVE: To systematically evaluate the difference in clinical efficacy between two surgical approaches, oblique lateral approach and intervertebral foraminal approach, in the treatment of degenerative lumbar spondylolisthesis. METHODS: English databases, including PubMed, Cochrane, Embase, and Web of Science, were systematically searched using keywords such as "oblique lumbar interbody fusion" and "transforaminal lumbar interbody fusion." Concurrently, Chinese databases, including CNKI, WanFang data, VIP, and CBM, were also queried using corresponding Chinese terms. The search spanned from January 2014 to February 2024, focusing on published studies in both Chinese and English that compared the clinical efficacy of OLIF and TLIF. The literature screening was conducted by reviewing titles, abstracts, and full texts. Literature meeting the inclusion criteria underwent quality assessment, and relevant data were extracted. Statistical analysis and a meta-analysis of the observational data for both surgical groups were performed using Excel and RevMan 5.4 software. Findings revealed a total of 14 studies meeting the inclusion criteria, encompassing 877 patients. Of these, 414 patients were in the OLIF group, while 463 were in the TLIF group. Meta-analysis of the statistical data revealed that compared to TLIF, OLIF had a shorter average surgical duration (P < 0.05), reduced intraoperative bleeding (P < 0.05), shorter average hospital stay (P < 0.05), better improvement in postoperative VAS scores (P < 0.05), superior enhancement in postoperative ODI scores (P < 0.05), more effective restoration of disc height (P < 0.05), and better correction of lumbar lordosis (P < 0.05). However, there were no significant differences between OLIF and TLIF in terms of the incidence of surgical complications (P > 0.05) and fusion rates (P > 0.05). CONCLUSION: When treating degenerative lumbar spondylolisthesis, OLIF demonstrates significant advantages over TLIF in terms of shorter surgical duration, reduced intraoperative bleeding, shorter hospital stay, superior improvement in postoperative VAS and ODI scores, better restoration of disc height, and more effective correction of lumbar lordosis.

[Comparative study of percutaneous transfacet screw and pedicle screw in oblique lumbar interbody fusion for the treatment of single-level lumbar spinal stenosis].

Objective: To conduct a comparative study of radiological and clinical outcomes between percutaneous transfacet screw (TFS) and pedicle screw (BPS) in oblique lateral lumbar interbody fusion (OLIF) for single-level lumbar spinal stenosis. Methods: A retrospective cohort study. Patients who underwent OLIF with TFS or BPS for the treatment of single-level lumbar spinal stenosis at Beijing Jishuitan Hospital from January 2019 to June 2022 were retrospectively analyzed. Radiological parameters and clinical indicators were compared between the two groups. Radiological parameters included preoperative, immediate postoperative (within 5 days), and 1-year postoperative measurements of disc height and segmental lordosis angle, as well as interbody fusion status at 1 year postoperatively. Clinical indicators included operative time, blood loss, length of hospital stay, complications, and Oswestry Disability Index (ODI), visual analogue scale (VAS) scores for back pain, and leg pain before and 1 year after surgery. Results: Four male and 10 female patients with an average age of (61.0±11.2) years underwent OLIF with TFS, while 9 male and 12 female patients underwent OLIF with BPS, with a mean age of (60.9±6.7) years. There was no statistically significant difference in preoperative disc height between the TFS and BPS groups (P>0.05). The immediate postoperative disc height was (12.9±2.1) mm and it was (10.4±1.7) mm at 1-year follow-up in the TFS group; in the BPS group, it was (12.9±2.1) mm immediately postoperatively and (11.9±2.1) mm at 1-year follow-up; there was statistically significant difference between the two groups at 1-year follow-up (P=0.037). The segmental lordosis angle showed no significant differences within each group or between the two groups at preoperative, immediate postoperative, or 1-year postoperative follow-up (all P>0.05). At 1-year postoperative follow-up, the fusion rates was 92.9%(13/14) in the TFS group and 95.2%(20/21) in the BPS group, with no statistically significant difference between the two groups (P>0.05). The TFS group had a significantly shorter operative time and less blood loss compared to the BPS group [(164.3±33.9) minutes vs (191.7±31.8) minutes and (74.3±46.9) ml vs (124.8±54.0) ml, respectively] (both P<0.05). Both groups showed significant improvement in ODI and VAS scores at 1 year postoperatively compared to those preoperatively, but with no statistically significant difference was found between the groups (both P>0.05). Conclusions: OLIF with TFS fixation can effectively restore disc height and alleviate back and leg pain in patients with single-level lumbar spinal stenosis. Compared to the OLIF with BPS procedure, OLIF with TFS has shorter operative time and less blood loss.

