Four-Level Pedicle Subtraction Osteotomy for Severe Rigid Thoracic Hyperkyphosis: A Technical Case Report

Four-Level Pedicle Subtraction Osteotomy for Severe Rigid Thoracic Hyperkyphosis: A Technical Case Report | 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 Research Article Four-Level Pedicle Subtraction Osteotomy for Severe Rigid Thoracic Hyperkyphosis: A Technical Case Report Cécile Roscop, Anouar Bourghli, Daniel Larrieu, Louis Boissière, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8172930/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Jan, 2026 Read the published version in European Spine Journal → Version 1 posted 8 You are reading this latest preprint version Abstract Study Design: Technical case report Introduction: Severe thoracic hyperkyphosis caused by multiple osteoporotic fractures can lead to significant disability. When deformities are rigid, surgical correction may be required. This report describes a rare case of four-level pedicle subtraction osteotomy (PSO) to address a fixed deformity, with focus on technique, outcomes, and complications. Case Presentation: A 65-year-old female with Scheuermann’s disease developed progressive thoracic hyperkyphosis due to osteoporotic vertebral fractures. Radiographs showed a rigid kyphosis of 130.3°. The patient underwent a two-stage surgery: cement-augmented instrumentation (T2–L3), followed by contiguous PSOs from T6 to T9. Neurophysiological monitoring was used throughout. Results: Kyphosis was corrected from 130.3° to 48°. Postoperatively, the patient developed progressive lower limb weakness due to spinal cord kinking. Revision surgery allowed neurological recovery. At two years, radiological parameters remained stable, and the patient reported reduced pain, improved mobility, and restored quality of life. Conclusion: Four-level PSO can be an effective treatment for severe rigid thoracic hyperkyphosis in osteoporotic patients. Although technically demanding and associated with potential complications, careful planning and staged correction can result in successful outcomes. LEVEL OF EVIDENCE IV (Case Report) Kyphosis Osteotomy Scheuermann Disease Spinal Fusion Spinal Curvatures Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 INTRODUCTION Severe thoracic hyperkyphosis is a disabling condition that can result from congenital conditions, however it may be the consequence of multiple osteoporotic fractures of the vertebrae. This latter condition can lead to significant pain, disability, and decreased quality of life [ 1 , 2 ]. While conservative measures such as bracing and medical treatment may be effective in some cases [ 3 ], more severe and rigid deformities may require surgical intervention. The multilevel pedicle subtraction osteotomy (PSO) is a complex surgical technique used to correct severe adult spinal deformities such as thoracic hyperkyphosis. This procedure involves vertebral body osteotomy at one or more segments, followed by spinal shortening and fusion [ 4 – 8 ]. To our knowledge, this is the first study which presents a four-level PSO procedure for the treatment of a patient with severe and rigid thoracic hyperkyphosis resulting from multiple osteoporotic fractures. This report aims to describe the technical aspects of the surgery, outcomes, and potential complications associated with this procedure. CASE REPORT A 65-year-old female patient known for Scheuermann's disease since childhood was referred to our spine unit for the treatment of an extremely severe thoracic hyperkyphosis. Her thoracic kyphosis progressively worsened due to osteoporotic vertebral fractures at the apical thoracic area (lumbar T-score − 3.9) despite regular follow-up in the rheumatology department. The patient suffered a decrease in her quality of life as well as respiratory discomfort. Standing was only possible for a few minutes, and the seated position made it impossible to maintain horizontal gaze. She had an ODI disability score of 65. Due to the severity of osteoporosis, treatment with alendronate was initiated 6 months prior to surgery. Clinical examination revealed severe upper thoracic kyphotic deformity associated with low back pain, due to facet joint syndrome because of compensatory hyperlordosis. She required a walker frame for ambulation. Neurological evaluation shows normal motor and sensory function, no bowel or bladder dysfunction, reflexes were normal. Preoperative full-spine X-ray showed a pelvic incidence of 43,1°, a pelvic tilt of 28,0°, a thoracic kyphosis T4T12 of 130,3°, a lumbar lordosis of 45,7°, a SVA at -27 mm and a global tilt angle of 31,5°(Fig. 1 ) [ 9 ], showing a severe sagittal malalignment [ 10 ]. Supine traction x-rays showed a non-flexible rigid kyphosis. CT scan and MRI confirmed the deformity with the presence of multiple healed osteoporotic fractures (Fig. 2 ). Given the severity of the deformity, its progressive worsening, as well as the major impact on the quality of life despite conservative treatments, the patient underwent corrective surgery with a single-posterior approach with vertebral Pedicle subtraction osteotomy at 4 levels from T6 to T9 (Grade 4B and 4C according to the classification described by Bourghli[ 11 ]) with instrumentation from T2 to L3. Such procedure is complex and challenging for two reasons: the severity of the thoracic kyphosis measured at 130.3°, and the presence of severe osteoporosis with high-risk of mechanical failure of the instrumentation. Thorough assessment and planning, it was decided to perform the surgery in two stages: a first-stage for the insertion of the instrumentation with cement-augmented screws, and a second-stage for the osteotomies and deformity correction. Surgical technique Under general anesthesia, the patient was positioned in a prone position (Fig. 3 ). The head was fixed in a Mayfield clamp to facilitate installation and allow external reduction maneuver. A computer-assisted navigation system (O-arm Surgical Imaging with StealthStation, Medtronic, Minneapolis, MN) and neurophysiological monitoring with somatosensory-evoked potentials and transcranial motor-evoked potentials were used in both surgical stages. The objective of the first-stage was to perform the approach and insert implants. Through a posterior midline incision, a subperiosteal dissection was carried out, exposing the posterior spinal elements. After fluoroscopic confirmation of the correct level, pedicle screws were inserted from T2 to T5 proximally with the assistance of the navigation and T10 to L3 distally by using the free-hand technique. All pedicle screws were cemented to avoid implant failure. No release maneuvers were performed at this stage. The surgery lasted 3h hours. Estimated blood loss was approximately 300 mL. Neurological monitoring showed no change. The second-stage was performed one week later. In order to obtain a satisfactory correction, it was decided to perform 4 level contiguous PSOs at the apex of the thoracic kyphosis including T6, T7, T8 and T9. A revision of the previous incision was made. The different steps of the PSO technique are described in the following paragraph. It was first performed at (T6) and then repeated at the other levels (T7, T8 and T9). Preparatory holes were made in the pedicles at each level of the osteotomy PSO level, as guidance for the osteotomy. Costotransverse joint and rib were exposed bilaterally. The rib was cut two centimeters laterally from the costotransverse joint. The neurovascular bundle was preserved and particular attention was paid to not violate the parietal pleura. After transverse processes resection, the rib heads were disarticulated allowing exposure of the lateral part of the vertebral body. A cobb elevator was placed on the lateral wall bilaterally to retract the lateral soft tissues. A wide laminectomy was performed, as well as bilateral foraminotomies cephalad and caudal to the pedicle. Pedicles and the vertebral body were progressively removed using rongeurs, curettes, and high-speed drilling. Three osteotomes were used to perform the transpedicular wedge osteotomy. Proximal disc was resected with a curette in order to obtain bone on bone contact. The posterior wall of the vertebral body was anteriorly impacted by a dedicated osteotome and impactor. Proximal level laminotomy was performed to mechanically allow the closure of the osteotomy, thus avoiding and decreasing dural kinking risks (Fig. 4 ). After performing the osteotomies at each level, pre-bent rods were gently and progressively persuaded into the screws. A domino system was used for the reduction which involved simultaneous internal and external maneuvers. the external maneuver mobilized the patient's head in extension using the Mayfield clamp, and the internal maneuver applied cantilevering on the proximal and distal rods with compression on the domino achieving satisfactory closure with bone on bone contact [ 12 ] ((Fig. 5 ). To achieve fusion, local autologous morselized graft mixed with vancomycin powder was placed after decortication of the spinal posterior elements. Neurophysiological monitoring with somatosensory-evoked potentials and transcranial motor-evoked