Postoperative tophus in the thoracic spine: a case report and literature review

Postoperative tophus in the thoracic spine: a case report and literature review | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Postoperative tophus in the thoracic spine: a case report and literature review Peng Li, Houchen Liu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7114719/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: Among all cases of spinal tophaceous gout, thoracic involvement is the least frequently reported. Here, we present a rare case of tophus formation at adjacent segments following thoracic spinal internal fixation surgery, which resulted in severe neurological symptoms. To our knowledge, no such case has been previously reported in the literature. Based on this rare presentation, we propose new insights into the preferential deposition sites of thoracic spinal tophi and provide a comprehensive review of previously reported cases. Case presentation: A 49-year-old Chinese male with an 11-year history of gout and hyperuricemia presented with a 10-month history of bilateral lower limb weakness and numbness. Anterior decompression and bone grafting with titanium plate fixation at T5–T9 were performed 16 years ago for a traumatic thoracic vertebral fracture. Imaging on admission revealed calcified space-occupying lesions located in the epidural space at T4–T5, T9–T10, and T11–T12, primarily involving segments adjacent to the surgical site. The patient underwent thoracic laminectomy with internal fixation. Postoperatively, the weakness in the lower extremities was partially improved; however, the numbness persisted. Conclusion: This case of tophus formation in segments adjacent to a previous thoracic spine surgery may be associated with segmental degeneration and increased mobility caused by postoperative biomechanical changes. axial gout thoracic spine tophus Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Gout is a chronic disease characterized by the formation of monosodium urate (MSU) crystals in the presence of elevated urate concentrations. 1 According to population-based research from Asia, Europe, and North America, the prevalence of gout has climbed gradually in the twentieth century, with prevalence rates ranging from 0.68% to 3.9% in adults. 2-7 Urate crystals in tophaceous gout typically deposit in both articular and periarticular structures, with a predilection for the metatarsophalangeal joints, ankles, knees, wrists, fingers, and shoulders. However, gouty arthritis in the axial joints is uncommon, especially in the spine. 8 All segments of the spine could be affected by axial gout. In a review of reported cases, Toprover M and Ding Y found that approximately 38.0% of patients with axial gout had lumbar involvement, 24.8% of the cervical vertebrae and 17.8% of the thoracic vertebrae were involved. 8,9 Apparently, thoracic gout is the least reported among all spinal gouts, and there were few reports on its predilection segments. In the literature reviewed by Zheng ZF, it was found that the majority of the patient with thoracic tophi occurred in T7-T10. 10 Nonetheless, the exact mechanism is still unknown. This study reported a rare case of adjacent segmental gout tophus formation after thoracic internal fixation surgery, which has never been reported in previous studies. Case description A 49-year-old male with an 11-year history of gout and hyperuricemia presented with progressive weakness and numbness in both lower extremities, which had begun 10 months prior to admission. His symptoms had gradually worsened, and he was experiencing significant difficulty walking at the time of presentation. The past medical record revealed that he suffered a traumatic thoracic vertebral fracture and subsequently underwent anterior T5–T9 bone grafting with titanium plate fixation 16 years ago. Despite his longstanding history of gout, he had not received standard or systematic treatment. Physical examination revealed a surgical scar approximately 20 cm in length extending from the left back to the anterior chest wall. An ulcerated lesion with continuous exudation of a white, viscous substance was noted over the right medial malleolus. Hypoesthesia and numbness were observed below the umbilical level (T10). Multiple tophi were present in both articular and extra-articular sites, including the metatarsophalangeal joints, ankles, knees, elbows, fingers, and auricles. Neurological examination showed decreased muscle strength in both lower limbs: grade 3/5 on the left and grade 1/5 on the right. Deep tendon reflexes were normal, and Babinski and Oppenheim signs were negative bilaterally. Laboratory test results on admission are summarized in Table 1. Digital radiography (DR) of the thoracic spine revealed titanium rods spanning T5–T9, accompanied by a screw–rod internal fixation system. Computed tomography (CT) scans in sagittal and axial views showed solid fusion of T5–T9 with mild kyphotic deformity. High-density masses were observed within the spinal canal at