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Abstract Background Andersen’s lesion (AL) is a rare complication of ankylosing spondylitis (AS), characterized by nonneoplastic bone destruction, typically manifested as bone destruction and sclerosis in the vertebral body and/or intervertebral disc area. At present, there is no consensus on the pathology and etiology of AL. Repeated trauma, inflammation in essence and part of the natural history of Ankylosing spondylitis itself are the most widely recognized theories of the etiology of AL. However, positive bacteria cultured in bone biopsy of Andersen’s lesion (AL) in Ankylosing spondylitis patients are extremely rare. Herein, we report a rare case of detecting Ewingella americana from a patient with Andersson lesion in ankylosing spondylitis by Metagenomic Next-Generation Sequencing (mNGS) Test. Case presentation This case involved a 39-year-old male with a history of AS for 11 years, who developed AL (T11/12) in the thoracic vertebrae. After sufficient preoperative preparation, we successfully performed one-stage posterior approach corrective surgery and collected bone biopsies samples for examination. Cultured bacteria were not found, and pathological histology indicated infiltration of inflammatory cells. However, it is worth noting that we discovered a gram-negative bacterium, the Ewingella americana, through mNGS testing. Further histopathological examination suggests chronic inflammatory cell infiltration. After one-stage posterior approach corrective surgery, the patient’s condition significantly improved. At the 6-month follow-up, the pain significantly decreased, and the patient returned to normal life. Conclusion We detected Ewinia americana in the bone biopsies of Andersson lesion (AL) in ankylosing spondylitis patient by mNGS.

Background: Andersen's lesion (AL) is a rare complication of ankylosing spondylitis (AS), characterized by nonneoplastic bone destruction, typically manifested as bone destruction and sclerosis in the vertebral body and/or intervertebral disc area. At present, there is no consensus on the pathology and etiology of AL. Repeated trauma, inflammation in essence and part of the natural history of Ankylosing spondylitis itself are the most widely recognized theories of the etiology of AL. However, positive bacteria cultured in bone biopsy of Andersen's lesion (AL) in Ankylosing spondylitis patients are extremely rare. Herein, we report a rare case of detecting Ewingella americana from a patient with Andersson lesion in ankylosing spondylitis by Metagenomic Next-Generation Sequencing (mNGS) Test. Case presentation: This case involved a 39-year-old male with a history of AS for 11 years, who developed AL (T11/12) in the thoracic vertebrae. After sufficient preoperative preparation, we successfully performed one-stage posterior approach corrective surgery and collected bone biopsies samples for examination. Cultured bacteria were not found, and pathological histology indicated infiltration of inflammatory cells. However, it is worth noting that we discovered a gram-negative bacterium, the Ewingella americana, through mNGS testing. Further histopathological examination suggests chronic inflammatory cell infiltration. After one-stage posterior approach corrective surgery, the patient's condition significantly improved. At the 6-month follow-up, the pain significantly decreased, and the patient returned to normal life. Conclusion: We detected Ewinia americana in the bone biopsies of Andersson lesion (AL) in ankylosing spondylitis patient by mNGS. [ABSTRACT FROM AUTHOR]

Background: Andersson lesion (AL), also known as aseptic spondylodiscitis, is a pathological condition characterized by a destructive lesion in the vertebral or discovertebral region. The aim of this study was to assess functional, radiological, and neurological outcome of midline posterior surgery with transfacetal/transpedicular decompression and long-segment instrumentation and fusion in all patients with AL. Materials and Methods: A total of 36 consecutive patients with AL with or without neurodeficit were managed with midline posterior approach with long-segment fixation, decompression and anterior vertebral reconstruction added by same midline approach. The demographic data, visual analogue scale (VAS), modified Oswestry Disability Index (mODI), ankylosing spondylitis quality of life (ASQoL), local and global kyphosis angle, Frankel neurological grade, blood loss, duration of surgery, perioperative complications, and fusion rate were compiled and assessed. Results: The mean age of the patients was 52 years (26 males and 10 females). Among the patients, 9 patients had thoracic, 25 patients had thoracolumbar, and 2 patients had lumbar vertebral involvement. All patients in the study achieved fusion at final follow-up period of 24 months. The mean duration of hospital stay, intraoperative blood loss, and surgery duration was 6.17 days, 252 mL, and 130 min, respectively. VAS improved from mean 7.69 ± 0.98 to 1.67 ± 0.72, mODI from mean 70.28 ± 3.55 to 21.14 ± 2.13, ASQoL from mean 14.22 ± 1.59 to 7.17 ± 1.25, local kyphosis from 23.61 ± 1.67 to 18.52 ± 1.05, and global kyphosis from 57.02 ± 0.72 to 36.16 ± 1.23, leading to better sagittal balance. Except two patients all had full neurological recovery. Conclusions: Posterior midline approach with long-segment instrumentation and anterior decompression by transpedicular/transfacetal approach and bone grafting with selective use of cages can give satisfactory results with excellent fusion rates and good functional outcomes.