potentials did not show any modifications The operating time was 3h15min, blood loss was 1650 mL. The patient spent her first night in intensive care unit. Immediate postoperative CT scan was done and showed a thoracic kyphosis T4T12 of 15.1, with a reduction of 115.2°. Postoperative course After surgery, the patient's neurological condition, wound status, and pulmonary function were closely monitored. She started to present motor weakness of her right lower limb, which appeared progressively over several hours and became significant at 72 hours. A postoperative MRI was able to highlight an unexpectedly tortuous spinal cord at the osteotomy levels, Explaining poor neurological tolerance after spinal shortening (Fig. 5 ). An immediate revision surgery was performed in order to decrease the reduction and check spinal cord release. The neurological improvement was immediately visible upon awakening. The patient was discharged from the hospital after 2 weeks following spine surgery with the use of a walking frame for ambulation. The patient reported an increase in quality of life following the surgery (ODI 39), with decreased pain and improved mobility. Radiological parameters also showed significant improvement, with a reduction in thoracic hyperkyphosis of 82.5° (preoperative TK 130.3° and post operative TK 47.8°) and improved spinal alignment: SVA 5mm, GT 24,0°, PT 21,2°, LL L1S1 39,8° (Fig. 6 ), which meant proportioned sagittal balance. The patient demonstrated excellent progress following the surgery, with no major complications observed during the follow-up period and independent walking after 6 months. 2 years CT scan confirmed complete fusion at the osteotomy sites with no signs of implant failure. Radiological parameters remained unchanged on the 2 years full spine X-rays: KT T4T12 48,0°, GT 25,1°, PT 21,6°, L1S1 41,4°. DISCUSSION Performing multiple PSOs in a single patient is a complex surgical technique used to correct severe spinal deformities such as thoracic hyperkyphosis [ 13 ]. Our case report describes a satisfactory outcome of a four-level PSO procedure for the treatment of a patient with severe and rigid thoracic hyperkyphosis due to multiple osteoporotic fractures. Such procedure is typically reserved for patients with severe and rigid spinal deformities that cannot be corrected with more conservative measures such as bracing or medical treatment. It is based on careful patient selection, thorough preoperative planning, and should be performed only within a setting used to complex spinal deformity management. Several authors described different algorithms to determine the proper technique of correction depending on thoracic kyphosis value, rigidity of the deformity and the sagittal imbalance [ 5 , 8 ]. Three-column osteotomies such as vertebral column resection (VCR) or PSO are powerful methods of focal rigid thoracic deformity correction [ 8 ] and has been suggested as correcting procedures when the deformity is not amenable to other osteotomy techniques such as Ponte or posterior column osteotomies [ 5 ][ 7 , 14 , 15 ][ 16 ]. VCR is a highly effective technique for correcting severe spinal deformities, offering significant correction and restoration of spinal alignment. However, due to its inherent high risks and potential complications, this surgical procedure has been primarily advised for pediatric cases where the potential benefits outweigh the risks[ 5 , 17 ]. In elderly patients or those with compromised bone quality, PSO is often favored as a less aggressive alternative. Multilevel VCR often requires a structural cage or extent bone graft for anterior support to prevent risks of spinal cord kinking and malunion. Whereas PSO can produce substantial correction at a single level, with high union rate due to the bone on bone contact at the osteotomy closure site, without the need of an anterior support (Fig. 7 ). Multilevel noncontiguous PSO has established itself as a well-recognized surgical tool for correcting adult spinal deformities, such as Scheuermann disease or ankylosing spondylitis, with the aim of achieving improved good distribution of sagittal balance[ 18 ][ 19 ]. Additionally, multiple-level PSO helps distribute the corrective forces across a larger segment of the spine. This distributed correction reduces the risk of placing excessive stress on a single osteotomy site, minimizing the chances of hardware failure and nonunion. Literature is scarce about multiple level PSO, mainly describing noncontiguous PSO in adult spinal deformities [ 18 , 20 , 21 ]. Lau and al. presented two-level noncontiguous PSO in upper thoracic spine and midthoracic spine which provide 88° and 68° of TK correction respectively[ 18 ]. To our knowledge, no previous study described a four-level contiguous PSO in the elderly patient with osteoporosis comorbidity. Our patient’s postoperative imaging showed a significant correction of the spinal deformity, as well as improved pulmonary function. However, the procedure was not without risks, as demonstrated by the onset of progressive postoperative lower limb weakness. Authors in the literature found a 30% rate of early complications, including 8% with neurological deficits requiring further decompression [ 22 ][ 5 , 8 ]. In our case, the patient experienced progressive postoperative neurological deficits leading to a revision surgery. The early MRI highlighted a typical image of spinal cord kinking that can occurred after deformity correction. The early neurological complication prompted us to perform a surgical revision in order to reduce the spinal cord kinking by releasing the reduction. Postoperative recovery was immediately favorable with a normal aspect of spinal cord on the MRI (Fig. 5 ). This would suggest that the previous reduction of 115.2° was probably too high. The degree of correction in multiple PSO procedure is a critical factor that must be carefully considered to avoid neurological deficits. However, it remains difficult to estimate the approximate expected degree of correction as there is no universally accepted standard or guideline for this procedure. Additionally, the amount of reduction that can be safely achieved depends on several patient-specific factors, including the severity of the spinal deformity, its rigidity and the level and extent of the osteotomies. These factors can make it challenging to predict the approximate degree of correction and to ensure that it is achieved safely. In our case, the revision surgery allowed a total neurological recovery with a reduction that remained significant at 82.5°. Although the rate of complications following a multilevel PSO procedure can be as high as 30%, it is noteworthy that the majority of patients remain satisfied with the outcomes of the surgery. In fact, studies have shown that up to 76% of patients report being satisfied with the results of their PSO procedure despite experiencing complications [ 5 , 8 ]. It is important to note that patient satisfaction is a complex and multifactorial outcome that can be influenced by several factors beyond just the surgical outcome itself. For example, factors such as good communication with the surgical team, realistic expectations, and postoperative rehabilitation can all contribute to a patient's overall satisfaction with their surgical experience [ 8 ]. In our study, the patient was satisfied being able to ambulate without walker and having a horizontal gaze which improved her quality of life. Furthermore, the patient stated that would be ready to undergo this complex surgery again if she had to. Overall, while the high rate of complications associated with PSO procedures is certainly a concern, it is important to consider the impact of the surgery on the patient's quality of life and overall satisfaction with the outcome. The surgery of hyperkyphotic spine due to osteoporosis fracture can be challenging due to several factors [ 1 ]. One of the main challenges in treating these spinal deformities is the frailty of the bones. The vertebrae may be too weak to support spinal instrumentation and reduction maneuvers, and the risk of further fractures in adjacent segments is higher after surgery. Additionally, the presence of osteoporosis can make spinal fusion more difficult to achieve, as the bone may not fuse as well as it would in a healthy spine. To decrease implant failure in our case, several strategies were applied. First, specific implants were utilized: larger screws to distribute the load more evenly across the bone and cement augmentation to increase the screw-vertebra interface and improve fixation in osteoporotic bone. Second, a long segmental fixation was performed with 4 vertebras above and 6 below the multiple PSO to provide strong anchoring for deformity correction, reduce stress on adjacent segments, and prevent adjacent segment disease [ 5 ]. Another challenge in treating osteoporotic spine is the potential for additional complications. In fact, Patients with osteoporosis frequently have other comorbidities that may increase the risk of complications during surgery, such as cardiovascular disease or diabetes [ 2 ]. In our case, it was decided