T4–T5, T9–T10, and T11–T12. These space-occupying lesions were predominantly located dorsally at T4–T5, on the right side at T9–T10, and on the left side at T11–T12. Magnetic resonance imaging (MRI) revealed homogeneous low signal intensity on both T1-weighted (T1WI) and T2-weighted images (T2WI) at the affected levels. (See Figures 1 and 2) Based on the clinical presentation, laboratory findings, and imaging results, a preliminary diagnosis of thoracic spinal stenosis secondary to gouty tophus was made. After evaluating the patient's overall condition, posterior decompression surgery was performed at T4–T5, T9–T10, and T11–T12 to excise the masses and relieve spinal cord compression. Intraoperatively, subperiosteal dissection of the paravertebral muscles exposed a white, chalky, cheese-like material attached to the superior articular process of T9. Following laminectomy of the affected segments, the material was found occupying more than half of the spinal canal, with indistinct boundaries between the mass, the capsule, and the dura. To minimize the risk of spinal cord injury, dural tear, and cerebrospinal fluid leakage, the capsule was preserved, and most of the intraspinal mass was carefully removed. Adequate decompression of the ventral and lateral recesses of the spinal cord was achieved, and a pedicle screw fixation system was applied to ensure spinal stability. Histopathological examination revealed amorphous basophilic material consistent with dissolved monosodium urate crystals, surrounded by a dense infiltrate of mononuclear inflammatory cells and multinucleated foreign body-type giant cells. The surrounding stroma showed fibroblast proliferation and mild neovascularization, consistent with chronic tophaceous inflammation. (See Figures 3) Based on these findings, a final diagnosis of thoracic spinal tophaceous gout was confirmed. At one-month follow-up, the patient showed partial improvement in lower limb weakness; however, numbness persisted. Discussion Kersley GD provided the first detailed and comprehensive description of spinal involvement in gout in 1950. 11 However, the first reported case of thoracic spinal gout was published by Koskoff YD in 1953. 12 To date, a total of 33 cases of thoracic spinal tophi have been reported in the literature. These cases are summarized in Table 2. According to the literature review, the male-to-female ratio among thoracic tophus cases is 26:5, slightly higher than the general epidemiological estimates of 2:1 to 4:1. 2,6,7 Patient ages ranged from 23 to 83 years, with a mean age of 48.9 years; over 75% of the cases occurred in individuals aged 30 to 65 years. Among those with available laboratory data, 17 out of 21 patients (81%) had hyperuricemia, with one patient exhibiting an extremely elevated serum uric acid level of 1290 μmol/L. (See Figures 4) Hyperuricemia and the deposition of monosodium urate crystals are pivotal in the pathogenesis of tophus formation. 41 Several risk factors can increase serum urate levels, including metabolic syndrome, chronic renal impairment, and certain medications such as diuretics and ciclosporin. Additionally, dietary factors, including purine-rich foods (e.g., red meat, seafood), alcohol (especially beer), and sugar-sweetened beverages, contribute to hyperuricemia. 42,43 Factors such as sodium ions, lower temperature, slightly alkaline pH, and specific connective tissue proteins also promote MSU crystal formation and deposition. 44 The extradural space was the most commonly involved anatomical location. 9,12-29 Other affected sites include facet joints, 25,30-32 intervertebral discs, 33 vertebral bodies, 33-37 pedicles, 13,22,32,37,38 ligamentum flavum, 30,39 and even costovertebral joint. 40 Notably, none of the previously reported cases had a history of thoracic spinal surgery, nor did they discuss the potential mechanisms contributing to the preferential deposition of tophi at certain spinal segments. Clinical manifestations of thoracic spinal gout are variable and include back pain, unilateral or bilateral lower extremity weakness or paralysis, and sensory disturbances. In rare cases, patients may present with bowel or bladder dysfunction 13,18,25,30,34,36 or abdominal wall weakness. 28 The diversity in clinical symptoms largely depends on the size, anatomical location, and extent of neural structure involvement by the tophus. Imaging modalities such as DR, CT, and MRI are commonly utilized in the evaluation of spinal gout. Among these, plain radiography is the simplest and most accessible technique; however, it lacks the sensitivity and specificity required for early or subtle lesions and is generally only informative in cases involving large tophi with associated neurological deficits. MRI findings of spinal tophi typically demonstrate homogeneous intermediate to low signal intensity on T1-weighted images. On T2-weighted images, the signal characteristics are more variable, ranging from homogeneously hyperintense to hypointense. These differences are thought to be related to the variable composition of the tophi, including calcification, mature fibrous tissue, urate crystal content, stationary protons, and hemosiderin deposits. 