Background Andersson lesion (AL) refers to a destructive vertebral or disco‐vertebral lesion of the spine in patients with ankylosing spondylitis (AS). Against the backdrop that the best surgical option for AL remains controversial, this work serves as the first case report of oblique lateral interbody fusion (OLIF) combined with posterior pedicle screw fixation to treat AL of the lumbar spine under minimal invasion. Case presentation In this case report, the patient involved was a female aged 37 diagnosed with AL (L3‐L4). OLIF combined with pedicle screw fixation was carried out to achieve stabilization of the lumbar spine. It turned out that the patient experienced significant pain relief in her excellent post‐operative recovery, with her post‐surgical radiographs indicating good stability and bony fusion. The patient now remains disease‐free with no low back pain or neurological deficit at the two‐year follow‐up. Conclusion OLIF combined with pedicle screw fixation thus has proven to be an ideal therapeutic option for treating AL of the lumbar spine.

BACKGROUND: Andersson lesion (AL) is a rare complication of ankylosing spondylitis (AS). Its clinical outcome of surgical treatment needs further exploration. OBJECTIVE: To evaluate the clinical and radiological outcomes of transforaminal thoracolumbar intervertebral fusion (TTIF) in the treatment of AS patients with thoracolumbar AL. METHODS: Fourteen patients with thoracolumbar AL who suffered from back pain, spinal instability or kyphotic deformity were retrospectively recruited. The clinical outcomes were evaluated with Visual Analog Scale (VAS) and Oswestry Disability Index (ODI). Radiological outcomes were measured with local kyphotic (LK) angle and general kyphotic (GK) angle. RESULTS: Before surgical treatment for the AL patients, their VAS score and ODI score was 8.0 ± 0.2 and 64.0 ± 6.9, respectively. After TTIF surgery, VAS score of the patients was improved to 2.4 ± 0.5 (p < 0.01) and ODI score was decreased to 17.0 ± 3.7 (p < 0.01). One patient with neurological deficit showed an improvement in the Frankel grade from C to D and all others were grated E-level before and after surgery. For radiological outcomes, patients' LK angle was reduced from 18.5 ± 7.2 to 11.0 ± 6.4 (p < 0.01) and GK angle was reduced to 38.6 ± 8.8 from 42.8 ± 10.4 (p < 0.01) at the 1-year follow-up. CONCLUSION: For AS patients with thoracolumbar AL, we propose that TTIF is an effective and safe operative treatment, which can achieve good fusion, satisfactory radiological and clinical outcomes. [ABSTRACT FROM AUTHOR]

Spinal angiolipomas (SALs) are very rare benign extradural neoplasms, representing 0.14%–1.2% of all spinal tumors. Andersson lesion is a localized vertebral or disco-vertebral lesion in ankylosing spondylitis. Co-occurrence of these lesions is very rare and has never been reported. We are reporting one such case of a 61-year-old man presented with features of dorsal compressive myelopathy. On magnetic resonance imaging (MRI), he was diagnosed to have a SAL at D6–D9 and Andersson lesion at D7–D8 and L1–L2. He was managed surgically with a long-segment fixation and decompression and gross total excision of the tumor. Diagnosis of a SAL was confirmed in a biopsy, and postoperatively, he showed good clinical improvement. In conclusion, given the rarity of co-occurrence of these pathologies, a strong clinical suspicion is required. MRI and CT scan help in diagnosis. Both these pathologies warrant surgical management. When diagnosed early and managed appropriately, they have a good prognosis.

Study objective: Due to the rarity of the Andersson lesion (AL), the literature is ambiguous regarding the type of surgical fixation, need for debridement and deformity correction. The purpose of this retrospective study is to evaluate the efficacy, feasibility and functional outcome of posterior fixation in AL. Materials and methods: This study included 35 patients having thoracolumbar AL operated for in situ fixation and fusion with minimum of 24-month follow-up. VAS (Visual Analogue Score) back pain, ODI (Oswestry Disability Index), Frankel's grade were compared and analyzed. Union status was noted with complications. Results: The mean age of 35 patients was 56.34(± 11.3) years with average follow-up of 51.49 months. Two patients had AL at two levels. 27/37 AL were at discal level. Average estimated blood loss (EBL) was 276.43 ml and duration of surgery was 130.43 min. On an average, operated segments needed 7.77 screws. There were ten minor complications without long-term sequel. Neurological improvement was noted in 30 patients. Average preoperative VAS score improved from 8.69 to 3.14, ODI score improved from 68.76 to 18.77 at final follow-up which were significant (p < 0.05). There was significant improvement in Frankel's grading (Z = − 4.354, P = 0.00). Conclusions: Surgical management of AL by posterior approach and posterior stabilization can give satisfactory results without the need of extensive anterior reconstruction, bone grafting or deformity correction procedures without added morbidity and complications. [ABSTRACT FROM AUTHOR]

Background: Andersson lesion (AL) refers to a destructive vertebral or disco‐vertebral lesion of the spine in patients with ankylosing spondylitis (AS). Against the backdrop that the best surgical option for AL remains controversial, this work serves as the first case report of oblique lateral interbody fusion (OLIF) combined with posterior pedicle screw fixation to treat AL of the lumbar spine under minimal invasion. Case presentation: In this case report, the patient involved was a female aged 37 diagnosed with AL (L3‐L4). OLIF combined with pedicle screw fixation was carried out to achieve stabilization of the lumbar spine. It turned out that the patient experienced significant pain relief in her excellent post‐operative recovery, with her post‐surgical radiographs indicating good stability and bony fusion. The patient now remains disease‐free with no low back pain or neurological deficit at the two‐year follow‐up. Conclusion: OLIF combined with pedicle screw fixation thus has proven to be an ideal therapeutic option for treating AL of the lumbar spine. [ABSTRACT FROM AUTHOR]