to perform a two-stage spine surgery to reduce operative time and blood loss, minimize the risk of complications, and ensure patient safety. However, the decision to perform a two-stage surgery depends on several factors, including the extent of the osteoporosis, the patient's overall health status, and the specific surgical goals. A thorough evaluation and careful surgical planning can help determine the optimal approach for each individual patient. CONCLUSION To the best of our knowledge, this is the first report to describe the use of 4 levels pedicle subtraction osteotomy for the management of severe rigid thoracic hyperkyphosis and showing that this complex surgical intervention can be an effective option for a carefully selected patient. Despite the occurrence of a typical spinal cord kinking, related to the accumulated shortening at 4 levels, applying 4 contiguous PSOs achieved satisfactory radiological and clinical outcome, and avoided the need for multiple level vertebral column resection with its associated higher level of complications. Declarations LEVEL OF EVIDENCE: IV (Case Report) Written informed consent was obtained from the patient for publication of this case report and any accompanying images Funding: The authors received no funding for this study. Conflicts of interest: The authors declare that they have no conflicts of interest. Ethics approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Written informed consent was obtained from the patient for publication of this case and the accompanying images. Author Contribution C.R. conceptualized the study, assisted to the surgery, and wrote the main manuscript draft.A.B. and L.B. contributed to surgical planning and provided technical review of the manuscript.L.D. contributed to data collection, radiographic analysis, and manuscript editing.I.O. supervised the project, performed the surgery, reviewed all drafts, and provided critical revisions.All authors reviewed and approved the final manuscript. References Hernlund E, Svedbom A, Ivergård M et al (2013) Osteoporosis in the European Union: medical management, epidemiology and economic burden. A report prepared in collaboration with the International Osteoporosis Foundation (IOF) and the European Federation of Pharmaceutical Industry Associations (EFPIA). Arch Osteoporos 8:136. https://doi.org/10.1007/s11657-013-0136-1 Cortet B, Houvenagel E, Puisieux F et al (1999) Spinal curvatures and quality of life in women with vertebral fractures secondary to osteoporosis. Spine 24:1921–1925. https://doi.org/10.1097/00007632-199909150-00010 Bradford DS, Moe JH, Montalvo FJ, Winter RB (1974) Scheuermann’s kyphosis and roundback deformity. Results of Milwaukee brace treatment. J Bone Joint Surg Am 56:740–758 Garg B, Bansal T, Mehta N (2021) Clinical, radiological, and functional outcomes of posterior-only three-column osteotomy in congenital kyphosis: a minimum of two years’ follow-up. Bone Jt J 103–B:1309–1316. https://doi.org/10.1302/0301-620X.103B7.BJJ-2020-2162.R1 Gill JB, Levin A, Burd T, Longley M (2008) Corrective Osteotomies in Spine Surgery. J Bone Jt Surg-Am Vol 90:2509–2520. https://doi.org/10.2106/JBJS.H.00081 Papadopoulos EC, Boachie-Adjei O, Hess WF et al (2015) Early outcomes and complications of posterior vertebral column resection. Spine J Off J North Am Spine Soc 15:983–991. https://doi.org/10.1016/j.spinee.2013.03.023 Obeid I, Boissière L, Vital J-M, Bourghli A (2015) Osteotomy of the spine for multifocal deformities. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc 24(Suppl 1):S83–92. https://doi.org/10.1007/s00586-014-3660-9 Dorward IG, Lenke LG (2010) Osteotomies in the posterior-only treatment of complex adult spinal deformity: a comparative review. Neurosurg Focus 28:E4. https://doi.org/10.3171/2009.12.FOCUS09259 Obeid I, Boissière L, Yilgor C et al (2016) Global tilt: a single parameter incorporating spinal and pelvic sagittal parameters and least affected by patient positioning. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc 25:3644–3649. https://doi.org/10.1007/s00586-016-4649-3 Yilgor C, Sogunmez N, Boissiere L et al (2017) Global Alignment and Proportion (GAP) Score: Development and Validation of a New Method of Analyzing Spinopelvic Alignment to Predict Mechanical Complications After Adult Spinal Deformity Surgery. J Bone Joint Surg Am 99:1661–1672. https://doi.org/10.2106/JBJS.16.01594 Bourghli A, Boissière L, Konbaz F et al (2021) On the pedicle subtraction osteotomy technique and its modifications during the past two decades: a complementary classification to the Schwab’s spinal osteotomy classification. Spine Deform 9:515–528. https://doi.org/10.1007/s43390-020-00247-6 Bourghli A, Boissiere L, Konbaz F et al (2023) Domino connector for thoracic pedicle subtraction osteotomy reduction: surgical technique and patient series. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc. https://doi.org/10.1007/s00586-023-07650-3 Schwab F, Blondel B, Chay E et al (2014) The comprehensive anatomical spinal osteotomy classification. Neurosurgery 74:112–120 discussion 120. https://doi.org/10.1227/NEU.0000000000000182o Bourghli A, Boissiere L, Obeid I (2021) T12 pedicle subtraction osteotomy for post-laminectomy kyphoscoliotic deformity following resection of a thoracolumbar astrocytoma in an adolescent with a previous paraplegic context. Spine Deform 9:275–283. https://doi.org/10.1007/s43390-020-00206-1 Bourghli A, Abduljawad SM, Boissiere L, Obeid I (2020) Thoracolumbar kyphoscoliotic deformity with neurological impairment secondary to a butterfly vertebra in an adult. Spine Deform 8:819–827. https://doi.org/10.1007/s43390-020-00050-3 Macagno AE, O’Brien MF (2006) Thoracic and thoracolumbar kyphosis in adults. Spine 31:S161–170. https://doi.org/10.1097/01.brs.0000236909.26123.f8 Suk S-I, Kim J-H, Kim W-J et al (2002) Posterior vertebral column resection for severe spinal deformities. Spine 27:2374–2382. https://doi.org/10.1097/00007632-200211010-00012 Lau D, Haddad AF, Fury MT et al (2021) Multilevel Pedicle Subtraction Osteotomy for Correction of Severe Rigid Adult Spinal Deformities: A Case Series, Indications, Considerations, and Literature Review. Oper Neurosurg Hagerstown Md 20:343–354. https://doi.org/10.1093/ons/opaa419 Cacho-Rodrigues P, Campana M, Obeid I et al (2016) Sagittal Correction and Reciprocal Changes After Thoracic Pedicle Subtraction Osteotomy. Spine 41:E791–E797. https://doi.org/10.1097/BRS.0000000000001386 Zhang HQ, Huang J, Guo CF et al (2014) Two-level pedicle subtraction osteotomy for severe thoracolumbar kyphotic deformity in ankylosing spondylitis. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc 23:234–241. https://doi.org/10.1007/s00586-013-2867-5 Xu H, Zhang Y, Zhao Y et al (2015) Radiologic and clinical outcomes comparison between single- and two-level pedicle subtraction osteotomies in correcting ankylosing spondylitis kyphosis. Spine J Off J North Am Spine Soc 15:290–297. https://doi.org/10.1016/j.spinee.2014.09.014 Bridwell KH, Lewis SJ, Edwards C et al (2003) Complications and outcomes of pedicle subtraction osteotomies for fixed sagittal imbalance. Spine 28:2093–2101. https://doi.org/10.1097/01.BRS.0000090891.60232.70 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 08 Jan, 2026 Read the published version in European Spine Journal → Version 1 posted Editorial decision: Revision requested 08 Dec, 2025 Reviews received at journal 05 Dec, 2025 Reviewers agreed at journal 03 Dec, 2025 Reviewers agreed at journal 03 Dec, 2025 Reviewers invited by journal 03 Dec, 2025 Editor assigned by journal 26 Nov, 2025 Submission checks completed at journal 26 Nov, 2025 First submitted to journal 21 Nov, 2025 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8172930","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":554928238,"identity":"3c1a25d6-d60f-4c9b-b590-682c9ee97aed","order_by":0,"name":"Cécile Roscop","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYHADxsYDDBVAmpm5gWgtDQcYzoC0MBKthYHhAGMbRC9eVebt7Q8/fNzBIM/PfrjhwMd5tdH87UAtPyq24dQic+aMseTMMwyGM3sSGw7O3HY8d8ZhxgbGnjO3cWqRkMhhY+ZtY0gwuMHYcJh327HcBqAWZsY2fFrSn4G12IO0/J1zLHc+YS0JZhBbJBhB5tfkbiCohQfsFwnDGWeAfuk5diB3I1DLQbx+YQeHmI08f/vxhw9+1NTlzjt/+OCDHxW4tYABY4MEjHkYTB7Ar54BJe7qCCoeBaNgFIyCkQcASONcnP7/DZwAAAAASUVORK5CYII=","orcid":"","institution":"Polyclinic Jean Villar","correspondingAuthor":true,"prefix":"","firstName":"Cécile","middleName":"","lastName":"Roscop","suffix":""},{"id":554928242,"identity":"edb1b463-0878-45c2-89e1-e7fa7aaef99c","order_by":1,"name":"Anouar Bourghli","email":"","orcid":"","institution":"King Faisal University","correspondingAuthor":false,"prefix":"","firstName":"Anouar","middleName":"","lastName":"Bourghli","suffix":""},{"id":554928243,"identity":"c9e85df8-fcd6-4c59-9474-288aee7c0eca","order_by":2,"name":"Daniel Larrieu","email":"","orcid":"","institution":"Polyclinic Jean Villar","correspondingAuthor":false,"prefix":"","firstName":"Daniel","middleName":"","lastName":"Larrieu","suffix":""},{"id":554928244,"identity":"3f8f5a59-ae4b-4fc5-9fde-9bade34175fd","order_by":3,"name":"Louis Boissière","email":"","orcid":"","institution":"Polyclinic Jean Villar","correspondingAuthor":false,"prefix":"","firstName":"Louis","middleName":"","lastName":"Boissière","suffix":""},{"id":554928245,"identity":"f9762f54-497b-426a-98be-5924aa10b50c","order_by":4,"name":"Ibrahim Obeid","email":"","orcid":"","institution":"Polyclinic Jean Villar","correspondingAuthor":false,"prefix":"","firstName":"Ibrahim","middleName":"","lastName":"Obeid","suffix":""}],"badges":[],"createdAt":"2025-11-21 11:08:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8172930/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8172930/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00586-025-09734-8","type":"published","date":"2026-01-08T15:57:29+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":97687515,"identity":"6e0ebdb8-0553-4fc5-9163-dc677f4c488c","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":153246,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/1fbe186ac7cb3c7b9bf8cb02.docx"},{"id":97893366,"identity":"be09b9e0-aefe-464d-864e-e8a6f8f443cb","added_by":"auto","created_at":"2025-12-10 15:30:13","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72417,"visible":true,"origin":"","legend":"","description":"","filename":"BlindedManuscrit.