39 Although MRI can identify the presence of spinal tophi, the imaging features are nonspecific and may resemble other spinal lesions. CT imaging plays a critical role in the diagnosis of spinal gout. Characteristic CT findings include bone or joint erosions with well-defined sclerotic margins, which are hallmark features of axial gout. Additional manifestations may include epidural space-occupying lesions 9,14,15,17 osteolytic lesions, 35,37,38 and degenerative changes. 28 Importantly, thoracic tophi seldom present as isolated lesions and are often found in combination. The most frequently observed imaging pattern is a combination of osseous erosions and epidural involvement. 20,23,24,27,30-32,34 Compared with MRI and plain radiographs, CT offers superior spatial resolution, allowing precise visualization of calcifications and bony erosive changes associated with tophi. 53 In recent years, dual-energy computed tomography (DECT) has emerged as a particularly valuable imaging modality. DECT can detect monosodium urate crystal deposits with high sensitivity and differentiate them from soft tissue structures, thereby aiding in the differential diagnosis. Furthermore, DECT facilitates accurate surgical planning by clearly delineating the extent and location of crystal deposition. Our literature review confirmed that T7–T11 is the most frequent region of thoracic tophi deposition, consistent with the findings of Zheng ZF, who suggested that the vulnerability of this segment may be associated with inflammation and mechanical stress due to spinal motion. 10 However, the exact pathophysiological mechanism remains unclear. In the present case, the patient developed thoracic spinal tophi following anterior spinal fusion and internal fixation (T5–T9), with deposition mainly in the adjacent segments. This observation provides valuable insight into potential mechanisms underlying the preferential localization of tophi. Spinal fusion and internal fixation are standard treatments for various spinal disorders but are known to predispose patients to adjacent segment disease (ASD), which may manifest as degeneration or instability in segments adjacent to the fused spine. 45,46 Contributing factors include postoperative biomechanical alterations and redistribution of range of motion, resulting in increased stress on neighboring segments. Additional risk factors for ASD include pre-existing disc degeneration, 47 long fusion segment, 48 rigid instrumentation, 49 spinal anatomical anomalies 50 and inadequate restoration of spinal alignment, vertebral height, or disc space. 51,52 In this patient, imaging revealed that tophi were predominantly deposited at levels adjacent to the prior fusion site (T5–T9), suggesting that biomechanical changes—particularly increased mobility and subsequent degeneration—may have created a local environment conducive to urate crystal deposition. In cases of spinal tophus with neurological compromise, surgical decompression remains the most effective treatment. However, delayed intervention, large tophi, and chronic spinal cord compression may lead to suboptimal postoperative recovery. Early surgical treatment is therefore recommended to improve neurological outcomes. Additionally, in patients with a history of spinal fusion and internal fixation, serum uric acid levels should be tightly controlled, and regular imaging surveillance (CT or MRI) is advised to detect early adjacent segmental urate deposition. Conclusion The case of tophus in adjacent segments after thoracic spine surgery has not been reported before, which may be related to the degeneration or increased range of motion due to biomechanical changes in the adjacent segments. It is significant for exploring the predilection sites of tophi. In addition, for gout patients who have undergone spinal fusion or fixation surgery in the past, clinicians should pay more attention to the possible later occurrence of adjacent segmental tophi deposition. Abbreviations MSU: Hyperuricemia and monosodium urate; DR: Digital radiography; CT: Computed tomography; MRI: Magnetic resonance imaging; T1WI: T1-weighted images; T2WI: T2-weighted images; DECT: Dual-energy computed tomography; ASD: adjacent segment disease Declarations Ethics approval and consent to participate This study was approved by the ethics committee of the Affiliated Hospital of Qingdao University. Written informed consent was obtained from the patient. Consent for publication Written informed consent were obtained from the patient for publication of this case report. Availability of data and materials The data that support the findings of this study are available on request from the corresponding author. Clinical trial number Not applicable. Competing interests The authors declare that they have no competing interests. Funding No funding was received for this study. Authors’ contributions HCL and PL are responsible for patient clinical diagnosis and surgery; PL collected patient clinical data and drafted the manuscript. HCL reviewed the literature. Acknowledgements Thanks to all staff of the Orthopedic Medical Center of the Affiliated Hospital of Qingdao University for their support and selfless dedication. References Dalbeth N, Merriman TR, Stamp LK. Gout. Lancet (London, England). 