A Novel Radiological Scoring System for Anterior Longitudinal Ligament Injuries.

Background and Aim: Cervical hyperextension injury is very frequent with anterior longitudinal ligament (ALL) injury, and the ligament damage has a remarkable effect on whether and what type of operation should be performed. This study aims to establish a new scoring system for the accurate diagnosis of ALL damage. Methods: The imaging data of the consecutive patients was measured and scored by four radiologists. Intraoperative exploration was performed by three surgeons. The crude and adjusted odds ratios (cOR and aOR) and receiver operating characteristic curve (ROC) were constructed to assess the diagnostic accuracy of the scoring system. Results: A total of 255 patients with cervical spine trauma were included in this study. There was no statistical difference in the relationship between demographics and ALL injuries (P > 0.05). Thickness of prevertebral soft tissue (aOR = 11.922, P = 0.004), intervertebral disk angle (aOR = 13.21, P = 0.002), avulsion fracture of the anterior edge of the vertebral body (aOR = 13.844, P = 0.029), ALL disrupted in T1-weighted sequence (aOR = 18.349, P < 0.001), and high signal area in T2-weighted sequence (aOR = 20.898, P = 0.002) had significantly higher diagnostic accuracy. The scoring system's sensitivity and specificity were 94.0% and 88.1%, respectively, and the accuracy was 90.8%. Conclusion: The study established a new scoring system for ALL injuries based on the analysis of a series of clinical data and statistics. A total of five scoring items, a total score of 7 points, and an ALL injury may be diagnosed when the score is not less than 3 points. This scoring system enables an efficient and accurate diagnosis of all injuries.

Pelvic Incidence as a Predictor of Proximal Junctional Failure in Patients Undergoing Anterior Column Realignment with Anterior Longitudinal Ligament Release to Restore Lordosis in Adult Spinal Deformity: A Retrospective Cohort Study.

OBJECTIVE: To identify variables that may contribute to the development of proximal junctional failure (PJF) in patients with long lumbo-sacral and thoraco-lumbo-pelvic constructs undergoing anterior column realignment (ACR) with anterior longitudinal ligament release (ALLR). METHODS: Data of patients with adult spinal deformity who underwent ACR with ALLR at L3-4 were collected retrospectively from medical records and a prospectively maintained spine research database between 2016 and 2022. RESULTS: Eleven (41%) developed PJF at a mean of 24 ± 21 months from the index surgery. The cohort was then divided into 2 groups for analysis, 13 subjects in the high pelvic incidence (PI) group (defined as PI ≥ 55°) and 14 subjects in the low PI group (defined as PI < 55°). Visual Analog Scale for back pain and Oswestry Disability Index decreased from 9.5 to 2.1 and 61 to 10 in the high PI group, and from 8.9 to 2.4 and 60.9 to 10.3 in the low PI group, respectively. PI (P = 0.004), sacral slope (P = 0.005), and postoperative PI-lumbar lordosis mismatch (P = 0.02) were found to be significant predictors of PJF. The receiver operator curve revealed a cutoff PI value ≤ 53° (95% confidence interval: 52°-64°), below which the risk of PJF becomes significantly higher in patients undergoing ACR with ALLR at L3-4. CONCLUSIONS: PI may be a predictor of PJF and highly correlates with ACR-ALLR levels. In patients undergoing L3-4 ACR-ALLR, a PI value of ≤53° is associated with a significantly elevated risk of PJF. Preoperative planning of ACR-ALLR level based on normal sagittal alignment in otherwise healthy individuals may mitigate the risk of PJF development in patients with adult spinal deformity treated with ACR-ALLR.

Anterior column realignment via a minimally invasive hybrid approach in adult spinal deformity surgery: a short-term retrospective study.