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/fa4dda82aa1d7441c59caa08.docx"},{"id":97893528,"identity":"792c551c-408b-4098-8dae-6b6072e7eac1","added_by":"auto","created_at":"2025-12-10 15:30:39","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":502697,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/b252f80b72f6327a4c3a16e8.docx"},{"id":97687520,"identity":"884e1c0f-96f7-4d66-9d1d-c489fd5cde1d","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":515310,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/1d2e0b16802064320ab4e26a.docx"},{"id":97687524,"identity":"9a459299-2af8-40be-880f-95d2e5657fee","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":3626625,"visible":true,"origin":"","legend":"","description":"","filename":"Figure4.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/88ad7303615a6aed34557099.docx"},{"id":97893813,"identity":"8b9a31f8-99f8-48c2-8ceb-d36b366e5b06","added_by":"auto","created_at":"2025-12-10 15:31:17","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":611607,"visible":true,"origin":"","legend":"","description":"","filename":"Figure5.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/7ebcef89961666ea1541b770.docx"},{"id":97893741,"identity":"3a865faa-d3c2-49f5-ad64-43632d9fa574","added_by":"auto","created_at":"2025-12-10 15:31:07","extension":"docx","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":165161,"visible":true,"origin":"","legend":"","description":"","filename":"Figure6.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/741fcae8daca64420a9dcb13.docx"},{"id":97893826,"identity":"fc22992c-555c-4554-8b33-88475fa9f6ea","added_by":"auto","created_at":"2025-12-10 15:31:18","extension":"docx","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":166767,"visible":true,"origin":"","legend":"","description":"","filename":"Figure7.docx","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/ab78c29b22d52c90c8b6af34.docx"},{"id":97687519,"identity":"0f4feb4d-4f36-49d0-ad38-536c13bd2686","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"json","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":6530,"visible":true,"origin":"","legend":"","description":"","filename":"2a80cc5a8ebb41df962462693c3b0d00.json","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/13ab69719d8792c1f9108475.json"},{"id":97893564,"identity":"833e4818-fd42-41a0-a72b-24e782736329","added_by":"auto","created_at":"2025-12-10 15:30:44","extension":"xml","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":65692,"visible":true,"origin":"","legend":"","description":"","filename":"2a80cc5a8ebb41df962462693c3b0d001enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/6be71aaed8ea4c3fb9601367.xml"},{"id":97687526,"identity":"fb455bd8-d54f-4e74-ab3a-6d948de4ac5d","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"jpeg","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":285884,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/303df6f1666fb686010066ad.jpeg"},{"id":97893313,"identity":"a0ab7614-2d52-4fa2-9de0-2df8e868123a","added_by":"auto","created_at":"2025-12-10 15:29:55","extension":"png","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":488500,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/a7e5d2d17cae2774854c8c0a.png"},{"id":97893551,"identity":"201d25bc-7f28-410f-857e-04e223676173","added_by":"auto","created_at":"2025-12-10 15:30:42","extension":"jpeg","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":836562,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/035a0a1ab23eec5ceaedb6eb.jpeg"},{"id":97687532,"identity":"7686ecd6-46f6-4110-b1c9-0a511e95f2e4","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1690172,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/adb74535fe45846fa296098a.png"},{"id":97892656,"identity":"3eee2cb7-c858-48bc-a25f-a1a6812c55b2","added_by":"auto","created_at":"2025-12-10 15:17:02","extension":"png","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1921127,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/35a422f8c911178028e65d9b.png"},{"id":97893997,"identity":"2a689338-be28-4df2-9d9e-fd1803f700a7","added_by":"auto","created_at":"2025-12-10 15:31:46","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":596514,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/5e5b10488c301ef1882dfd35.png"},{"id":97893505,"identity":"f980df52-ae20-41e9-bfcf-230db3fd2e6f","added_by":"auto","created_at":"2025-12-10 15:30:37","extension":"jpeg","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":644067,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/ed337aa4251675db8b7d2b3f.jpeg"},{"id":97893526,"identity":"c30244e7-2ca3-4a2a-b1fc-f8e65fbacec5","added_by":"auto","created_at":"2025-12-10 15:30:39","extension":"jpeg","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":436622,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/d119fa5535a3a1dca1b1371d.jpeg"},{"id":97893524,"identity":"dc2acd65-1a0e-4235-ad59-5f70928fed48","added_by":"auto","created_at":"2025-12-10 15:30:39","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":431211,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/19997523b304dc741fc9589f.png"},{"id":97687529,"identity":"17039384-d763-4090-b983-4a3874ec9175","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"png","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":102820,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/2c9a35e13542ead12781d001.png"},{"id":97687534,"identity":"ac9a58fc-e6b2-4990-8da9-81a9e4c27e7b","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"png","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":243969,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/640ec9e9121ca91ea55a234d.png"},{"id":97687544,"identity":"40281ae5-a2d7-478b-ae98-ba7a0381ca93","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"png","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":260772,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/051aeee4eb6630dd40bd2f23.png"},{"id":97893868,"identity":"828251d8-e61a-4c7f-bdb0-a2fc2597467e","added_by":"auto","created_at":"2025-12-10 15:31:23","extension":"png","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":268647,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/90a40713c7150b5ae13a7ac1.png"},{"id":97893447,"identity":"659fb822-9227-44f2-a15f-72e4160bc4e3","added_by":"auto","created_at":"2025-12-10 15:30:27","extension":"png","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":83536,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/3b25da1e16a31e0b4341570d.png"},{"id":97687540,"identity":"b435dd0a-56f3-46db-b423-97ceb0449aae","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"png","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":128595,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/a4405c827d308eab870d7b01.png"},{"id":97687543,"identity":"4c7ab9ef-c432-4af2-a571-185ad9fe5971","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"png","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":757496,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/84674e9f9ad4bb4238b74241.png"},{"id":97893431,"identity":"82f53dca-cb84-46a7-9cea-7737b8f3d11a","added_by":"auto","created_at":"2025-12-10 15:30:25","extension":"xml","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":62037,"visible":true,"origin":"","legend":"","description":"","filename":"2a80cc5a8ebb41df962462693c3b0d001structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/187ee9d9833cf53f4ff36f7b.xml"},{"id":97687542,"identity":"3641991a-d689-4b8d-9ddf-85aca46b6a43","added_by":"auto","created_at":"2025-12-08 10:26:01","extension":"html","order_by":27,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":70988,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/fda2ee2e2e61877db517f8ba.html"},{"id":97687509,"identity":"a36359cb-ecda-4cce-b345-0ea68652593d","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":48136,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative full spine anteroposterior and lateral X-rays revealing a thoracic kyphosis with an angulation of 130,3° between T4 and T12, with global sagittal malalignment.