2016;388(10055):2039-2052. Kuo CF, Grainge MJ, Mallen C, Zhang W, Doherty M. Rising burden of gout in the UK but continuing suboptimal management: a nationwide population study. Annals of the rheumatic diseases. 2015;74(4):661-667. Dehlin M, Drivelegka P, Sigurdardottir V, Svärd A, Jacobsson LT. Incidence and prevalence of gout in Western Sweden. Arthritis research & therapy. 2016;18:164. Kim JW, Kwak SG, Lee H, Kim SK, Choe JY, Park SH. 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European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2001;10(4):314-319. Lumezanu E, Konatalapalli R, Weinstein A. Axial (spinal) gout. Current rheumatology reports. 2012;14(2):161-164. Tables Table 1 and 2 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files table1.docx table2.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7114719","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":495003174,"identity":"2a7863b8-46f3-401d-b38e-d64825305952","order_by":0,"name":"Peng Li","email":"","orcid":"","institution":"The Affiliated Hospital of Qingdao University","correspondingAuthor":false,"prefix":"","firstName":"Peng","middleName":"","lastName":"Li","suffix":""},{"id":495003175,"identity":"6cbcd52c-5d1a-4b75-aa3a-b63eaca69405","order_by":1,"name":"Houchen Liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIiWNgGAWjYBACPmYGNhCdwMDA2PjwQwWQyQ5kNuDRwobQwtxsLHGGgYGHmZAWBrgW9jYJ3jZitLDzmD342GaXxy/d2CAhOc8mcT8z88GHMxjs5HRx6GNj5jE3nNmWXCw552CDQeG2tMQeZrZkww0MycZmB3BqMZPmbTuQuOFGYkOC5LbDQC08ZpIPGA4kbiOkZT9QywHeOaRo2SCR2NjA2wDVsgGvFrYyyRnnkhNn3EhsZpY4lmbccxjolxkGuP3Cz394m8SHMrvE/hnpz39+qLGRbW9vPviwp8JODpcWXMCANOWjYBSMglEwClABACfPVsdv7seqAAAAAElFTkSuQmCC","orcid":"","institution":"Siegfried Weller Institute, BG-Klinik Tübingen, Eberhard Karls University","correspondingAuthor":true,"prefix":"","firstName":"Houchen","middleName":"","lastName":"Liu","suffix":""}],"badges":[],"createdAt":"2025-07-13 17:23:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7114719/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7114719/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88348121,"identity":"55268dd9-1d51-4633-9276-b0d4c8287d9c","added_by":"auto","created_at":"2025-08-05 13:58:46","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":209753,"visible":true,"origin":"","legend":"\u003cp\u003e(a) DR lateral view of the thoracic spine; (b) DR anteroposterior view of the thoracic spine; (c) T1-weighted image; (d) T2-weighted image; (e) Dual-energy CT imaging;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNotes: \u003c/strong\u003eThe red arrow indicates the location of the tophi\u003c/p\u003e","description":"","filename":"figure1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7114719/v1/982109461b44859cd2e64f8f.jpeg"},{"id":88349589,"identity":"a043331d-8f29-419b-87eb-fc606290729c","added_by":"auto","created_at":"2025-08-05 14:06:46","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":132901,"visible":true,"origin":"","legend":"\u003cp\u003e(f) CT bone window sagittal imaging; (g) CT soft tissue window sagittal imaging; (h) The lesion at T4-T5 level; (i) The lesion at T9-T10 level; (j) The lesion at T11-T12 level\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNotes: \u003c/strong\u003eThe red arrow indicates the location of the tophi\u003c/p\u003e","description":"","filename":"figure2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7114719/v1/f566ea1e7c0e2a4a226fd818.jpeg"},{"id":88348131,"identity":"3f1c3930-f0b9-4b7f-93b2-f1ae599e66aa","added_by":"auto","created_at":"2025-08-05 13:58:46","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":245847,"visible":true,"origin":"","legend":"\u003cp\u003ePathological pictures of patients with tophi after HE staining\u003c/p\u003e","description":"","filename":"figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7114719/v1/f853974814e366d97f6eb68b.jpg"},{"id":88350602,"identity":"937aa30d-51c9-4376-9902-7bf5e59583d7","added_by":"auto","created_at":"2025-08-05 14:14:46","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":122872,"visible":true,"origin":"","legend":"\u003cp\u003e(k) Uric acid distribution by age and gender (l) Distribution of the involved segments\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNotes: \u003c/strong\u003eTwo grey lines indicate normal uric acid levels\u003c/p\u003e","description":"","filename":"figure4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7114719/v1/46d6652c2e80eeb04ddb5f8b.jpeg"},{"id":108122328,"identity":"74eb2433-6a84-46a9-806f-f1d223333b4a","added_by":"auto","created_at":"2026-04-29 14:41:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":927861,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7114719/v1/62d25820-815b-4d21-b030-ff1b7de34afc.pdf"},{"id":88348125,"identity":"7699aaf4-d55a-432e-83a3-d131fecfdb67","added_by":"auto","created_at":"2025-08-05 13:58:46","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":14541,"visible":true,"origin":"","legend":"","description":"","filename":"table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7114719/v1/8f385453544116b969fb99b2.docx"},{"id":88348120,"identity":"39415b99-884a-4e78-9026-808c3b7cf8dc","added_by":"auto","created_at":"2025-08-05 13:58:46","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":48979,"visible":true,"origin":"","legend":"","description":"","filename":"table2.docx","url":"https://assets-eu.researchsquare.com/files/rs-7114719/v1/f8deef3d89fd123c868bd5d8.