BACKGROUND: Anterior column realignment (ACR) is a novel surgical method for correcting spinal sagittal balance. meanwhile, oblique lumbar interbody fusion (OLIF) and anterior lumbar interbody fusion (ALIF) are considered minimally invasive surgical methods through natural anatomical space. This study aimed to explore the corrective effects and clinical outcomes of OLIF or ALIF combined with ACR technology in patients with adult spinal deformity (ASD). METHODS: We retrospectively analyzed patients with sagittal imbalance who received OLIF and/or ALIF and ACR treatment from 2018 to 2021. Surgical time and intraoperative bleeding volume are recorded, the corrective effect is determined by the intervertebral space angle (IVA), lumbar lordosis (LL), the sagittal vertical axis (SVA), clinical outcome is evaluated by preoperative and final follow-up visual analog pain score (VAS), Japanese orthopedic association scores (JOA) and complications. RESULTS: Sixty-four patients were enrolled in the study, average age of 65.1(range, 47-82) years. All patients completed 173 fusion segments, for 150 segments of ACR surgery. The operation time of ALIF-ACR was 50.4 ± 22.1 min; The intraoperative bleeding volume was 50.2 ± 23.6 ml. The operation time and intraoperative bleeding volume of single-segment OLIF-ACR was 66.2 ± 19.4 min and 70.2 ± 31.6 ml. At the follow-up of 6 months after surgery, the intervertebral space angle correction for OLIF-ACR and ALIF-ACR is 9.2° and 12.2°, the preoperative and postoperative lumbar lordosis were 16.7° ± 6.4°and 47.1° ± 3.6° (p < 0.001), VAS and JOA scores were improved from 6.8 to 1.8 and 7.8 to 22.1 respectively, statistically significant differences were observed in these parameters. The incidence of surgical related complications is 29.69%, but without serious complications. CONCLUSION: ACR via a minimally invasive hybrid approach for ASD has significant advantages in restoring local intervertebral space angulation and correcting the overall sagittal balance. Simultaneously, it can achieve good clinical outcomes and fewer surgical complications.

The Early Effects of Longus Colli Muscle and Anterior Longitudinal Ligament Reconstructions on Swallowing Function after Anterior Cervical Surgery: A Six-Month Follow-Up Study.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) is the gold standard surgery used to treat cervical degenerative disease. Dysphagia and hoarseness are the two most common complications that occur after anterior cervical surgery (ACS). In this study, we aim to evaluate the early effects of longus colli muscle (LCM) and anterior longitudinal ligament (ALL) reconstructions on swallowing function after ACS. METHODS: We recruited 91 patients (35 males and 56 females; mean age: 49.41 ± 8.60 years [range: 26-72 years]) who have undergone either ACDF or anterior cervical corpectomy and fusion (ACCF) between August 2019 and October 2021. Patients were divided into LCM and ALL suture group (Group A), and LCM and ALL non-suture group (Group B). Assessments of the incidence of dysphagia and the swallowing quality of life (SWAL-QOL) were completed in 2 days, 1 week, 1 month, 3 months and 6 months after surgery. Average prevertebral soft tissue thickness (APSTT) were measured on lateral cervical spine radiographs taken with X-rays 2 days, 1 month, 3 months and 6 months after surgery. RESULTS: In the 2-day, 1-week and 1-month postoperative follow-up, the incidence of dysphagia in group A was significantly lower than that in group B (p < 0.05), and the SWAL-QOL scores of group A were significantly higher than those of group B (p < 0.05). In the 3-month and 6-month postoperative follow-up, no significant differences were found between groups A and B in terms of the incidence of dysphagia (p > 0.05). In the 6-month postoperative follow-up, no significant differences were found between the groups in terms of SWAL-QOL scores (p > 0.05). There were no significant differences in APSTT between groups during postoperative follow-up (p > 0.05). CONCLUSION: The reconstructions of LCM and ALL in ACS can effectively improve short-term postoperative swallowing function.

Anterior Column Realignment: Adult Sagittal Deformity Treatment Through Minimally Invasive Surgery.

This article focuses on the treatment of sagittal spinal deformity using a minimally invasive technique, anterior column realignment. Traditional methods to address sagittal spine deformity have been associated with high morbidity, long operative times, and excessive blood loss. This technique uses a minimally invasive lateral retroperitoneal approach to release the anterior longitudinal ligament and apply a hyperlordotic implant for interbody fusion to restore lumbar lordosis and sagittal alignment.

Elucidation of the Mechanism of Occasional Anterior Longitudinal Ligament Rupture with Posterior Correction Procedure for Adult Spinal Deformity Using LLIF-Finite Element Analysis of the Impact of the Lordotic Angle of Intervertebral LLIF Cage.