[Effect of Kümmell's disease with kyphosis on spinal-pelvic sagittal parameters].

OBJECTIVE: To explore the effect of Kümmell's disease with kyphosis on the sagittal morphology of the spine-pelvis. METHODS: A retrospective analysis of 34 patients of Kümmell's disease with kyphosis （Kümmell group） admitted from August 2015 to September 2022, including 10 males and 24 females with an average age of （71.1±8.5） years old. A control group of 37 asymptomatic population aged （69.3±6.7） years old was matched. Spinal-pelvic sagittal parameters were measured on the anterior-posterior and lateral X-rays of the whole spine in the standing position, including segmental kyphosis（SK） or thoracolumbar kyphosis（TLK）, thoracic kyphosis（TK）, lumbar lordosis（LL）, pelvic incidence（PI）, pelvic tilt（PT）, sacral slope（SS）, sagittal vertical axis（SVA）, T1 pelvic angle（TPA） and PI-LL. Vertebral wedge angle（WA） in Kümmell was measured and differences in parameters among groups were analyzed and the relationship between spino-pelvic parameters and WA, SK were also investigated. RESULTS: TK, SK, PT, SVA, TPA and PI-LL in Kümmell group were significantly larger than those in control group （P<0.05）, LL and SS in Kümmell group were significantly decreased than those in control group （P<0.05）, and there was no significant difference in PI between two groups （P>0.05）. In Kümmell group, WA（30.8±5.9）° showed a positive correlation with SK and TK（r=0.366, 0.597, P<0.05）, and SK was significantly correlated with LL and SS（r=0.539, -0.591, P<0.05）. Strong positive correlation between LL and PI, SS, SVA, TPA, PI-LL were also confirmed in patients with Kümmell with kyphosis（r=0.559, 0.741, -0.273, -0.356, -0.882, P<0.05）. CONCLUSION: Patients with Kümmell with kyphosis not only have segmental kyphosis, but also changes the overall spinal-pelvic sagittal parameters, including loss of lumbar lordosis, pelvic retrorotation, trunk forward tilt. The surgical treatment of Kümmell disease should not only pay attention to the recovery of the height of the collapsed vertebra, but also focus on the overall balance of the spine-pelvic sagittal plane for patients with kyphosis.

[Clinical study on the treatment of postoperative recurrence of lumbar disc herniation with intervertebral fusion].