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Postoperative tophus in the thoracic spine: a case report and literature review","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGout is a chronic disease characterized by the formation of monosodium urate (MSU) crystals in the presence of elevated urate concentrations.\u003csup\u003e1\u003c/sup\u003e According to population-based research from Asia, Europe, and North America, the prevalence of\u0026nbsp;gout\u0026nbsp;has climbed gradually in the twentieth century, with prevalence rates ranging from 0.68% to 3.9% in adults.\u003csup\u003e2-7\u003c/sup\u003e Urate crystals in tophaceous gout typically deposit in both articular and periarticular structures, with a predilection for the metatarsophalangeal joints, ankles, knees, wrists, fingers, and shoulders.\u0026nbsp;However, gouty arthritis in the axial joints is uncommon, especially in the spine.\u003csup\u003e8\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eAll segments of the spine could be affected by axial gout. In a review of reported cases, Toprover M and Ding Y found that approximately 38.0% of patients with axial gout had lumbar involvement, 24.8% of the cervical vertebrae and 17.8% of the thoracic vertebrae were involved.\u003csup\u003e8,9\u003c/sup\u003e Apparently, thoracic gout is the least reported among all spinal gouts, and there were few reports on its predilection segments. In the literature reviewed by Zheng ZF, it was found that the majority of the patient with thoracic tophi occurred in T7-T10.\u003csup\u003e10\u003c/sup\u003e Nonetheless, the exact mechanism is still unknown.\u003c/p\u003e\n\u003cp\u003eThis study reported a rare case of adjacent segmental gout tophus formation after thoracic internal fixation surgery, which has never been reported in previous studies.\u003c/p\u003e"},{"header":"Case description","content":"\u003cp\u003eA 49-year-old male with an 11-year history of gout and hyperuricemia presented with progressive weakness and numbness in both lower extremities, which had begun 10 months prior to admission. His symptoms had gradually worsened, and he was experiencing significant difficulty walking at the time of presentation. The past medical record revealed that he suffered a traumatic thoracic vertebral fracture and subsequently underwent anterior T5\u0026ndash;T9 bone grafting with titanium plate fixation 16 years ago. Despite his longstanding history of gout, he had not received standard or systematic treatment.\u003c/p\u003e\n\u003cp\u003ePhysical examination revealed a surgical scar approximately 20 cm in length extending from the left back to the anterior chest wall. An ulcerated lesion with continuous exudation of a white, viscous substance was noted over the right medial malleolus. Hypoesthesia and numbness were observed below the umbilical level (T10). Multiple tophi were present in both articular and extra-articular sites, including the metatarsophalangeal joints, ankles, knees, elbows, fingers, and auricles. Neurological examination showed decreased muscle strength in both lower limbs: grade 3/5 on the left and grade 1/5 on the right. Deep tendon reflexes were normal, and Babinski and Oppenheim signs were negative bilaterally. Laboratory test results on admission are summarized in Table 1.\u003c/p\u003e\n\u003cp\u003eDigital radiography (DR) of the thoracic spine revealed titanium rods spanning T5\u0026ndash;T9, accompanied by a screw\u0026ndash;rod internal fixation system. Computed tomography (CT) scans in sagittal and axial views showed solid fusion of T5\u0026ndash;T9 with mild kyphotic deformity. High-density masses were observed within the spinal canal at T4\u0026ndash;T5, T9\u0026ndash;T10, and T11\u0026ndash;T12. These space-occupying lesions were predominantly located dorsally at T4\u0026ndash;T5, on the right side at T9\u0026ndash;T10, and on the left side at T11\u0026ndash;T12. Magnetic resonance imaging (MRI) revealed homogeneous low signal intensity on both T1-weighted (T1WI) and T2-weighted images (T2WI) at the affected levels.\u0026nbsp;(See Figures 1 and 2)\u003c/p\u003e\n\u003cp\u003eBased on the clinical presentation, laboratory findings, and imaging results, a preliminary diagnosis of thoracic spinal stenosis secondary to gouty tophus was made. After evaluating the patient\u0026apos;s overall condition, posterior decompression surgery was performed at T4\u0026ndash;T5, T9\u0026ndash;T10, and T11\u0026ndash;T12 to excise the masses and relieve spinal cord compression.