Background and Objectives: There are several advantages of using lateral lumbar interbody fusion (LLIF) for correction surgeries for adult spinal deformity (ASD); however, we currently have unresolved new issues, including occasional anterior longitudinal ligament (ALL) rupture during the posterior correction procedure. When LLIF was initially introduced, only less lordotic cages were available and ALL rupture was more frequently experienced compared with later periods when more lordotic cages were available. We performed finite element analysis (FEA) regarding the mechanism of ALL rupture during a posterior correction procedure. Methods: A spring (which mimics ALL) was introduced at the location of ALL in the FEA and an LLIF cage with two different lordotic angles, 6 and 12 degrees (6DC/12DC), was employed. To assess the extent of burden on the ALL, the extension length of the spring during the correction procedure was measured and the location of the rotation center was examined. Results: We observed a significantly higher degree of length extension of the spring during the correction procedure in the FEA model with 6DC compared with that of 12DC. We also observed that the location of the rotation center was shifted posteriorly in the FEA model with 6DC compared with that of 12DC. Conclusions: It is considered that the posterior and rostral edge of the less lordotic angle cage became a hinge, and the longer lever arm increased the burden on ALL as the principle of leverage. It is important to use an LLIF cage with a sufficient lordotic angle, that is compatible with the degree of posterior osteotomy in ASD correction.

Indirect Decompression of Osteoporotic Vertebral Compression Fracture Using Intraoperative Motor Evoked Potential Monitoring-Guided Ligamentotaxis.

Osteoporotic vertebral compression fractures have become common in aging societies and can lead to a decreased quality of life with severe back pain and neurological deficits. Traditional direct decompression and stabilization surgeries can produce sufficient decompression and provide good results. However, after surgical treatment, some elderly patients with numerous chronic diseases often experience severe postoperative complications owing to the long surgery duration and massive bleeding. Therefore, to prevent perioperative morbidity, other surgical methods that simplify the surgical process and reduce the operation time are required. Herein, we describe a case of indirect decompression using ligamentotaxis and sequential anabolic agents. To examine their effectiveness during surgery, we monitored intraoperative motor-evoked potentials. The patient's neurological symptoms improved postoperatively. After the operation, the anabolic agent "romosozumab" was injected monthly to treat osteoporosis, prevent additional fractures, and accelerate posterolateral fusion. On serial follow-up, the anterior body height of the fractured vertebra improved significantly, demonstrating the importance of osteoporosis treatment using anabolic agents. Indirect decompression surgery may have early effects, whereas sequential anabolic agent use may consolidate the long-term effects of surgical treatment.

Ossification of the anterior longitudinal ligament affects the severity and distribution of neurological deficits following spinal cord injury without radiological abnormality.

BACKGROUND: The incidence of spinal cord injury without radiological abnormality (SCIWORA) is increasing among older adults in developed countries. SCIWORA is commonly associated with ossification of the spinal ligament, specifically the ossification of the posterior longitudinal ligament (OPLL) and ossification of the anterior longitudinal ligament (OALL). OALL induces segmental spinal fusion and alters the biomechanical properties of the cervical spine; however, whether OALL modulates the severity of SCIWORA remains unknown. This study aimed to investigate the influence of OALL on the severity and distribution of neurological deficits following SCIWORA. METHODS: This retrospective study included 122 patients with SCIWORA who were admitted to our hospital from April 2008 to March 2022. The neurological function of all the included patients was assessed via the American Spinal Injury Association (ASIA) Impairment Scale (AIS) at admission. Magnetic resonance imaging (MRI) and computed tomography were performed within 48 h of trauma. Central cord syndrome (CCS) was defined as the upper-extremity ASIA motor score being at least 10 points lesser than the lower-extremity motor score. RESULTS: The study included 122 patients with a mean age of 65.1 years. Comparing mild (AIS grades C or D) and severe (AIS grades A or B) neurological deficits revealed that the former was independently associated with ground-level falls, OALL, and absence of prevertebral T2 high-intensity area on MRI. Although 39% of patients with SCIWORA exhibited OPLL as an etiology of cervical stenosis, OPLL demonstrated no significant effect on the severity of neurological deficits. CCS occurrence was independently associated with OALL and a larger cross-sectional cord area on MRI. Patients with OALL had significantly higher lower-extremity ASIA motor scores than those without OALL. CONCLUSIONS: OALL was significantly associated with mild neurological deficits in the lower extremities and with the occurrence of CCS after SCIWORA.