Study Design This retrospective study was conducted including 18 patients who underwent posterior-only stabilization and fusion procedure for pseudoarthrosis in the ankylosed spine from October 2007 to May 2015. Purpose This study aimed to describe the treatment outcomes in 18 patients with Andersson lesion (AL) who were managed using the posterior-only approach. Literature Review AL is an unstable, localized, vertebral, or discovertebral lesion of the spine. It is observed in patients with ankylosing spondylitis. The exact etiology of this disorder remains unclear, and the treatment guidelines are not clearly described. Methods We analyzed 18 patients with AL who were treated with posterior long segment spinal fusion without any anterior interbody grafting or posterior osteotomy. Pre- and postoperative radiography, computed tomography, and recent follow-up images were examined. The pre- and postoperative Visual Analog Scale score and the Oswestry Disability Index score were evaluated for all patients. Whiteclouds’ outcome analysis criteria were applied at the follow-up. Moreover, at study completion, patient feedback was collected; all the patients were asked to provide their opinion regarding the surgery and were asked whether they would recommend this procedure to other patients and them self undergo the same procedure again if required. Results The most common site was the thoracolumbar junction. The symptom duration ranged from 1 month to 10 years preoperatively. Most patients experienced fusion by the end of 1 year, and the fusion mass could be observed as early as 4 months. Pseudoarthrosis void of up to 2.5 cm was noted to be healed in subsequent imaging. In addition, clinically, the patients reported good symptomatic relief. No patient required revision surgery. Whiteclouds’ outcome analysis score at the latest follow-up revealed good-to-excellent outcomes in all patients. Conclusions ALs can be treated using the posterior-only approach with long segment fixation and posterior spinal fusion. This is a safe, simple, and quick procedure that prevents the morbidity of anterior surgery.

Andersson lesion (AL) is not a rare complication of ankylosing spondylitis (AS), but it seldom occurs in single lumbosacral segments or young people. We present a case of a young patient with AS and AL between L5 and S1. A 30-year-old man with a history of AS presented with AL between L5 and S1. Surgery performed under O-arm navigation was successful. At 6-month follow-up, the patient's pain was reduced, and his function had improved. AL rarely occurs in the lumbosacral region or in young people and can be misdiagnosed as spinal tuberculosis. Surgical treatment of AL aims to relieve spinal nerve compression, reconstruct spinal stability, and restore sagittal balance. In view of the ambiguous anatomic landmark of patients with AS, we recommend surgery assisted with O-arm navigation, which clearly showed the entry point and guaranteed the accuracy of pedicle screw placements. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the clinical efficacy of Andersson lesion (AL) treatments and prognostic factors using medium‐ to long‐term follow‐up data and discuss the clinical characteristics and treatment of AL. Forty‐eight consecutive AL cases at our center from June 2011 to March 2018 were retrospectively analyzed, including 13 cases treated conservatively and 35 treated surgically. Epidemiological characteristics, treatment modalities, clinical features and outcomes, and prognostic factors of the Japanese Orthopaedic Association (JOA) recovery rate were reviewed. Neurological functional recovery was evaluated by American Spinal Injury Association (ASIA) classification. Clinical efficacy was evaluated by JOA score, visual analog scale (VAS) score, and Cobb's angle. The mean overall follow‐up duration was 44.5±18.5 months (range, 27–85 months). There were 36 male and 12 female patients, with a mean age of 49.4±13.1 years (range, 26–72 years). The most common lesion location was the thoracolumbar region, i.e., T10‐L2 (n=33; 68.8%), followed by the thoracic (n=10) and lumbar (n=5) regions. Patients treated surgically showed significantly better JOA scores, VAS scores and Cobb's angles at the final follow‐up than did patients treated conservatively (P<.05). Univariate and binary logistic regression analyses identified two prognostic factors of the JOA score recovery rate: treatment modality (OR=0.157; 95%CI, 0.028–0.89; P=.036) and bone fusion (OR=9.965; 95%CI, 2.052–48.387; P=.004). Conservative treatment and bone nonunion predict worse JOA score recovery. Surgery remains the optimal treatment for AL in ankylosing spondylitis patients, with better clinical efficacy demonstrated by medium‐ to long‐term follow‐up data. [ABSTRACT FROM AUTHOR]

Introduction/objectives: This study was to investigate the role of pelvic incidence (PI) in the development of Andersson lesions (ALs) in ankylosing spondylitis (AS) patients with kyphosis and to evaluate the difference in sagittal spinopelvic parameters between inflammatory ALs and mechanical ALs. Method: A total of 135 AS patients with kyphosis were reviewed. The patients were classified into AL group and non-AL group based on the presence or absence of ALs. Additionally, AS patients with ALs were also classified as either inflammatory or mechanical lesions depending on the radiological features of the lesions. The sagittal spinopelvic parameters of all these AS patients were measured and compared. Logistic regression analysis was performed to determine the powerful variables for predicting ALs in AS patients. Results: ALs were detected in 34 patients (25.2%) of the total 135 AS patients. The mean PI of the AL group was 40.0°, which was significantly lower than that (48.3°) of the non-AL group (P < 0.001). No statistically significant difference was observed in PI (P = 0.350) between the inflammatory lesion group and the mechanical lesion group. Logistic regression analysis showed that only PI was a statistically significant risk factor for ALs (P < 0.001) and was negatively correlated with ALs (odds ratio = 0.76). Conclusions: These data suggest that low PI is closely associated with ALs in AS patients with kyphosis and that it might be a possible risk factor for the development of ALs. Moreover, both inflammatory and mechanical ALs patients had similarly low PI. Key Points • Low PI was closely associated with ALs in AS patients with kyphosis and might be a possible risk factor for development of ALs. • Either inflammatory or mechanical ALs patients had similar low PI. [ABSTRACT FROM AUTHOR]