\u003c/p\u003e\n\u003cp\u003eIntraoperatively, subperiosteal dissection of the paravertebral muscles exposed a white, chalky, cheese-like material attached to the superior articular process of T9. Following laminectomy of the affected segments, the material was found occupying more than half of the spinal canal, with indistinct boundaries between the mass, the capsule, and the dura. To minimize the risk of spinal cord injury, dural tear, and cerebrospinal fluid leakage, the capsule was preserved, and most of the intraspinal mass was carefully removed. Adequate decompression of the ventral and lateral recesses of the spinal cord was achieved, and a pedicle screw fixation system was applied to ensure spinal stability. Histopathological examination revealed amorphous basophilic material consistent with dissolved monosodium urate crystals, surrounded by a dense infiltrate of mononuclear inflammatory cells and multinucleated foreign body-type giant cells. The surrounding stroma showed fibroblast proliferation and mild neovascularization, consistent with chronic tophaceous inflammation.\u0026nbsp;(See Figures 3)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Based on these findings, a final diagnosis of thoracic spinal tophaceous gout was confirmed. At one-month follow-up, the patient showed partial improvement in lower limb weakness; however, numbness persisted.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eKersley GD provided the first detailed and comprehensive description of spinal involvement in gout in 1950.\u003csup\u003e11\u003c/sup\u003e However, the first reported case of thoracic spinal gout was published by Koskoff YD in 1953.\u003csup\u003e12\u003c/sup\u003e To date, a total of 33 cases of thoracic spinal tophi have been reported in the literature. These cases are summarized in Table 2.\u003c/p\u003e\n\u003cp\u003eAccording to the literature review, the male-to-female ratio among thoracic tophus cases is 26:5, slightly higher than the general epidemiological estimates of 2:1 to 4:1.\u003csup\u003e2,6,7\u003c/sup\u003e Patient ages ranged from 23 to 83 years, with a mean age of 48.9 years; over 75% of the cases occurred in individuals aged 30 to 65 years. Among those with available laboratory data, 17 out of 21 patients (81%) had hyperuricemia, with one patient exhibiting an extremely elevated serum uric acid level of 1290 \u0026mu;mol/L.\u0026nbsp;(See Figures\u0026nbsp;4)\u003c/p\u003e\n\u003cp\u003eHyperuricemia and the deposition of monosodium urate crystals are pivotal in the pathogenesis of tophus formation.\u003csup\u003e41\u003c/sup\u003e Several risk factors can increase serum urate levels, including metabolic syndrome, chronic renal impairment, and certain medications such as diuretics and ciclosporin. Additionally, dietary factors, including purine-rich foods (e.g., red meat, seafood), alcohol (especially beer), and sugar-sweetened beverages, contribute to hyperuricemia.\u003csup\u003e42,43\u003c/sup\u003e Factors such as sodium ions, lower temperature, slightly alkaline pH, and specific connective tissue proteins also promote MSU crystal formation and deposition.\u003csup\u003e44\u003c/sup\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe extradural space was the most commonly involved anatomical location.\u003csup\u003e9,12-29\u003c/sup\u003e Other affected sites include facet joints,\u003csup\u003e25,30-32\u003c/sup\u003e intervertebral discs,\u003csup\u003e33\u003c/sup\u003e vertebral bodies,\u003csup\u003e33-37\u003c/sup\u003e pedicles,\u003csup\u003e13,22,32,37,38\u003c/sup\u003e ligamentum flavum,\u003csup\u003e30,39\u003c/sup\u003e and even costovertebral joint.\u003csup\u003e40\u003c/sup\u003e Notably, none of the previously reported cases had a history of thoracic spinal surgery, nor did they discuss the potential mechanisms contributing to the preferential deposition of tophi at certain spinal segments.\u003c/p\u003e\n\u003cp\u003eClinical manifestations of thoracic spinal gout are variable and include back pain, unilateral or bilateral lower extremity weakness or paralysis, and sensory disturbances. In rare cases, patients may present with bowel or bladder dysfunction\u003csup\u003e13,18,25,30,34,36\u003c/sup\u003e or abdominal wall weakness.\u003csup\u003e28\u003c/sup\u003e The diversity in clinical symptoms largely depends on the size, anatomical location, and extent of neural structure involvement by the tophus.\u003c/p\u003e\n\u003cp\u003eImaging modalities such as DR, CT, and MRI are commonly utilized in the evaluation of spinal gout. Among these, plain radiography is the simplest and most accessible technique; however, it lacks the sensitivity and specificity required for early or subtle lesions and is generally only informative in cases involving large tophi with associated neurological deficits. MRI findings of spinal tophi typically demonstrate homogeneous intermediate to low signal intensity on T1-weighted images. On T2-weighted images, the signal characteristics are more variable, ranging from homogeneously hyperintense to hypointense. These differences are thought to be related to the variable composition of the tophi, including calcification, mature fibrous tissue, urate crystal content, stationary protons, and hemosiderin deposits.