OBJECTIVE: To explore clinical effect of different intervertebral fusion devices (cage) in treating postoperative recurrent lumbar disc herniation (LDH). METHODS: One hundred and forty-two LDH patients with recurrence after simple intervertebral disc nucleus pulpoideectomy from January 2019 to January 2021 were retrospectively analyzed. All patients were treated with combined underchannel fixation and interbody fusion and divided into a single anatomical group,two-anatomical group and a single banana group according to types and numbers of implanted cage. There were 51 patients in a single anatomical group,included 29 males and 22 females,aged from 39 to 65 years old with an average of (53.74±5.68) years old;body mass index (BMI) ranged from 18.62 to 28.13 kg·m-2 with an average of (22.08±2.15) kg·m-2;the interval between operation and recurrence ranged from 0.5 to 4.0 years with an average of (2.7±0.8) years;5 patients with L3,4,35 patients with L4,5 and 11 patients with L5S1;a single anatomical cage was implanted. There were 46 patients in two-anatomical group,included 25 males and 21 females,aged from 37 to 66 years old with an average of (54.52±6.02) years old;BMI ranged from 18.25 to 28.44 kg·m-2 with an average of (21.74±1.83) kg·m-2;the interval between operation and recurrence ranged from 0.5 to 5.0 years with an average of (2.7±0.9) years;4 patients with L3,4,32 patients with L4,5 and 10 patients with L5S1;two-anatomical cages were implanted. There were 45 patients in a single banana group,included 22 males and 23 females,aged from 38 to 65 years old with an average of (54.49±6.45) years old;BMI ranged from 18.85 to 28.20 kg·m-2 with an average of (21.63±1.59) kg·m-2;the interval between operation and recurrence ranged from 0.5 to 5.0 years with an average of (2.6±1.0) years;3 patients with L3,4,36 patients with L4,5 and 16 patients with L5S1;a single banana cage was implanted. Operation time,intraoperative blood loss,incision length,postoperative incision drainage volume,hospital stay and complications among 3 groups were observed and compared. The height of intervertebral space before and after operation,curvature of lordosis and the postoperative intervertebral fusion were compared. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to evaluate degree of lumbar pain and lumbar function before operation,1 and 6 months after operation,respectively. RESULTS: All patients among 3 groups were followed up at least 6 months,and no cases were fell out. There were no significant difference in operation time,intraoperative blood loss,incision length,postoperative incision drainage volume and hospital stay among 3 groups (P>0.05). At 6 months after operation,the height of intervertebral space in two-anatomical group and a single group were [(11.08±1.78) mm,(10.95±1.62) mm],curvature of lordosis were [(12.05±1.86) °,(11.63±1.57) °],which were higher than those in a single dissection group (10.14±1.54) mm,(10.92±1.45) °,and the difference were statistically significant (P<0.05). The interbody fusion rate between two-anatomical and a banana group (95.65%,95.56%) were higher than that in a single anatomical group (78.43%) at 6 months after operation (P<0.05). VAS and ODI of lumbar among 3 groups were decreased at 1 and 6 months after operation (P<0.05). There was no significant difference in complications among 3 groups (P>0.05). CONCLUSION: The three fusion devices could achieve significant results in treating postoperative recurrence of LDH,but the implantation of two-anatomical cage and a single banana cage are more helpful to maintain the height of intervertebral space and lordosis curvature of patients with postoperative recurrence of LDH,and obtain good intervertebral fusion results.

Is the anterior approach still superior to posterior correction in AIS regarding correction, fusion levels and kyphosis when modern posterior systems are used?

PURPOSE: The aim of our study is to compare anterior and posterior corrections of thoracic (Lenke I) and lumbar (Lenke V) curves when modern posterior pedicle screw systems with vertebral derotation techniques are used. Curves that could not be corrected with both systems were excluded. METHODS: A thoracic group (N = 56) of Lenke I AIS patients (18 anterior and 38 posterior) and a lumbar group (N = 42) of Lenke V patients (14 anterior and 28 posterior) with similar curves < 65° were identified. RESULTS: Thoracic group The mean postoperative correction (POC) was 68 ± 13.4% in the anterior and 72 ± 10.5% in the posterior group. The postoperative change in thoracic kyphosis was +4° and +5° respectively. The median length of fusion was eight segments in the posterior and seven segments in the anterior groups. In 89% the LIV was EV or shorter in the anterior, and in 71% of the posterior corrections. Lumbar group The mean POC was 75 ± 18.3% (anterior) and 72 ± 8.5% (posterior). The postoperative gain in lumbar lordosis was 0.8° (anterior) and 4° (posterior). The median length of fusion was five segments in both groups and there was no difference in relation of the LIV to the EV. CONCLUSION: With modern implants and derotation techniques, the posterior approach can achieve similar coronal correction, apical derotation and thoracic kyphosis with similar length of fusion and better lumbar lordosis restoration.

Landet: an efficient physics-informed deep learning approach for automatic detection of anatomical landmarks and measurement of spinopelvic alignment.