Ossification of Posterior Longitudinal Ligament in Cervical Spine and Its Association With Ossified Lesions in the Whole Spine: A Cross-Sectional Study of 2500 CT Scans.

STUDY DESIGN: A retrospective study. OBJECTIVE: To identify the prevalence and characteristics of ossified posterior longitudinal ligament (OPLL) in the cervical spine and its association with other spinal ligament ossifications. METHOD: This study is a retrospective review of whole spine CT scans of polytrauma patients from 2009 to 2018. Patients were screened for cervical OPLL (C-OPLL), thoracolumbar OPLL, thoracic ossified ligamentum flavum (OLF), cervical and thoracolumbar ossified anterior longitudinal ligament (C-OALL AND T-L OALL), ossified nuchal ligament (ONL) and, diffuse idiopathic skeletal hyperostosis (DISH) using CT scans. Their prevalence and distributions were assessed using statistical tools. Chi-square tests were used to determine statistical association between the categorical parameters. RESULTS: Out of 2500 patients, 128 had C-OPLL with a prevalence rate of 5.12% with mean age of 55.89 year. The most commonly affected level was C5, followed by C6, and C4. The segmental OPLL was highest in number (77.7%), followed by localized type (14.8%). While the prevalence rate of thoracic OPLL was 0.56%, OLF was 9.9%. Ossifications that coexisted along with C-OPLL were thoracic OPLL (7.81%), thoracic OLF (36.71%), cervical OALL (29.68%), thoracolumbar OALL (37.5%), DISH (27.34%) and, ONL (7.03%). CONCLUSION: Our study indicated a prevalence rate of 5.12% for C-OPLL with a predominance of segmental OPLL (77.7%). Among these patients, approximately 36% had coexisting thoracic OLF. In patients with symptomatic OPLL induced cervical myelopathy, MRI analysis of whole spine with relevant CT correlation may help in detecting additional ossification sites of compression.

Diffuse Idiopathic Skeletal Hyperostosis (DISH): New evidence from micro-XCT scanning.

OBJECTIVE: To observe and describe the development and underlying structure of the spinal manifestations of individuals osteologically diagnosed with DISH (Diffuse Idiopathic Skeletal Hyperostosis), using micro-XCT imaging. MATERIALS: A total of 72 individuals with DISH were identified in two modern skeletal collections in South Africa. METHODS: Vertebral columns affected by DISH were scanned at the micro-focus x-ray computed tomography facility at the Nuclear Energy Corporation of South Africa. Four features were macroscopically examined: (1) the origin of the new bone growth; (2) retention of the original vertebral cortex at the site of the new bone formation associated with DISH; (3) evidence of trabecular bone with or without sclerosis on the anterolateral surface of affected vertebrae; and (4) abnormal areas of osteosclerosis beyond features associated with DISH. RESULTS: Considerable variation across and between the four recorded features was found. Of note, 81% (n = 58) of individuals had both developed trabecular bone within the flowing new bone formation (feature 3), without retention of the original vertebral cortex (feature 2). CONCLUSIONS: Possible localised erosive/inflammatory processes destroyed the original cortex of the vertebral body and resulted in the expansion of trabeculae with new bone formation. SIGNIFICANCE: Micro-XCT imaging shed new light on the development of DISH, adding to literature suggesting that it could be an inflammatory disease. LIMITATIONS: Clinical histories of the individuals were not known. SUGGESTIONS FOR FURTHER RESEARCH: The role of chronic inflammatory disease in the development of DISH should be further explored including both the extra-spinal and spinal manifestations.

Evaluation of subjective anterior disc space widening on trauma cervical spine CT as a potential sign of ligamentous injury.