Study DesignRetrospective case series.PurposeTo assess safety and efficacy of single stage, posterior stabilisation and anterior cage reconstruction through the transforaminal or lateral extra-cavitary route for Andersson lesions.Overview of LiteraturePseudoarthrosis in ankylosing spondylitis (Andersson lesion, AL) can cause progressive kyphosis and neurological deficit. Management involves early recognition and surgical stabilisation in patients with instability. However, the need and safety of anterior reconstruction of the vertebral body defect remains unclear.MethodsTwenty consecutive patients with AL whom presented with instability back pain and or neurological deficit were managed by single stage posterior approach with long segment pedicle screw fixation and anterior vertebral reconstruction. Radiological evaluation included- the regional kyphotic angle, measurement of anterior defect in computed tomography (CT) scan and the spinal cord status in magnetic resonance imaging. Radiological outcomes were assessed for fusion and kyphosis correction. Functional outcomes were assessed with visual analogue scale (VAS), ankylosing spondylitis quality of life (ASQoL) and Oswestry disability index (ODI).ResultsThe mean age of the patients was 50.1 years (male, 18; female, 2). The levels affected include thoracolumbar (n=12), lower thoracic (n=5) and lumbar (n=3) regions. The mean level of fixation was 6.2±2.4 vertebrae. The mean anterior column defect was 1.6±0.6 cm. The mean surgical duration, blood loss and hospital stay were 112 minutes, 452 mL and 6.2 days, respectively. The mean followup was 2.1 years. At final follow up, VAS for back pain improved from 8.2 to 2.4 while ODI improved from 62.7 to 18.5 (p

Abstract Background Andersson lesion is a well-known complication in ankylosing spondylitis. Recently, owing to the worry about the healing of fracture, some scholars advocated additional anterior surgery or other procedures were necessary, which increase the risk of the nerve injury. The purpose of this study is to introduce our experience and to explore the efficacy and feasibility of posterior wedge osteotomy and debridement through Andersson Lesion for surgical treatment of severe kyphosis in ankylosing spondylitis. Methods From January 2012 to January 2014, a retrospective study of 14 Andersson lesion patients with severe kyphosis in ankylosing spondylitis treated with surgery was completed with an at least 2-year follow-up. The debridement procedure, before posterior wedge osteotomy in posterior approach, must scrape all sclerosis bone until healthy cancellous bone appears. Radiographic and clinical results and complications were assessed with an average follow-up of 24 months. The CT scan was obtained preoperatively and at the final follow-up to assess the displacement of the fracture preoperatively, the safety of screw insertion, the healing of the fracture at the final follow-up. The Bridwell interbody fusion grading system was used to assess the healing of the fracture. Results Local kyphosis was substantially corrected from 51.7 ± 15.6 to 7.1 ± 19.5, with a mean correction of 44°. The global kyphosis (GK) changed from 60.6 ± 28.3 to 20.3 ± 10.3 (P = 0.000). The mean VAS back pain scores decreased from 6.7 ± 0.8 preoperatively to 0.75 ± 0.6 after a 2-year follow-up (P = 0.000). The ODI score improved from 60.56 ± 15.1% preoperatively to 23.46 ± 8.2% after a 2-year follow-up (P = 0.000). The CT scan showed solid fusion at the level of the AL, and no internal fixation loose. All patients achieved grade 1 fusion. No major complication occurred. Conclusions The posterior wedge osteotomy and debridement through AL can be used to correct the severe kyphosis in ankylosing spondylitis, achieving favorable clinical outcomes, good fusion, and satisfactory deformity correction.

Study Design: Retrospective case series. Purpose: To assess safety and efficacy of single stage, posterior stabilisation and anterior cage reconstruction through the transforaminal or lateral extra-cavitary route for Andersson lesions. Overview of Literature: Pseudoarthrosis in ankylosing spondylitis (Andersson lesion, AL) can cause progressive kyphosis and neurological deficit. Management involves early recognition and surgical stabilisation in patients with instability. However, the need and safety of anterior reconstruction of the vertebral body defect remains unclear. Methods: Twenty consecutive patients with AL whom presented with instability back pain and or neurological deficit were managed by single stage posterior approach with long segment pedicle screw fixation and anterior vertebral reconstruction. Radiological evaluation included- the regional kyphotic angle, measurement of anterior defect in computed tomography (CT) scan and the spinal cord status in magnetic resonance imaging. Radiological outcomes were assessed for fusion and kyphosis correction. Functional outcomes were assessed with visual analogue scale (VAS), ankylosing spondylitis quality of life (ASQoL) and Oswestry disability index (ODI). Results: The mean age of the patients was 50.1 years (male, 18; female, 2). The levels affected include thoracolumbar (n=12), lower thoracic (n=5) and lumbar (n=3) regions. The mean level of fixation was 6.2±2.4 vertebrae. The mean anterior column defect was 1.6±0.6 cm. The mean surgical duration, blood loss and hospital stay were 112 minutes, 452 mL and 6.2 days, respectively. The mean follow-up was 2.1 years. At final follow up, VAS for back pain improved from 8.2 to 2.4 while ODI improved from 62.7 to 18.5 (p <0.05) and ASQoL improved from 14.3±2.08 to 7.90±1.48 (p <0.05). All patients had achieved radiological union at a mean 7.2±4.6 months. The mean regional kyphotic angle was 27° preoperatively, 16.7° postoperatively and 18.1° at the final follow-up. Conclusions: Posterior stabilisation and anterior reconstruction with cage through an all-posterior approach is safe and can achieve good results in Andersson lesions. [ABSTRACT FROM AUTHOR]