PURPOSE: An efficient physics-informed deep learning approach for extracting spinopelvic measures from X-ray images is introduced and its performance is evaluated against manual annotations. METHODS: Two datasets, comprising a total of 1470 images, were collected to evaluate the model's performance. We propose a novel method of detecting landmarks as objects, incorporating their relationships as constraints (LanDet). Using this approach, we trained our deep learning model to extract five spine and pelvis measures: Sacrum Slope (SS), Pelvic Tilt (PT), Pelvic Incidence (PI), Lumbar Lordosis (LL), and Sagittal Vertical Axis (SVA). The results were compared to manually labelled test dataset (GT) as well as measures annotated separately by three surgeons. RESULTS: The LanDet model was evaluated on the two datasets separately and on an extended dataset combining both. The final accuracy for each measure is reported in terms of Mean Absolute Error (MAE), Standard Deviation (SD), and R Pearson correlation coefficient as follows: [ S S ∘ : 3.7 ( 2.7 ) , R = 0.89 ] , [ P T ∘ : 1.3 ( 1.1 ) , R = 0.98 ] , [ P I ∘ : 4.2 ( 3.1 ) , R = 0.93 ] , [ L L ∘ : 5.1 ( 6.4 ) , R = 0.83 ] , [ S V A ( m m ) : 2.1 ( 1.9 ) , R = 0.96 ] . To assess model reliability and compare it against surgeons, the intraclass correlation coefficient (ICC) metric is used. The model demonstrated better consistency with surgeons with all values over 0.88 compared to what was previously reported in the literature. CONCLUSION: The LanDet model exhibits competitive performance compared to existing literature. The effectiveness of the physics-informed constraint method, utilized in our landmark detection as object algorithm, is highlighted. Furthermore, we addressed the limitations of heatmap-based methods for anatomical landmark detection and tackled issues related to mis-identifying of similar or adjacent landmarks instead of intended landmark using this novel approach.

Rod fracture after multiple-rod technique for adult spinal deformity: a case report.

Here we report the case of a 71-year-old woman who complained of lower back and left leg pain due to rod fracture following instrumented fusion using the lateral lumbar interbody fusion and multi-rod technique to treat adult spinal deformity. Radiographic images revealed bilateral rod fractures at L4-5 and pseudoarthrosis at L2-5; lower lumbar lordosis was minimal, but upper lumbar hyperlordosis was noted. The patient underwent revision surgery, which included posterior spinal instrument replacement, L3-4 and L4-5 lateral lumbar interbody fusion cage removal, and L4 vertebral body replacement via the anterior approach. This is a rare case of reoperation with the multi-rod technique. Revision surgery should be performed in consideration of the proportion of lumbar lordosis and anterior bony fusion as the posterior component is resected and bony fusion can only be achieved anteriorly.

Novel Risk Factors for Cervical Facet Joint Degeneration in the Subaxial Cervical Spine: Correlation with Cervical Sagittal Alignment and Bone Mineral Density.

OBJECTIVE: The impact of cervical sagittal alignment on cervical facet joint degeneration (CFD) and the risk factors for CFD in patients with degenerative cervical myelopathy (DCM) were investigated in the current study. METHODS: A total of 250 surgical patients with DCM were recruited. The clinical data and radiographical characteristics, including CFD, cervical sagittal balance parameters, Hounsfield unit (HU) values, disc degeneration (DD), and modic change, were collected. The detailed correlation between these characteristics and CFD was analyzed. Characteristics, including CFD, were compared among the various cervical alignment types and different CFD groups. Finally, the risk factors for CFD were revealed via logistic regression. RESULTS: CFD was prevalent in DCM patients. Age, cervical sagittal vertical axis (cSVA), range of motion, T1 slope, thoracic inlet angle, DD, HU value, and modic change correlated with CFD segmentally and globally (P < 0.05). The lordosis and sigmoid types had a significantly higher CFD prevalence (P < 0.05). Furthermore, the average CFD threshold for the severe CFD group was 1.625 (area under the curve, 0.958). Additionally, 167 patients with average CFD <1.625 and 83 patients with CFD of ≥1.625 were classified into the mild CFD group and severe CFD group, respectively. Finally, multivariate analysis was performed, and age, cSVA, HU value, modic change, and DD were determined to be independent risk factors for CFD. CONCLUSIONS: The load distribution tends to shift to a more shear-like pattern in the sigmoid and kyphosis types and in those with a higher cSVA, thereby promoting CFD. Aging, cervical malalignment, low bone mineral density, DD, and modic change were revealed to result in high risks of CFD.

Association patterns between lumbar paraspinal muscles and sagittal malalignment in preoperative patients undergoing lumbar three-column osteotomy.