INTRODUCTION: MRI is commonly accepted as the gold standard imaging technique for identification of isolated discoligamentous injury to the cervical spine. Widening of the anterior disc space (ADW) has been suggested as signs of injury to the anterior longitudinal ligament (ALL). The purpose of this study aimed to assess the accuracy of ADW reported on CT as a sign of ligamentous injury compared. METHODS: The study was performed at a level 1 trauma centre. All patients over a 5-year period from 1 January 2015 to 31 January 2019 who underwent a cervical CT scan for the indication of trauma and who subsequently received a cervical spine MRI during the same admission were included if no fracture was found on the initial CT. Demographic data were collected along with mechanism of injury and time period between CT and MRI. Presence or absence of subjective CT-ADW along with presence or absence of ALL injury on MRI was recorded by retrospective review of the radiology reports. Sensitivity, specificity and positive and negative predictive values were then calculated. RESULTS: Over a 5-year period, 1,305 patients fulfilled the study criteria. CT-ADW had a sensitivity, specificity and positive predictive value of 8.2% (95% CI: 2.7-18.1%), 96.2% (95% CI: 95.3-97.4%) and 10.2% (95% CI: 3.4-22.2%) respectively. CONCLUSION: Subjective CT-ADW is a poor predictor of ALL injury as assessed by MRI and should not be relied upon in isolation to diagnose ligamentous injury of the cervical spine in the setting of trauma.

Anterior column realignment (ACR) for focal kyphotic spinal deformity using an anterior to psoas approach and anterior longitudinal ligament release.

Background: The anterior-to-psoas (ATP) approach to the lumbar spine has been proposed as an alternative to the transpsoas approach for approaching the disc space without dissecting through the psoas muscle, thus decreasing the risk of injury to the lumbar plexus. There are no prior studies that evaluates the clinical application of anterior longitudinal ligament (ALL) release and anterior column realignment (ACR) using the ATP approach. The objective of this study was to describe and evaluate the safety of ACR using an ATP approach with release of both the ALL and bilateral annulus for correction of a focal kyphotic lumbar deformity. Methods: A retrospective analysis of fourteen consecutive patients at a single institution between January 2017 and December 2019 of patients undergoing ACR using an ATP approach for lumbar flatback syndrome with focal kyphotic lumbar deformity by a single surgeon was performed. Primary outcome measures were pre- and postoperative radiographic parameters. Secondary outcome measures were perioperative adverse events (AEs), 30-day readmissions/reoperations, discharge disposition, post-operative length of stay (LOS), and radiographic complications. Results: Fourteen consecutive patients (mean age 67.0±3.9 years, 8 males, 6 females) with 15 total ACR levels were included in the study. A grade 1 posterior column osteotomy (PCO) with posterior instrumentation was performed at all ACR levels. L2-L3 ACR was performed in nine patients, L3-L4 in four patients, and L4-L5 in two patients. Mean preoperative disk lordotic angle at the ACR level was 5.4°±5.9° of kyphosis. Mean increase in postoperative disk lordotic angle was 24.0°±8.5° at a mean follow-up of 34.0±23.4 months. Conclusions: ACR can be performed with a complete ALL release under direct visualization using the ATP approach. This technique can be a safe and effective method for achieving substantial correction of a focal kyphotic deformity within the lumbar spine.

Spontaneous Chalk-Stick Fracture in Ankylosing Spondylitis: A Case Report.

Ankylosing spondylitis (AS) is an inflammatory disease affecting mainly the sacroiliac joints and the spine. In long-standing disease, the fused spine of AS patients is susceptible to spinal fractures, even after low impact trauma. We present a 61-year-old man with long-standing AS who presented with anterior and posterior longitudinal ligament rupture and T12 and L1 vertebral endplates fractures (a so called "chalk-stick fracture") without reporting any prior trauma and discuss relevant issues.

Surgical Intervention of Dysphagia Caused by Ossification of Anterior Longitudinal Ligament: A Case Report.

Ossification of the anterior longitudinal ligament (OALL) in the cervical spine is a common entity but rarely causes dysphagia, dyspnea, and dysphonia. We report an OALL case which causes such symptoms. A 47-year-old female patient had a complaint of progressive difficulty swallowing for 2 months. A cervical X-ray and computerized tomography scan were taken afterward, which showed OALL at the C3-7 level. She then had esophageal endoscopy to rule out other dysphagia-related disorders. The patient underwent anterior osteotomy via anterior cervical approach with significant relief of dysphagia postoperatively. Surgical management in symptomatic OALL improves dysphagia and prevents its secondary complications.

Anterior Longitudinal Ligament Flap Technique: Description of Anterior Longitudinal Ligament Opening During Anterior Lumbar Spine Surgery and Review of Vascular Complications in 189 Patients.