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/981e26020eaa0305f436619c.jpg"},{"id":97687518,"identity":"bc304edc-bada-4e15-80cf-f9bae25c9777","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":87047,"visible":true,"origin":"","legend":"\u003cp\u003eInitial CT- Scan (a) and MRI (b) before the first surgery showing the importance of thoracic kyphosis due to multiple osteoporotic fractures.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/8ffc26ef5d7401d45875cb41.jpg"},{"id":97687511,"identity":"4e5a9d89-ce83-4795-b6c3-bb362991282d","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":112391,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative picture highlighting the importance of the thoracic kyphosis angulation making positioning and surgical approach difficult.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/d9ac2fd4676f4960a0c61d58.jpg"},{"id":97893841,"identity":"2a24e145-4260-474b-815c-3f4a6c5a7800","added_by":"auto","created_at":"2025-12-10 15:31:21","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":258272,"visible":true,"origin":"","legend":"\u003cp\u003eIntraoperative picture showing the multiple PSOs(A). Per-operative picture after reduction by external maneuver and definitive prebent rod (B).\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/b4bb527406e8755f42a18397.jpg"},{"id":97893601,"identity":"16249a07-d908-466c-a569-b3f3b11fe4ba","added_by":"auto","created_at":"2025-12-10 15:30:50","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":111768,"visible":true,"origin":"","legend":"\u003cp\u003eEarly MRI after the second-stage surgery with spinal cord kinking explaining postoperative limb weakness (A). Postoperative MRI after revision surgery showing decreased correction and normalization of the cord aspect (B).\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/8b3ece9a23cbd27d0c256737.jpg"},{"id":97893548,"identity":"e7218aa1-cf2b-4e90-adad-4620cd6267d3","added_by":"auto","created_at":"2025-12-10 15:30:42","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":94396,"visible":true,"origin":"","legend":"\u003cp\u003eStanding full spine EOS imaging at 6 months postoperatively showing satisfactory correction of the thoracic kyphosis (reduction of 82.5°) and improved global sagittal alignment.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/de732d59e38653ade192b864.jpg"},{"id":97687513,"identity":"e1e76a43-83d7-4406-9b4d-ac112c9f8b40","added_by":"auto","created_at":"2025-12-08 10:26:00","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":57835,"visible":true,"origin":"","legend":"\u003cp\u003eTwo-year follow-up CT scan showing the stability of the construct without any fracture of implants or screw dislodgement that could raise concerns about non-union.\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/e4711dbf4fbff9839b95da9a.jpg"},{"id":100069355,"identity":"5d170ea6-4100-46ed-834b-7be097a45da3","added_by":"auto","created_at":"2026-01-12 16:13:12","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1163926,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8172930/v1/e7f0f8af-ea42-43bc-a3ff-a55b8fef2690.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Four-Level Pedicle Subtraction Osteotomy for Severe Rigid Thoracic Hyperkyphosis: A Technical Case Report","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eSevere thoracic hyperkyphosis is a disabling condition that can result from congenital conditions, however it may be the consequence of multiple osteoporotic fractures of the vertebrae. This latter condition can lead to significant pain, disability, and decreased quality of life [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. While conservative measures such as bracing and medical treatment may be effective in some cases [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], more severe and rigid deformities may require surgical intervention. The multilevel pedicle subtraction osteotomy (PSO) is a complex surgical technique used to correct severe adult spinal deformities such as thoracic hyperkyphosis. This procedure involves vertebral body osteotomy at one or more segments, followed by spinal shortening and fusion [\u003cspan additionalcitationids=\"CR5 CR6 CR7\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. To our knowledge, this is the first study which presents a four-level PSO procedure for the treatment of a patient with severe and rigid thoracic hyperkyphosis resulting from multiple osteoporotic fractures. This report aims to describe the technical aspects of the surgery, outcomes, and potential complications associated with this procedure.\u003c/p\u003e"},{"header":"CASE REPORT","content":"\u003cp\u003eA 65-year-old female patient known for Scheuermann's disease since childhood was referred to our spine unit for the treatment of an extremely severe thoracic hyperkyphosis. Her thoracic kyphosis progressively worsened due to osteoporotic vertebral fractures at the apical thoracic area (lumbar T-score \u0026minus;\u0026thinsp;3.9) despite regular follow-up in the rheumatology department. The patient suffered a decrease in her quality of life as well as respiratory discomfort. Standing was only possible for a few minutes, and the seated position made it impossible to maintain horizontal gaze. She had an ODI disability score of 65. Due to the severity of osteoporosis, treatment with alendronate was initiated 6 months prior to surgery.\u003c/p\u003e\u003cp\u003eClinical examination revealed severe upper thoracic kyphotic deformity associated with low back pain, due to facet joint syndrome because of compensatory hyperlordosis. She required a walker frame for ambulation. Neurological evaluation shows normal motor and sensory function, no bowel or bladder dysfunction, reflexes were normal.\u003c/p\u003e\u003cp\u003ePreoperative full-spine X-ray showed a pelvic incidence of 43,1\u0026deg;, a pelvic tilt of 28,0\u0026deg;, a thoracic kyphosis T4T12 of 130,3\u0026deg;, a lumbar lordosis of 45,7\u0026deg;, a SVA at -27 mm and a global tilt angle of 31,5\u0026deg;(Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], showing a severe sagittal malalignment [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Supine traction x-rays showed a non-flexible rigid kyphosis.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eCT scan and MRI confirmed the deformity with the presence of multiple healed osteoporotic fractures (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eGiven the severity of the deformity, its progressive worsening, as well as the major impact on the quality of life despite conservative treatments, the patient underwent corrective surgery with a single-posterior approach with vertebral Pedicle subtraction osteotomy at 4 levels from T6 to T9 (Grade 4B and 4C according to the classification described by Bourghli[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]) with instrumentation from T2 to L3.\u003c/p\u003e\u003cp\u003eSuch procedure is complex and challenging for two reasons: the severity of the thoracic kyphosis measured at 130.3\u0026deg;, and the presence of severe osteoporosis with high-risk of mechanical failure of the instrumentation. Thorough assessment and planning, it was decided to perform the surgery in two stages: a first-stage for the insertion of the instrumentation with cement-augmented screws, and a second-stage for the osteotomies and deformity correction.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eSurgical technique\u003c/h2\u003e\u003cp\u003eUnder general anesthesia, the patient was positioned in a prone position (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The head was fixed in a Mayfield clamp to facilitate installation and allow external reduction maneuver. A computer-assisted navigation system (O-arm Surgical Imaging with StealthStation, Medtronic, Minneapolis, MN) and neurophysiological monitoring with somatosensory-evoked potentials and transcranial motor-evoked potentials were used in both surgical stages.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe objective of the first-stage was to perform the approach and insert implants. Through a posterior midline incision, a subperiosteal dissection was carried out, exposing the posterior spinal elements. After fluoroscopic confirmation of the correct level, pedicle screws were inserted from T2 to T5 proximally with the assistance of the navigation and T10 to L3 distally by using the free-hand technique. All pedicle screws were cemented to avoid implant failure. No release maneuvers were performed at this stage. The surgery lasted 3h hours. Estimated blood loss was approximately 300 mL. Neurological monitoring showed no change.\u003c/p\u003e\u003cp\u003eThe second-stage was performed one week later. In order to obtain a satisfactory correction, it was decided to perform 4 level contiguous PSOs at the apex of the thoracic kyphosis including T6, T7, T8 and T9.\u003c/p\u003e\u003cp\u003eA revision of the previous incision was made. The different steps of the PSO technique are described in the following paragraph. It was first performed at (T6) and then repeated at the other levels (T7, T8 and T9).