PURPOSE: We aim to investigate the associations between lumbar paraspinal muscles and sagittal malalignment in patients undergoing lumbar three-column osteotomy. METHODS: Patients undergoing three-column osteotomy between 2016 and 2021 with preoperative lumbar magnetic resonance imaging (MRI) and whole spine radiographs in the standing position were included. Muscle measurements were obtained using a validated custom software for segmentation and muscle evaluation to calculate the functional cross-sectional area (fCSA) and percent fat infiltration (FI) of the m. psoas major (PM) as well as the m. erector spinae (ES) and m. multifidus (MM). Spinopelvic measurements included pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), L1-S1 lordosis (LL), T4-12 thoracic kyphosis (TK), spino-sacral angle (SSA), C7-S1 sagittal vertical axis (SVA), T1 pelvic angle (TPA) and PI-LL mismatch (PI - LL). Statistics were performed using multivariable linear regressions adjusted for age, sex, and body mass index (BMI). RESULTS: A total of 77 patients (n = 40 female, median age 64 years, median BMI 27.9 kg/m2) were analyzed. After adjusting for age, sex and BMI, regression analyses demonstrated that a greater fCSA of the ES was significantly associated with greater SS and SSA. Moreover, our results showed a significant correlation between a greater FI of the ES and a greater kyphosis of TK. CONCLUSION: This study included a large patient cohort with sagittal alignment undergoing three-column osteotomy and is the first to demonstrate significant associations between the lumbar paraspinal muscle parameters and global sagittal alignment. Our findings emphasize the importance of the lumbar paraspinal muscles in sagittal malalignment.

[Sagittal Profi le of the Spine in Patients after Lumbar Stabilisation Surgeries]. / Sagitální profi l pátere u pacientu po stabilizacních operacích bederní pátere.

PURPOSE OF THE STUDY: Spine stabilization surgery is nowadays one of the most common spinal surgical procedures. Spinopelvic alignment is considered to be an important factor impacting the patients' preoperative diffi culties as well as the outcome of surgery. In our study, the outcomes of stabilization surgeries in patients with lumbar spine disorders were evaluated - especially in those with stenosis and spondylolisthesis, in whom the importance of sagittal parameters were assessed with respect to the patients' clinical outcomes and diffi culties. MATERIAL AND METHODS: The study included 50 patients with lumbar spine disorders who had undergone a spine stabilization surgery for a degenerative disease - lumbar spinal stenosis, spondylolisthesis between 2015 and 2017. Spino-pelvic radiological parameters and clinical parameters were evaluated using the nonparametric Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests. RESULTS: In 38 of 50 patients, who at the end of the follow-up period did not have the PI-LL (pelvic incidence-lumbar lordosis) mismatch, i.e. PI-LL was ≤10°, a statistically signifi cant difference in pelvic tilt (p=0.049) and sagittal vertical axis (p<0.001) was reported, which was not the case in the remaining patients of the study population. Claudication and OSWESTRY (ODI) showed no statistically signifi cant difference. We have also compared the differences in the number of fused vertebrae and type of stabilization. A signifi cant change was seen in the claudication parameter at 12 and 24 months after surgery (p=0.007, p=0.005), with better outcomes achieved by 360° lumbar fusion compared to posterior lumbar fusion. The improvement of VAS and ODI scores in both the groups over time (from 6.1 to 3.6 or from 6.3 to 3.5 in VAS and from 62 to 32, or from 62 to 30 in ODI) was also statistically signifi cant (p<0.001 in both groups), while when comparing the groups against each other it was statistically insignifi cant. DISCUSSION: The authors confi rmed signifi cant improvement in the studied clinical parameters in all groups of patients (VAS, ODI, claudication), which is consistent with the results of recently published papers. The authors also established the correlation between different radiological parameters in the studied groups. The results do not confi rm the importance of the length or type of instrumentation for the clinical outcomes. This is consistent with the fi ndings of other published manuscripts. The authors failed to confi rm a signifi cant change in clinical parameters in dependence on the matching relationship between the pelvic incidence and lumbar lordosis. CONCLUSIONS: Proper spinopelvic balance in patients after spinal surgery is a very important indicator of postoperative development and condition, but our cohort showed no statistically signifi cant difference in the clinical outcomes of patients whose postoperative sagittal parameters were unsatisfactory. KEY WORDS: sagittal profi le, spine stabilization, pelvic tilt, pelvic incidence, sagittal vertical axis, SVA.