BACKGROUND: One of the main concerns of anterior lumbar spine approaches are vascular complications. The aim of our study is to provide technical details about a flap technique using the anterior longitudinal ligament (ALL) when approaching the lumbar spine via an anterior corridor. This can help decrease complications by protecting the adjacent vascular structures. We also include a retrospective cohort review. METHODS: This is a retrospective bicentric study: 189 patients with a mean age of 44.2 years underwent anterior lumbar spine surgery using the ALL flap technique. Patients were diagnosed with degenerative pathologies. We treated 239 lumbar levels primarily at the L4-5 and L5-S1: 88 single-level anterior lumbar interbody fusions, 9 two-level ALIFs, 51 total disk replacements (TDR), and 41 hybrid constructs (i.e., ALIF L5S1 and TDR L4L5). Anterior approaches were performed by two senior spine surgeons. The ALL flap technique was utilized in all of these cases, by carefully dissecting the ALL, with the flap suspended using sutures. As such, this ALL flap provided a "safe corridor" to avoid any potential vascular laceration. RESULTS: The operative and early surgical complication rate was 3.2%. There was no arterial injury. There were only 2 minor venous lacerations (1.05%). No blood transfusion was required. Neither lacerations happened during disk space preparation. CONCLUSIONS: Here, we provide technical details about a simple and reproducible technique using the ALL as a flap, which may help spine surgeons minimize vascular injuries during ALIF or even TDR surgeries.

Thoracic and lumbar spine trauma classification systems fail to predict post-traumatic kyphotic deformity.

Background: Post-traumatic kyphosis of the thoracic and lumbar spine can lead to pain and decreased function. MRI has been advocated to assess ligament integrity and risk of kyphosis. Methods: All thoracic and lumbar spine MRI performed for evaluation of trauma over a 3-year period at a single institution were reviewed. Patients were included if there was an MRI showing a vertebral body fracture and follow-up radiographs. Two observers retrospectively reviewed all radiographs, CT and MRI scans, and classified injuries based on the Denis, TLICS, AO and load sharing classification systems. Change in kyphosis between injury and follow-up studies was measured. The initial radiology reports made at time of patient injury were compared to the retrospective interpretations. Results: There were 67 separate injuries in 62 patients. Kyphosis measuring ≥ 10° developed despite an intact PLC in 6/14 nonoperative cases, and 3/7 surgically treated cases; when PLC was partially injured, it developed in 6/10 cases (8 treated nonoperatively, 2 treated operatively. Thirty injuries had complete disruption of PLC by MRI, 24 treated with fusion. Kyphosis ≥ 10° developed in 3/6 treated nonoperatively, and 8/24 treated with fusion. Development of kyphosis was independent of degree of vertebral body comminution. It developed equally in patients with Grade 2 and Grade 3 Denis injuries. It developed in patients with intact PLC when multiple vertebrae were involved and/or there was compressive injury to anterior longitudinal ligament (ALL). There was high interobserver variability in assessment of severity of ligamentous injury on MRI. Conclusions: Classification systems of thoracic and lumbar spine injury and integrity of the PLC failed to predict the risk of development of post-traumatic kyphotic deformity.

Anterior longitudinal ligament release from a posterior approach: an alternative to three-column osteotomy.

PURPOSE: Expansion of the anterior column and compression of the posterior column restores lordosis and sagittal imbalance. Anterior longitudinal ligament (ALL) release has been described from lateral and anterior approaches as a technique to improve lumbar lordosis; however, posterior approach to release the ALL has not been adequately assessed. METHODS: We demonstrate a case series of ALL release using a posterior approach performed in conjunction with posterior column osteotomy (PCO), with or without transforaminal lumbar interbody fusion (TLIF) for spinal deformity. Eleven cases were identified from billing records between 2010 and 2019. Retrospective review was conducted for perioperative complications and revision surgery. Overall and segmental lumbar lordosis (LL) correction was measured from pre- and postoperative imaging. RESULTS: Eleven patients underwent ALL release with a PCO. Kyphosis, scoliosis, and flat back syndrome were the most common spinal deformities. On average, patients had 9 ± 3 levels fused and a single level ALL release. ALL release was most commonly performed at L1-L2 and L2-L3 levels. An overall LL correction of 28.6° ± 19.8o was achieved; ALL release introduced 16.7° ± 11.9° of lordotic correction and accounted for 49.2 ± 30.4% of the overall lordotic correction. Average blood loss was 1030 ± 573 mL. CONCLUSIONS: ALL release as an adjunct to PCO and TLIF is a viable technique for providing increased deformity correction without subjecting the patient to a more invasive three-column osteotomy. While this approach may not be appropriate for all patients, it represents a useful option in spinal deformity correction while limiting blood loss and additional anterior surgery. LEVEL OF EVIDENCE: IV.