To study the diagnosis and surgical treatment of thoracic-lumbar Andersson lesions among patients with ankylosing spondylitis., Method: We retrospectively collected data from all patients with spine Andersson lesions from 2010 to 2020 and follow-up patients who received surgical treatment. One of the patients was misdiagnosed as spinal tuberculosis but was diagnosed with Andersson lesion after reviewing the patient's postoperative data., Results: There were 11 patients with Andersson lesions, three females and eight males. Four patients received conservative treatment, and six patients received posterior long-segment pedicle screw fixation, one patient received anterior lumbar fusion. One patient occurred neurologic impairment. All other patients recovered well and spine pain disappeared. There was no surgical infection., Conclusion: Andersson lesions among patients with ankylosing spondylitis could be treated with posterior long-segment pedicle screw fixation. And it should be differentiated between spine infection and spine tuberculosis., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research authorship and/or publication of this article., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

The objective of this study was to identify the characteristics of Andersson lesions using whole spine magnetic resonance imaging (MRI) compared with plain radiography in ankylosing spondylitis (AS). A total of 62 patients with AS who had undergone whole spine MRI and plain radiography were retrospectively enrolled in this study. We compared the number of discovertebral units (DVUs) with Andersson lesions with clinical and radiographic indices such as erythrocyte sediment rate (ESR), C-reactive protein (CRP), the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), and modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Fifty-three patients (85.5 %) by whole spine MRI and 23 patients (37.1 %) by plain radiography had at least one Andersson lesion. We found 129 DVUs with Andersson lesions (11.1 %) by MRI and 35 DVUs by plain radiography over all the spine levels. Andersson lesions by MRI were most commonly detected at the lower thoracic spine (from T7-8 to T12-L1). Among the 151 total Andersson lesions by whole spine MRI, 41 were identified as central disc type, 26 as anterior peripheral disc type, 44 as posterior peripheral disc type, and 40 as diffuse disc type. However, the number of Andersson lesions did not correlate with ESR, CRP, BASDAI, BASFI, or mSASSS ( p > 0.05 for all). Our study indicates that the presence of Andersson lesions in patients with AS is clearly underestimated. MRI is a superior technique for detecting early Andersson lesions compared with plain radiography. [ABSTRACT FROM AUTHOR]

Background: Andersson lesion (AL) can occur in patients with ankylosing spondylitis (AS). Surgical instrumentation and fusion is considered the principle management in symptomatic AL that fails to resolve from a conservative treatment. However, there is significant controversy over the ideal management. The purpose of this study is to introduce our experience and explore the efficacy and feasibility of transpedicular subtraction and disc resection osteotomy technique for patients with AL-complicating AS.Methods: From January 2009 to January 2013, 17 consecutive patients with Andersson lesion-complicating ankylosing spondylitis treated with transpedicular subtraction and disc resection osteotomy technique were retrospectively reviewed. All patients completed a follow-up of at least 2 years.Results: The average surgical time was 219 min with a mean intraoperative blood loss of 876 ml. The average preoperative regional angle was 29.1°, 4.9° postoperatively, and 5.9° at the final follow-up. The global angle changed from 59.1° preoperatively to 24.7° after surgery with the sagittal vertical axis (SVA) changed from 153.7 to 41.1 mm. The mean VAS back pain scores decreased from 6.4 preoperatively to 1.1 postoperatively and the ODI score improved from 50.9 preoperatively to 16.9 at the final follow-up. Solid fusion was obtained in all patients.Conclusion: The transpedicular subtraction and disc resection osteotomy achieve satisfactory kyphosis correction, good fusion and favorable clinical outcomes with less blood loss and complications than other approaches, implying an alternative method in patients with Andersson lesion-complicating ankylosing spondylitis. [ABSTRACT FROM AUTHOR]

Ankylosing spondylitis (AS) is a chronic inflammatory disease that affects especially males in the second and third decades of life. 1 The main clinical symptom is inflammatory back pain typically occurring at night and morning stiffness improving after exercise. Apart from syndesmophytes and ankylosis of the spine resulting in rigidity, in longstanding ankylosing spondylitis, also focal destructive 1 discovertebral lesions (Andersson lesions) can occur. The case we present here is of a 35 year old male patient who presented to us with the symptoms of pain of upper back and both shoulders for 6 years. Pain was followed with stiffness of the neck and shoulder. Radiography of the dorsolumbar spine revealed squaring of the vertebra, syndesmophytes, calcification of the anterior spinal ligament, end plate irregularity at D10-D11 level, ill defined sclerosis with fracture of the ankylosed spine, features consistent with Andersson lesion type III. He underwent posterior spinal fusion with good functional outcome. [ABSTRACT FROM AUTHOR]