\u003csup\u003e39\u003c/sup\u003e Although MRI can identify the presence of spinal tophi, the imaging features are nonspecific and may resemble other spinal lesions. CT imaging plays a critical role in the diagnosis of spinal gout. Characteristic CT findings include bone or joint erosions with well-defined sclerotic margins, which are hallmark features of axial gout. Additional manifestations may include epidural space-occupying lesions\u003csup\u003e9,14,15,17\u003c/sup\u003e osteolytic lesions,\u003csup\u003e35,37,38\u003c/sup\u003e and degenerative changes.\u003csup\u003e28\u003c/sup\u003e Importantly, thoracic tophi seldom present as isolated lesions and are often found in combination. The most frequently observed imaging pattern is a combination of osseous erosions and epidural involvement.\u003csup\u003e20,23,24,27,30-32,34\u003c/sup\u003e Compared with MRI and plain radiographs, CT offers superior spatial resolution, allowing precise visualization of calcifications and bony erosive changes associated with tophi.\u003csup\u003e53\u003c/sup\u003e In recent years, dual-energy computed tomography (DECT) has emerged as a particularly valuable imaging modality. DECT can detect monosodium urate crystal deposits with high sensitivity and differentiate them from soft tissue structures, thereby aiding in the differential diagnosis. Furthermore, DECT facilitates accurate surgical planning by clearly delineating the extent and location of crystal deposition.\u003c/p\u003e\n\u003cp\u003eOur literature review confirmed that T7\u0026ndash;T11 is the most frequent region of thoracic tophi deposition, consistent with the findings of Zheng ZF, who suggested that the vulnerability of this segment may be associated with inflammation and mechanical stress due to spinal motion.\u003csup\u003e10\u003c/sup\u003e However, the exact pathophysiological mechanism remains unclear. In the present case, the patient developed thoracic spinal tophi following anterior spinal fusion and internal fixation (T5\u0026ndash;T9), with deposition mainly in the adjacent segments. This observation provides valuable insight into potential mechanisms underlying the preferential localization of tophi.\u003c/p\u003e\n\u003cp\u003eSpinal fusion and internal fixation are standard treatments for various spinal disorders but are known to predispose patients to adjacent segment disease (ASD), which may manifest as degeneration or instability in segments adjacent to the fused spine.\u003csup\u003e45,46\u003c/sup\u003e Contributing factors include postoperative biomechanical alterations and redistribution of range of motion, resulting in increased stress on neighboring segments. Additional risk factors for ASD include pre-existing disc degeneration,\u003csup\u003e47\u003c/sup\u003e long fusion segment,\u003csup\u003e48\u003c/sup\u003e rigid instrumentation,\u003csup\u003e49\u003c/sup\u003e spinal anatomical anomalies\u003csup\u003e50\u003c/sup\u003e and inadequate restoration of spinal alignment, vertebral height, or disc space.\u003csup\u003e51,52\u003c/sup\u003e In this patient, imaging revealed that tophi were predominantly deposited at levels adjacent to the prior fusion site (T5\u0026ndash;T9), suggesting that biomechanical changes\u0026mdash;particularly increased mobility and subsequent degeneration\u0026mdash;may have created a local environment conducive to urate crystal deposition.\u003c/p\u003e\n\u003cp\u003eIn cases of spinal tophus with neurological compromise, surgical decompression remains the most effective treatment. However, delayed intervention, large tophi, and chronic spinal cord compression may lead to suboptimal postoperative recovery. Early surgical treatment is therefore recommended to improve neurological outcomes. Additionally, in patients with a history of spinal fusion and internal fixation, serum uric acid levels should be tightly controlled, and regular imaging surveillance (CT or MRI) is advised to detect early adjacent segmental urate deposition.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe case of tophus in adjacent segments after thoracic spine surgery has not been reported before, which may be related to the degeneration or increased range of motion due to biomechanical changes in the adjacent segments. It is significant for exploring the predilection sites of tophi. In addition, for gout patients who have undergone spinal fusion or fixation surgery in the past, clinicians should pay more attention to the possible later occurrence of adjacent segmental tophi deposition.