Association between obesity and ossification of spinal ligaments in 622 asymptomatic subjects: a cross-sectional study.

INTRODUCTION: Previous studies on patients with symptoms of spinal ligament ossification, including ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum (OLF), have not clarified whether obesity is a cause or consequence of these diseases and were limited by selection bias. Thus, we investigated the association between obesity and the prevalence of spinal ligament ossification in randomly selected asymptomatic subjects. MATERIALS AND METHODS: Between April 2020 and March 2021, 622 asymptomatic Japanese subjects who underwent computed tomography of neck to pelvis for medical check-up purposes were included. All subjects were divided into the following three groups: normal weight (body mass index [BMI] < 25 kg/m2), obese I (25 ≤ BMI < 30 kg/m2), and obese II (BMI ≥ 30 kg/m2). The relationship between factors affecting the presence of each spinal ligament ossification was evaluated using multivariate logistic regression analysis. RESULTS: The proportion of subjects with thoracic OPLL was significantly higher in the obese II group than in the other two groups (vs. normal weight, P < 0.001; vs. obese I, P < 0.001). BMI was associated with the prevalence of OLF, cervical OPLL, thoracic OPLL, and ossification of the anterior longitudinal ligament (OALL). BMI was most significantly associated with the prevalence of thoracic OPLL (ß, 0.28; 95% confidence interval, 0.17-0.39). CONCLUSION: BMI was associated with the prevalence of OALL, cervical OPLL, thoracic OPLL, and OLF in asymptomatic subjects, suggesting that obesity is associated with the development of heterotopic ossification of the spinal ligaments.

Hyperkyphosis is not dependent on bone mass and quality in the mouse model of Marfan syndrome.

Marfan syndrome (MFS) is an autosomal dominant disease affecting cardiovascular, ocular and skeletal systems. It is caused by mutations in the fibrillin-1 (FBN1) gene, leading to structural defects of connective tissue and increased activation of TGF-ß. Angiotensin II (ang-II) is involved in TGF-ß activity and in bone mass regulation. Inhibition of TGF-ß signaling by blockage of the ang-II receptor 1 (AT1R) via losartan administration leads to improvement of cardiovascular and pulmonary phenotypes, but has no effect on skeletal phenotype in the haploinsufficient mouse model of MFS mgR, suggesting a distinct mechanism of pathogenesis in the skeletal system. Here we characterized the skeletal phenotypes of the dominant-negative model for MFS mgΔlpn and tested the effect of inhibition of ang-II signaling in improving those phenotypes. As previously shown, heterozygous mice present hyperkyphosis, however we now show that only males also present osteopenia. Inhibition of ang-II production by ramipril minimized the kyphotic deformity, but had no effect on bone microstructure in male mutant animals. Histological analysis revealed increased thickness of the anterior longitudinal ligament (ALL) of the spine in mutant animals (25.8 ± 6.3 vs. 29.7 ± 7.7 µm), coupled with a reduction in type I (164.1 ± 8.7 vs. 139.0 ± 4.4) and increase in type III (86.5 ± 10.2 vs. 140.4 ± 5.6) collagen in the extracellular matrix of this ligament. In addition, we identified in the MFS mice alterations in the erector spinae muscles which presented thinner muscle fibers (1035.0 ± 420.6 vs. 655.6 ± 239.5 µm2) surrounded by increased area of connective tissue (58.17 ± 6.52 vs. 105.0 ± 44.54 µm2). Interestingly, these phenotypes were ameliorated by ramipril treatment. Our results reveal a sex-dependency of bone phenotype in MFS, where females do not present alterations in bone microstructure. More importantly, they indicate that hyperkyphosis is not a result of osteopenia in the MFS mouse model, and suggest that incompetent spine ligaments and muscles are responsible for the development of that phenotype.