\u003c/p\u003e\u003cp\u003ePreparatory holes were made in the pedicles at each level of the osteotomy PSO level, as guidance for the osteotomy. Costotransverse joint and rib were exposed bilaterally. The rib was cut two centimeters laterally from the costotransverse joint. The neurovascular bundle was preserved and particular attention was paid to not violate the parietal pleura.\u003c/p\u003e\u003cp\u003eAfter transverse processes resection, the rib heads were disarticulated allowing exposure of the lateral part of the vertebral body. A cobb elevator was placed on the lateral wall bilaterally to retract the lateral soft tissues. A wide laminectomy was performed, as well as bilateral foraminotomies cephalad and caudal to the pedicle. Pedicles and the vertebral body were progressively removed using rongeurs, curettes, and high-speed drilling. Three osteotomes were used to perform the transpedicular wedge osteotomy. Proximal disc was resected with a curette in order to obtain bone on bone contact. The posterior wall of the vertebral body was anteriorly impacted by a dedicated osteotome and impactor. Proximal level laminotomy was performed to mechanically allow the closure of the osteotomy, thus avoiding and decreasing dural kinking risks (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAfter performing the osteotomies at each level, pre-bent rods were gently and progressively persuaded into the screws. A domino system was used for the reduction which involved simultaneous internal and external maneuvers. the external maneuver mobilized the patient's head in extension using the Mayfield clamp, and the internal maneuver applied cantilevering on the proximal and distal rods with compression on the domino achieving satisfactory closure with bone on bone contact [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] ((Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). To achieve fusion, local autologous morselized graft mixed with vancomycin powder was placed after decortication of the spinal posterior elements.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eNeurophysiological monitoring with somatosensory-evoked potentials and transcranial motor-evoked potentials did not show any modifications\u003c/p\u003e\u003cp\u003eThe operating time was 3h15min, blood loss was 1650 mL. The patient spent her first night in intensive care unit. Immediate postoperative CT scan was done and showed a thoracic kyphosis T4T12 of 15.1, with a reduction of 115.2\u0026deg;.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003ePostoperative course\u003c/h3\u003e\n\u003cp\u003eAfter surgery, the patient's neurological condition, wound status, and pulmonary function were closely monitored. She started to present motor weakness of her right lower limb, which appeared progressively over several hours and became significant at 72 hours. A postoperative MRI was able to highlight an unexpectedly tortuous spinal cord at the osteotomy levels, Explaining poor neurological tolerance after spinal shortening (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). An immediate revision surgery was performed in order to decrease the reduction and check spinal cord release. The neurological improvement was immediately visible upon awakening.\u003c/p\u003e\u003cp\u003eThe patient was discharged from the hospital after 2 weeks following spine surgery with the use of a walking frame for ambulation. The patient reported an increase in quality of life following the surgery (ODI 39), with decreased pain and improved mobility. Radiological parameters also showed significant improvement, with a reduction in thoracic hyperkyphosis of 82.5\u0026deg; (preoperative TK 130.3\u0026deg; and post operative TK 47.8\u0026deg;) and improved spinal alignment: SVA 5mm, GT 24,0\u0026deg;, PT 21,2\u0026deg;, LL L1S1 39,8\u0026deg; (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e), which meant proportioned sagittal balance.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe patient demonstrated excellent progress following the surgery, with no major complications observed during the follow-up period and independent walking after 6 months. 2 years CT scan confirmed complete fusion at the osteotomy sites with no signs of implant failure. Radiological parameters remained unchanged on the 2 years full spine X-rays: KT T4T12 48,0\u0026deg;, GT 25,1\u0026deg;, PT 21,6\u0026deg;, L1S1 41,4\u0026deg;.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003ePerforming multiple PSOs in a single patient is a complex surgical technique used to correct severe spinal deformities such as thoracic hyperkyphosis [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOur case report describes a satisfactory outcome of a four-level PSO procedure for the treatment of a patient with severe and rigid thoracic hyperkyphosis due to multiple osteoporotic fractures. Such procedure is typically reserved for patients with severe and rigid spinal deformities that cannot be corrected with more conservative measures such as bracing or medical treatment. It is based on careful patient selection, thorough preoperative planning, and should be performed only within a setting used to complex spinal deformity management.\u003c/p\u003e\u003cp\u003eSeveral authors described different algorithms to determine the proper technique of correction depending on thoracic kyphosis value, rigidity of the deformity and the sagittal imbalance [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Three-column osteotomies such as vertebral column resection (VCR) or PSO are powerful methods of focal rigid thoracic deformity correction [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and has been suggested as correcting procedures when the deformity is not amenable to other osteotomy techniques such as Ponte or posterior column osteotomies [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e][\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e][\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. VCR is a highly effective technique for correcting severe spinal deformities, offering significant correction and restoration of spinal alignment. However, due to its inherent high risks and potential complications, this surgical procedure has been primarily advised for pediatric cases where the potential benefits outweigh the risks[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In elderly patients or those with compromised bone quality, PSO is often favored as a less aggressive alternative. Multilevel VCR often requires a structural cage or extent bone graft for anterior support to prevent risks of spinal cord kinking and malunion. Whereas PSO can produce substantial correction at a single level, with high union rate due to the bone on bone contact at the osteotomy closure site, without the need of an anterior support (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMultilevel noncontiguous PSO has established itself as a well-recognized surgical tool for correcting adult spinal deformities, such as Scheuermann disease or ankylosing spondylitis, with the aim of achieving improved good distribution of sagittal balance[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e][\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Additionally, multiple-level PSO helps distribute the corrective forces across a larger segment of the spine. This distributed correction reduces the risk of placing excessive stress on a single osteotomy site, minimizing the chances of hardware failure and nonunion. Literature is scarce about multiple level PSO, mainly describing noncontiguous PSO in adult spinal deformities [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Lau and al. presented two-level noncontiguous PSO in upper thoracic spine and midthoracic spine which provide 88\u0026deg; and 68\u0026deg; of TK correction respectively[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. To our knowledge, no previous study described a four-level contiguous PSO in the elderly patient with osteoporosis comorbidity.\u003c/p\u003e\u003cp\u003eOur patient\u0026rsquo;s postoperative imaging showed a significant correction of the spinal deformity, as well as improved pulmonary function. However, the procedure was not without risks, as demonstrated by the onset of progressive postoperative lower limb weakness. Authors in the literature found a 30% rate of early complications, including 8% with neurological deficits requiring further decompression [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e][\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In our case, the patient experienced progressive postoperative neurological deficits leading to a revision surgery. The early MRI highlighted a typical image of spinal cord kinking that can occurred after deformity correction. The early neurological complication prompted us to perform a surgical revision in order to reduce the spinal cord kinking by releasing the reduction. Postoperative recovery was immediately favorable with a normal aspect of spinal cord on the MRI (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). This would suggest that the previous reduction of 115.2\u0026deg; was probably too high. The degree of correction in multiple PSO procedure is a critical factor that must be carefully considered to avoid neurological deficits. However, it remains difficult to estimate the approximate expected degree of correction as there is no universally accepted standard or guideline for this procedure. Additionally, the amount of reduction that can be safely achieved depends on several patient-specific factors, including the severity of the spinal deformity, its rigidity and the level and extent of the osteotomies. These factors can make it challenging to predict the approximate degree of correction and to ensure that it is achieved safely. In our case, the revision surgery allowed a total neurological recovery with a reduction that remained significant at 82.5\u0026deg;.