Andersson lesions also termed as aseptic spondylodiscitis, spinal pseudoarthrosis are known to occur in patients with ankylosing spondylitis. Trauma as well as inflammation has been cited as factors responsible for the causation of these lesions. A variety of surgical approaches have been described in the literature such as anterior, posterior, combined anterior and posterior, with or without reconstruction of the anterior column defect. Controversy still exists regarding the optimal management these lesions. To address the optimal method of management, levels of instrumentation, requirement of fusion and anterior instrumentation and general epidemiological profile of the patients with Andersson lesions. An electronic search for studies on the surgical management of Andersson lesions of spine was performed. Quality assessment of the included articles was done by two independent authors according to the criteria used by researchers previously in systematic reviews. Males were found to have an increased incidence with the thoracolumbar junction being the most common level. Posterior approach was the most favoured with reconstruction of the gap in the anterior column. Posterior osteotomy with correction of deformity was done commonly for an optimal healing environment. Instrumenting 2–3 levels above and below the lesion is favoured by most. Conservative management for Andersson lesions can be employed in the setting of acute trauma and stable fractures involving a single column. Surgical management of these lesions with a posterior long segment fixation and anterior column reconstruction is the favoured treatment in majority of the cases. [ABSTRACT FROM AUTHOR]

This study reviews the presentation, etiology, imaging characteristics and reasons for missed diagnosis of Andersson lesion (AL) and analyzes the surgical results of short segment fixation in the thoracolumbar region. This is a retrospective single center study. Fourteen patients (15 lesions) who were operated for AL were analyzed. The study was designed in two parts. The first part consisted of analysis of clinical and radiological features (MRI and radiographs) to highlight, whether definitive characteristics exist. The second part consisted of analysis of outcome of short segment fixation as measured by VAS, Frankel score, AsQoL index, and union, with assessment of complications. The follow-up was 42.33 ± 19.29 months (13 males and 1 female) with a mean age of 61.13 ± 19.74 years. There was predisposing trauma in five patients. There was a delay in presentation of the patients by 5.86 ± 2.50 months. There was misdiagnosis in all the cases, at primary orthopedic level (ten cases were put on anti-tuberculous treatment due to its MRI resemblance to infection) and all but one case at radiologist level. Radiographs and MRI had characteristic features in all cases, and MRI could detect posterior element affection in 14 lesions as against only 8 posterior lesions detected in radiographs. In all patients, there was a patient's delay and/or physician's delay to arrive at a diagnosis. Spinal fusion was seen in all the cases. Outcome measures of VAS, Frankel score, and AsQoL index showed significant improvement ( P < 0.002). No major complications occurred. There is a lack of awareness of AL leading to misdiagnosis. Definite clinico-radiological features do exist in AL and short segment fixation is effective. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the prevalence of Andersson lesions (AL) in ankylosing spondylitis (AS) patients who will start anti-tumor necrosis factor (TNF) treatment. Radiographs and magnetic resonance imaging (MRI) of the spine were performed before therapy with anti-TNF. ALs were defined as discovertebral endplate destructions on MRI, associated with bone marrow edema and fat replacement or sclerosis, a decreased signal on T1, enhancement after contrast administration (gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA)), and increased signal on T2 and short tau inversion recovery (STIR). Additionally, conventional radiography showed a fracture line, irregular endplates, and increased sclerosis of adjacent vertebral bodies. Fifty-six AS patients were included, 68% males, mean age of 43 years, and mean disease duration of 11 years. The mean bath ankylosing spondylitis disease activity index was 6.4, and 24% of all patients had ankylosis. Only one patient showed a discovertebral abnormality with bone marrow edema of more than 50% of the vertebral bodies adjacent to the intervertebral disk of T7/T8 and T9/T10, a hypodense signal area on T1, and a high signal on STIR. Irregular endplates were depicted, and T1 after Gd-DTPA demonstrated high signal intensity around the disk margins. However, no fracture line was visible on conventional radiology, and therefore, this case was not considered to be an AL. No AL was detected in our AS patients, who were candidates for anti-TNF treatment. One patient showed a discovertebral abnormality on MRI, without a fracture line on conventional radiology. The relative small proportion of patients with a long-established disease might explain this finding for, particularly, an ankylosed spine is prone to develop an AL. [ABSTRACT FROM AUTHOR]

A well-known complication in patients with ankylosing spondylitis (AS) is the development of localised vertebral or discovertebral lesions of the spine, which was first described by Andersson in 1937. Since then, many different terms are used in literature to refer to these localised lesions of the spine, including the eponym ‘Andersson lesion’ (AL). The use of different terms reflects an ongoing debate on the exact aetiology of the AL. In the current study, we performed an extensive review of the literature in order to align communication on aetiology, diagnosis and management between treating physicians. AL may result from inflammation or (stress-) fractures of the complete ankylosed spine. There is no evidence for an infectious origin. Regardless of the exact aetiology, a final common pathway exists, in which mechanical stresses prevent the lesion from fusion and provoke the development of pseudarthrosis. The diagnosis of AL is established on conventional radiography, but computed tomography and magnetic resonance imaging both provide additional information. There is no indication for a diagnostic biopsy. Surgical instrumentation and fusion is considered the principle management in symptomatic AL that fails to resolve from a conservative treatment. We advise to use the term Andersson lesion for these spinal lesions in patients with AS. [ABSTRACT FROM AUTHOR]