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eMSU: Hyperuricemia and monosodium urate; DR: Digital radiography; CT: Computed tomography; MRI: Magnetic resonance imaging; T1WI: T1-weighted images; T2WI: T2-weighted images; DECT: Dual-energy computed tomography; ASD: adjacent segment disease\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the ethics committee of the Affiliated Hospital of Qingdao University. Written informed consent was obtained from the patient.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent were obtained from the patient for publication of this case report.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available on request from the corresponding author.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received for this study.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHCL and PL are responsible for patient clinical diagnosis and surgery; PL collected patient clinical data and drafted the manuscript. HCL reviewed the literature.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThanks to all staff of the Orthopedic Medical Center of the Affiliated Hospital of Qingdao University for their support and selfless dedication.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDalbeth N, Merriman TR, Stamp LK. Gout. \u003cem\u003eLancet (London, England). \u003c/em\u003e2016;388(10055):2039-2052.\u003c/li\u003e\n\u003cli\u003eKuo CF, Grainge MJ, Mallen C, Zhang W, Doherty M. Rising burden of gout in the UK but continuing suboptimal management: a nationwide population study. \u003cem\u003eAnnals of the rheumatic diseases. \u003c/em\u003e2015;74(4):661-667.\u003c/li\u003e\n\u003cli\u003eDehlin M, Drivelegka P, Sigurdardottir V, Sv\u0026auml;rd A, Jacobsson LT. Incidence and prevalence of gout in Western Sweden. \u003cem\u003eArthritis research \u0026amp; therapy. \u003c/em\u003e2016;18:164.\u003c/li\u003e\n\u003cli\u003eKim JW, Kwak SG, Lee H, Kim SK, Choe JY, Park SH. Prevalence and incidence of gout in Korea: data from the national health claims database 2007-2015. \u003cem\u003eRheumatology international. \u003c/em\u003e2017;37(9):1499-1506.\u003c/li\u003e\n\u003cli\u003eRai SK, Avi\u0026ntilde;a-Zubieta JA, McCormick N, et al. The rising prevalence and incidence of gout in British Columbia, Canada: Population-based trends from 2000 to 2012. \u003cem\u003eSeminars in arthritis and rheumatism. \u003c/em\u003e2017;46(4):451-456.\u003c/li\u003e\n\u003cli\u003eChen-Xu M, Yokose C, Rai SK, Pillinger MH, Choi HK. 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Axial (spinal) gout. \u003cem\u003eCurrent rheumatology reports. \u003c/em\u003e2012;14(2):161-164.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 and 2 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"axial gout, thoracic spine, tophus","lastPublishedDoi":"10.21203/rs.3.rs-7114719/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7114719/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003eAmong all cases of spinal tophaceous gout, thoracic involvement is the least frequently reported. Here, we present a rare case of tophus formation at adjacent segments following thoracic spinal internal fixation surgery, which resulted in severe neurological symptoms. To our knowledge, no such case has been previously reported in the literature. Based on this rare presentation, we propose new insights into the preferential deposition sites of thoracic spinal tophi and provide a comprehensive review of previously reported cases.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation: \u003c/strong\u003eA 49-year-old Chinese male with an 11-year history of gout and hyperuricemia presented with a 10-month history of bilateral lower limb weakness and numbness. Anterior decompression and bone grafting with titanium plate fixation at T5–T9 were performed 16 years ago for a traumatic thoracic vertebral fracture. Imaging on admission revealed calcified space-occupying lesions located in the epidural space at T4–T5, T9–T10, and T11–T12, primarily involving segments adjacent to the surgical site. The patient underwent thoracic laminectomy with internal fixation. Postoperatively, the weakness in the lower extremities was partially improved; however, the numbness persisted.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eThis case of tophus formation in segments adjacent to a previous thoracic spine surgery may be associated with segmental degeneration and increased mobility caused by postoperative biomechanical changes.\u003c/p\u003e","manuscriptTitle":"Postoperative tophus in the thoracic spine: a case report and literature review","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-05 13:58:41","doi":"10.21203/rs.3.rs-7114719/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c6be6b9b-814a-49c8-810d-5332e8f103b0","owner":[],"postedDate":"August 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-29T14:41:01+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-05 13:58:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7114719","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7114719","identity":"rs-7114719","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}