\u003c/p\u003e\u003cp\u003eAlthough the rate of complications following a multilevel PSO procedure can be as high as 30%, it is noteworthy that the majority of patients remain satisfied with the outcomes of the surgery. In fact, studies have shown that up to 76% of patients report being satisfied with the results of their PSO procedure despite experiencing complications [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. It is important to note that patient satisfaction is a complex and multifactorial outcome that can be influenced by several factors beyond just the surgical outcome itself. For example, factors such as good communication with the surgical team, realistic expectations, and postoperative rehabilitation can all contribute to a patient's overall satisfaction with their surgical experience [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In our study, the patient was satisfied being able to ambulate without walker and having a horizontal gaze which improved her quality of life. Furthermore, the patient stated that would be ready to undergo this complex surgery again if she had to. Overall, while the high rate of complications associated with PSO procedures is certainly a concern, it is important to consider the impact of the surgery on the patient's quality of life and overall satisfaction with the outcome.\u003c/p\u003e\u003cp\u003eThe surgery of hyperkyphotic spine due to osteoporosis fracture can be challenging due to several factors [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. One of the main challenges in treating these spinal deformities is the frailty of the bones. The vertebrae may be too weak to support spinal instrumentation and reduction maneuvers, and the risk of further fractures in adjacent segments is higher after surgery. Additionally, the presence of osteoporosis can make spinal fusion more difficult to achieve, as the bone may not fuse as well as it would in a healthy spine. To decrease implant failure in our case, several strategies were applied. First, specific implants were utilized: larger screws to distribute the load more evenly across the bone and cement augmentation to increase the screw-vertebra interface and improve fixation in osteoporotic bone. Second, a long segmental fixation was performed with 4 vertebras above and 6 below the multiple PSO to provide strong anchoring for deformity correction, reduce stress on adjacent segments, and prevent adjacent segment disease [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAnother challenge in treating osteoporotic spine is the potential for additional complications. In fact, Patients with osteoporosis frequently have other comorbidities that may increase the risk of complications during surgery, such as cardiovascular disease or diabetes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. In our case, it was decided to perform a two-stage spine surgery to reduce operative time and blood loss, minimize the risk of complications, and ensure patient safety. However, the decision to perform a two-stage surgery depends on several factors, including the extent of the osteoporosis, the patient's overall health status, and the specific surgical goals. A thorough evaluation and careful surgical planning can help determine the optimal approach for each individual patient.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eTo the best of our knowledge, this is the first report to describe the use of 4 levels pedicle subtraction osteotomy for the management of severe rigid thoracic hyperkyphosis and showing that this complex surgical intervention can be an effective option for a carefully selected patient. Despite the occurrence of a typical spinal cord kinking, related to the accumulated shortening at 4 levels, applying 4 contiguous PSOs achieved satisfactory radiological and clinical outcome, and avoided the need for multiple level vertebral column resection with its associated higher level of complications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eLEVEL OF EVIDENCE: IV (Case Report)\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient for publication of this case report and any accompanying images\u003c/p\u003e\n\u003cp\u003eFunding: The authors received no funding for this study.\u003c/p\u003e\n\u003cp\u003eConflicts of interest: The authors declare that they have no conflicts of interest.\u003c/p\u003e\n\u003cp\u003eEthics approval: Not applicable.\u003c/p\u003e\n\u003cp\u003eConsent to participate: Not applicable.\u003c/p\u003e\n\u003cp\u003eConsent for publication: Written informed consent was obtained from the patient for publication of this case and the accompanying images.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eC.R. conceptualized the study, assisted to the surgery, and wrote the main manuscript draft.A.B. and L.B. contributed to surgical planning and provided technical review of the manuscript.L.D. contributed to data collection, radiographic analysis, and manuscript editing.I.O. supervised the project, performed the surgery, reviewed all drafts, and provided critical revisions.All authors reviewed and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHernlund E, Svedbom A, Iverg\u0026aring;rd M et al (2013) Osteoporosis in the European Union: medical management, epidemiology and economic burden. A report prepared in collaboration with the International Osteoporosis Foundation (IOF) and the European Federation of Pharmaceutical Industry Associations (EFPIA). Arch Osteoporos 8:136. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s11657-013-0136-1\u003c/span\u003e\u003cspan address=\"10.1007/s11657-013-0136-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCortet B, Houvenagel E, Puisieux F et al (1999) Spinal curvatures and quality of life in women with vertebral fractures secondary to osteoporosis. Spine 24:1921\u0026ndash;1925. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/00007632-199909150-00010\u003c/span\u003e\u003cspan address=\"10.1097/00007632-199909150-00010\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBradford DS, Moe JH, Montalvo FJ, Winter RB (1974) Scheuermann\u0026rsquo;s kyphosis and roundback deformity. Results of Milwaukee brace treatment. J Bone Joint Surg Am 56:740\u0026ndash;758\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGarg B, Bansal T, Mehta N (2021) Clinical, radiological, and functional outcomes of posterior-only three-column osteotomy in congenital kyphosis: a minimum of two years\u0026rsquo; follow-up. Bone Jt J 103\u0026ndash;B:1309\u0026ndash;1316. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1302/0301-620X.103B7.BJJ-2020-2162.R1\u003c/span\u003e\u003cspan address=\"10.1302/0301-620X.103B7.BJJ-2020-2162.R1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGill JB, Levin A, Burd T, Longley M (2008) Corrective Osteotomies in Spine Surgery. J Bone Jt Surg-Am Vol 90:2509\u0026ndash;2520. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2106/JBJS.H.00081\u003c/span\u003e\u003cspan address=\"10.2106/JBJS.H.00081\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePapadopoulos EC, Boachie-Adjei O, Hess WF et al (2015) Early outcomes and complications of posterior vertebral column resection. Spine J Off J North Am Spine Soc 15:983\u0026ndash;991. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.spinee.2013.03.023\u003c/span\u003e\u003cspan address=\"10.1016/j.spinee.2013.03.023\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eObeid I, Boissi\u0026egrave;re L, Vital J-M, Bourghli A (2015) Osteotomy of the spine for multifocal deformities. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc 24(Suppl 1):S83\u0026ndash;92. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00586-014-3660-9\u003c/span\u003e\u003cspan address=\"10.1007/s00586-014-3660-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDorward IG, Lenke LG (2010) Osteotomies in the posterior-only treatment of complex adult spinal deformity: a comparative review. Neurosurg Focus 28:E4. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3171/2009.12.FOCUS09259\u003c/span\u003e\u003cspan address=\"10.3171/2009.12.FOCUS09259\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eObeid I, Boissi\u0026egrave;re L, Yilgor C et al (2016) Global tilt: a single parameter incorporating spinal and pelvic sagittal parameters and least affected by patient positioning. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc 25:3644\u0026ndash;3649. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00586-016-4649-3\u003c/span\u003e\u003cspan address=\"10.1007/s00586-016-4649-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYilgor C, Sogunmez N, Boissiere L et al (2017) Global Alignment and Proportion (GAP) Score: Development and Validation of a New Method of Analyzing Spinopelvic Alignment to Predict Mechanical Complications After Adult Spinal Deformity Surgery. J Bone Joint Surg Am 99:1661\u0026ndash;1672. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2106/JBJS.16.01594\u003c/span\u003e\u003cspan address=\"10.2106/JBJS.16.01594\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBourghli A, Boissi\u0026egrave;re L, Konbaz F et al (2021) On the pedicle subtraction osteotomy technique and its modifications during the past two decades: a complementary classification to the Schwab\u0026rsquo;s spinal osteotomy classification. Spine Deform 9:515\u0026ndash;528. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s43390-020-00247-6\u003c/span\u003e\u003cspan address=\"10.1007/s43390-020-00247-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBourghli A, Boissiere L, Konbaz F et al (2023) Domino connector for thoracic pedicle subtraction osteotomy reduction: surgical technique and patient series. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00586-023-07650-3\u003c/span\u003e\u003cspan address=\"10.1007/s00586-023-07650-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSchwab F, Blondel B, Chay E et al (2014) The comprehensive anatomical spinal osteotomy classification. Neurosurgery 74:112\u0026ndash;120 discussion 120. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1227/NEU.0000000000000182o\u003c/span\u003e\u003cspan address=\"10.1227/NEU.0000000000000182o\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBourghli A, Boissiere L, Obeid I (2021) T12 pedicle subtraction osteotomy for post-laminectomy kyphoscoliotic deformity following resection of a thoracolumbar astrocytoma in an adolescent with a previous paraplegic context. Spine Deform 9:275\u0026ndash;283. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s43390-020-00206-1\u003c/span\u003e\u003cspan address=\"10.1007/s43390-020-00206-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBourghli A, Abduljawad SM, Boissiere L, Obeid I (2020) Thoracolumbar kyphoscoliotic deformity with neurological impairment secondary to a butterfly vertebra in an adult. Spine Deform 8:819\u0026ndash;827. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s43390-020-00050-3\u003c/span\u003e\u003cspan address=\"10.1007/s43390-020-00050-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMacagno AE, O\u0026rsquo;Brien MF (2006) Thoracic and thoracolumbar kyphosis in adults. Spine 31:S161\u0026ndash;170. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/01.brs.0000236909.26123.f8\u003c/span\u003e\u003cspan address=\"10.1097/01.brs.0000236909.26123.f8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSuk S-I, Kim J-H, Kim W-J et al (2002) Posterior vertebral column resection for severe spinal deformities. Spine 27:2374\u0026ndash;2382. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/00007632-200211010-00012\u003c/span\u003e\u003cspan address=\"10.1097/00007632-200211010-00012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLau D, Haddad AF, Fury MT et al (2021) Multilevel Pedicle Subtraction Osteotomy for Correction of Severe Rigid Adult Spinal Deformities: A Case Series, Indications, Considerations, and Literature Review. Oper Neurosurg Hagerstown Md 20:343\u0026ndash;354. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/ons/opaa419\u003c/span\u003e\u003cspan address=\"10.1093/ons/opaa419\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCacho-Rodrigues P, Campana M, Obeid I et al (2016) Sagittal Correction and Reciprocal Changes After Thoracic Pedicle Subtraction Osteotomy. Spine 41:E791\u0026ndash;E797. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/BRS.0000000000001386\u003c/span\u003e\u003cspan address=\"10.1097/BRS.0000000000001386\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang HQ, Huang J, Guo CF et al (2014) Two-level pedicle subtraction osteotomy for severe thoracolumbar kyphotic deformity in ankylosing spondylitis. Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc 23:234\u0026ndash;241. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00586-013-2867-5\u003c/span\u003e\u003cspan address=\"10.1007/s00586-013-2867-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXu H, Zhang Y, Zhao Y et al (2015) Radiologic and clinical outcomes comparison between single- and two-level pedicle subtraction osteotomies in correcting ankylosing spondylitis kyphosis. Spine J Off J North Am Spine Soc 15:290\u0026ndash;297. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.spinee.2014.09.014\u003c/span\u003e\u003cspan address=\"10.1016/j.spinee.2014.09.014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBridwell KH, Lewis SJ, Edwards C et al (2003) Complications and outcomes of pedicle subtraction osteotomies for fixed sagittal imbalance. Spine 28:2093\u0026ndash;2101. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/01.BRS.0000090891.60232.70\u003c/span\u003e\u003cspan address=\"10.1097/01.BRS.0000090891.60232.70\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Kyphosis, Osteotomy, Scheuermann Disease, Spinal Fusion, Spinal Curvatures","lastPublishedDoi":"10.21203/rs.3.rs-8172930/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8172930/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eStudy Design:\u003c/h2\u003e\u003cp\u003eTechnical case report\u003c/p\u003e\u003ch2\u003eIntroduction:\u003c/h2\u003e\u003cp\u003eSevere thoracic hyperkyphosis caused by multiple osteoporotic fractures can lead to significant disability. When deformities are rigid, surgical correction may be required. This report describes a rare case of four-level pedicle subtraction osteotomy (PSO) to address a fixed deformity, with focus on technique, outcomes, and complications.\u003c/p\u003e\u003ch2\u003eCase Presentation:\u003c/h2\u003e\u003cp\u003eA 65-year-old female with Scheuermann\u0026rsquo;s disease developed progressive thoracic hyperkyphosis due to osteoporotic vertebral fractures. Radiographs showed a rigid kyphosis of 130.3\u0026deg;. The patient underwent a two-stage surgery: cement-augmented instrumentation (T2\u0026ndash;L3), followed by contiguous PSOs from T6 to T9. Neurophysiological monitoring was used throughout.\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e\u003cp\u003eKyphosis was corrected from 130.3\u0026deg; to 48\u0026deg;. Postoperatively, the patient developed progressive lower limb weakness due to spinal cord kinking. Revision surgery allowed neurological recovery. At two years, radiological parameters remained stable, and the patient reported reduced pain, improved mobility, and restored quality of life.\u003c/p\u003e\u003ch2\u003eConclusion:\u003c/h2\u003e\u003cp\u003eFour-level PSO can be an effective treatment for severe rigid thoracic hyperkyphosis in osteoporotic patients. Although technically demanding and associated with potential complications, careful planning and staged correction can result in successful outcomes.\u003c/p\u003e\u003ch2\u003eLEVEL OF EVIDENCE\u003c/h2\u003e\u003cp\u003eIV (Case Report)\u003c/p\u003e","manuscriptTitle":"Four-Level Pedicle Subtraction Osteotomy for Severe Rigid Thoracic Hyperkyphosis: A Technical Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-08 10:25:56","doi":"10.21203/rs.3.rs-8172930/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-08T13:32:58+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-06T01:55:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"318492641820891099935448484986253388932","date":"2025-12-03T23:25:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"321785920613855586815338196460323060200","date":"2025-12-03T21:07:11+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-03T14:11:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-26T12:15:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-26T12:15:04+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Spine Journal","date":"2025-11-21T10:56:16+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"403dec9c-619c-4e9c-a7c4-9e665f8526a4","owner":[],"postedDate":"December 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-01-12T16:05:14+00:00","versionOfRecord":{"articleIdentity":"rs-8172930","link":"https://doi.org/10.1007/s00586-025-09734-8","journal":{"identity":"european-spine-journal","isVorOnly":false,"title":"European Spine Journal"},"publishedOn":"2026-01-08 15:57:29","publishedOnDateReadable":"January 8th, 2026"},"versionCreatedAt":"2025-12-08 10:25:56","video":"","vorDoi":"10.1007/s00586-025-09734-8","vorDoiUrl":"https://doi.org/10.1007/s00586-025-09734-8","workflowStages":[]},"version":"v1","identity":"rs-8172930","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8172930","identity":"rs-8172930","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}