Two cases with a long-standing thoracolumbar kyphosis due to ankylosing spondylitis are presented with a symptomatic localized destructive kyphotic lesion of the spine. Clinical and radiographic findings demonstrated a progressive vertebral and discovertebral kyphotic pseudarthrosis, known as an Andersson lesion, at the L1 and L1-2 level, respectively. Surgical correction and stabilization was performed by an extending transpedicular wedge resection osteotomy to restore spinal stability, to facilitate fracture healing as well as to restore the sagittal balance of the ankylosed spine. To predict the effect of a surgical correction of the Andersson lesion on the sagittal balance, deformity planning was performed preoperatively. The indication for surgery, the surgical technique and the 2 years’ clinical results are described. In addition, the difficulties experienced with preoperative deformity planning are evaluated. [ABSTRACT FROM AUTHOR]

We present two patients with seronegative enthesopathy and arthropathy (SEA) syndrome and Andersson lesions. Peripheral arthritis and enthesitis with or without back pain are very important in the recognition of Andersson lesion. MRI seems to be the best method for early diagnosis. [ABSTRACT FROM AUTHOR]

Competing Interests: Competing interests: None declared.

Objective: To investigate the safety and effectiveness of debridement and interbody fusion via posterior pedicle lateral approach in treatment of ankylosing spondylitis with thoracolumbar Andersson lesion (AL)., Methods: Between October 2011 and January 2017, 10 patients of ankylosing spondylitis with thoracolumbar AL were treated with debridement via posterior pedicle lateral approach and interbody fusion with bone grafting. There were 8 males and 2 females with an average age of 48.8 years (range, 31-79 years). The disease duration was 1.5-48.0 months (mean, 10.6 months). All patients were single-segment lesion, including 3 cases of T 10, 11 , 4 cases of T 11, 12 , and 3 cases of T 12 , L 1 . The preoperative visual analogue scale (VAS) score was 8.0±0.8, the Oswestry disability index (ODI) was 68.8%±5.5%, and the Cobb angle of local kyphosis was (26.3±7.1)°. According to American Spinal Injury Association (ASIA) scoring system, neurological impairment was assessed in 1 case of grade C, 4 cases of grade D, and 5 cases of grade E., Results: All the operations of 10 patients completed successfully. The operation time was 120-185 minutes (mean, 151.5 minutes), and the intraoperative blood loss was 300-750 mL (mean, 450.0 mL). Dural sac tear occurred in 1 case during operation and was repaired, with no cerebrospinal fluid leakage after operation. All patients were followed up 24-50 months (mean, 31.2 months). At last follow-up, the VAS score was 1.9±0.9 and ODI was 13.0%±3.0%, showing significant differences when compared with preoperative ones ( t =17.530, P =0.000; t =31.890, P =0.000). Neurological function was improved significantly at 24 months after operation, and rated as ASIA grade E. The Cobb angles were (12.6±4.6)° at 3 days and (13.6±4.6)° at 24 months after operation, which were significantly different from those before operation ( P <0.05); there was no significant difference between 3 days and 24 months after operation ( P >0.05). At 24 months after operation, the grafted bone obtained good fusion at AL segment. During the follow-up, there was no failure of internal fixation such as nail withdrawal, broken nail, and broken rod., Conclusion: Debridement and interbody fusion via posterior pedicle lateral approach for the ankylosing spondylitis with thoracolumbar AL can achieve satisfactory effectiveness, good fusion, and a certain correction of local kyphosis.

Study Design: This retrospective study was conducted including 18 patients who underwent posterior-only stabilization and fusion procedure for pseudoarthrosis in the ankylosed spine from October 2007 to May 2015., Purpose: This study aimed to describe the treatment outcomes in 18 patients with Andersson lesion (AL) who were managed using the posterior-only approach. Literature Review: AL is an unstable, localized, vertebral, or discovertebral lesion of the spine. It is observed in patients with ankylosing spondylitis. The exact etiology of this disorder remains unclear, and the treatment guidelines are not clearly described., Methods: We analyzed 18 patients with AL who were treated with posterior long segment spinal fusion without any anterior interbody grafting or posterior osteotomy. Pre- and postoperative radiography, computed tomography, and recent follow-up images were examined. The pre- and postoperative Visual Analog Scale score and the Oswestry Disability Index score were evaluated for all patients. Whiteclouds' outcome analysis criteria were applied at the follow-up. Moreover, at study completion, patient feedback was collected; all the patients were asked to provide their opinion regarding the surgery and were asked whether they would recommend this procedure to other patients and them self undergo the same procedure again if required., Results: The most common site was the thoracolumbar junction. The symptom duration ranged from 1 month to 10 years preoperatively. Most patients experienced fusion by the end of 1 year, and the fusion mass could be observed as early as 4 months. Pseudoarthrosis void of up to 2.5 cm was noted to be healed in subsequent imaging. In addition, clinically, the patients reported good symptomatic relief. No patient required revision surgery. Whiteclouds' outcome analysis score at the latest follow-up revealed goodto- excellent outcomes in all patients., Conclusions: ALs can be treated using the posterior-only approach with long segment fixation and posterior spinal fusion. This is a safe, simple, and quick procedure that prevents the morbidity of anterior surgery.

Andersson lesion is a destructive vertebral or disco-vertebral lesion that occurs in the late stage of the ankylosing spondylitis. According to the etiology, these lesions are usually classified into localized lesions and extensive lesions. The history of ankylosing spondylitis and characteristic imaging is the key to the diagnosis of Andersson lesion. Conservative treatment may be effective for localized lesions. However, surgical intervention is often required for the failure of conservative treatment and extensive lesions. Currently, the optimal procedure for this problem is spinal osteotomy through pseudarthrosis and debridement via posterior-only approach.

Objectives: The optimal surgical procedure for treating kyphotic deformity with Andersson lesions (ALs) in ankylosing spondylitis (AS) patients is controversial. The one-stage posterior osteotomy and bone graft fusion approach is rarely reported. The aim of the present study was to report a new surgical procedure involving one-stage posterior grade 4 osteotomy and bone graft fusion for the treatment of kyphotic deformity with ALs in AS., Patients and Methods: Eleven patients with ALs in AS were enrolled. One-stage posterior grade 4 osteotomy and bone graft fusion was performed in all patients. Frankel classification and visual analog scale (VAS) were used to evaluate neurologic deficit and the level of back pain pre- and postoperatively, respectively. Radiographic and clinical outcomes were assessed with a mean of 31.5 months follow-up., Results: Local kyphosis was corrected from 19.1° to 0.5° after surgery with a mean correction rate of 95%. One Frankel C and 5 Frankel D patients changed to Frankel D and Frankel E, respectively. VAS was reduced from 6.7 to 0.27 at final follow-up. Bone graft fusion was observed at an average of 4.3 months and solid bony fusion was achieved at final follow-up. Average operation time and blood loss were 268.6min and 1009ml, respectively. Three patients developed dural tear complications. There were no neurological or instrumentation complications reported or observed at final follow-up., Conclusion: One-stage posterior grade 4 osteotomy and bone graft fusion is an optional surgical procedure to treat ALs in AS patients. This approach results in reduced blood loss and operation time, satisfactory correction of local kyphosis, and good safety. Successful fusion and good clinical outcomes can also be achieved., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Andersson lesion is a well-known complication in ankylosing spondylitis. Recently, owing to the worry about the healing of fracture, some scholars advocated additional anterior surgery or other procedures were necessary, which increase the risk of the nerve injury. The purpose of this study is to introduce our experience and to explore the efficacy and feasibility of posterior wedge osteotomy and debridement through Andersson Lesion for surgical treatment of severe kyphosis in ankylosing spondylitis., Methods: From January 2012 to January 2014, a retrospective study of 14 Andersson lesion patients with severe kyphosis in ankylosing spondylitis treated with surgery was completed with an at least 2-year follow-up. The debridement procedure, before posterior wedge osteotomy in posterior approach, must scrape all sclerosis bone until healthy cancellous bone appears. Radiographic and clinical results and complications were assessed with an average follow-up of 24 months. The CT scan was obtained preoperatively and at the final follow-up to assess the displacement of the fracture preoperatively, the safety of screw insertion, the healing of the fracture at the final follow-up. The Bridwell interbody fusion grading system was used to assess the healing of the fracture., Results: Local kyphosis was substantially corrected from 51.7 ± 15.6 to 7.1 ± 19.5, with a mean correction of 44°. The global kyphosis (GK) changed from 60.6 ± 28.3 to 20.3 ± 10.3 (P = 0.000). The mean VAS back pain scores decreased from 6.7 ± 0.8 preoperatively to 0.75 ± 0.6 after a 2-year follow-up (P = 0.000). The ODI score improved from 60.56 ± 15.1% preoperatively to 23.46 ± 8.2% after a 2-year follow-up (P = 0.000). The CT scan showed solid fusion at the level of the AL, and no internal fixation loose. All patients achieved grade 1 fusion. No major complication occurred., Conclusions: The posterior wedge osteotomy and debridement through AL can be used to correct the severe kyphosis in ankylosing spondylitis, achieving favorable clinical outcomes, good fusion, and satisfactory deformity correction.

Objective: To investigate the clinical characteristics of ankylosing spondylitis (AS) combined Andersson lesion (AL). Methods: The clinical data of patients who were diagnosed as AS combined AL at Sun Yat-sen Memorial Hospital between January 2012 and December 2015 were reviewed retrospectively.SPSS 20.0 software was used for statistical analysis.Data of normal distribution was expressed by x ± s (standard deviation) and that of abnormal distribution by median and range. Results: Fourteen patients were enrolled. Ten were male, median age (IQR, similarly hereinafter) was 46 (29-53) years, disease duration was 120 (54-150) months, 7 has symptom increased in the beginning, 6 has nerve compression symptom, 7 has kyphosis, and 4 has spinous tenderness or percussion pain in physical examination.Eleven of AL occurred in the thoracolumbar junction.Erythrocyte sedimentation rate was 24 (15-44) mm/1 h, C-reactive protein was 10 (5-18) mg/L, and Serum amyloid A was 19 (5-31) mg/L.All the 14 patients were divided into 2 groups, aggravated group ( n =7) and none aggravated group ( n =7) according to the symptom.It was no statistic difference between them about all the above indicators. Conclusion: Imageological diagnosis should be performed to identify Andersson lesion, while ankylosing spondylitis patients combined mechanical pain based on inflammatory back pain, or mainly with nerve compression symptom, tenderness or percussion pain, or spinous, even when inflammatory markers were normal.