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Esophageal perforation following pedicle screw placement for the treatment of upper thoracic spinal tuberculosis: a case report and review of the literature

Esophageal perforation following pedicle screw placement for the treatment of upper thoracic... Background: The technique of posterior pedicle screw fixation has already been widely applied in the treatment of upper thoracic spinal tuberculosis. However, lesions of tuberculosis directly invade the vertebrae and surrounding soft tissues, which increases the risk of esophageal perforation induced by the posterior pedicle screw placement. Herein, we report the first case of esophageal perforation following pedicle screw placement in the upper thoracic spinal tuberculosis, and describe the underlying causes, as well as the treatment and prognosis. Case presentation: A 48-year-old female patient with upper thoracic spinal tuberculosis presented sputum-like secretions from the wound after she was treated with one-stage operation through the posterolateral approach. Endoscopy was immediately conducted, which confirmed that the patient complicated with postoperative esophageal perforation caused by screws. CT scan showed that the right screw perforated the anterior cortex of the vertebrae and the esophagus at the T4 level. Fortunately, mediastinal infection was not observed. The T4 screw was removed, Vacuum Sealing Drainage (VSD) was performed, and jejunum catheterization was used for enteral nutrition. After continuous treatment with sensitive antibiotics for 2.5 months and 5 times of VSD aspiration, the infected wound recovered gradually. With 18-month follow-up, the esophagus healed well, without symptoms of dysphagia and stomach discomfort, and CT scan showed that T2–4 had complete osseous fusion without sequestrum. Conclusion: Tuberculosis increases the risk of postoperative esophageal perforation in a certain degree for patients with upper thoracic tuberculosis. The damages to esophagus during the operation should be prevented. The screws with the length no more than 30 mm should be selected. Moreover, close monitoring after operation should be conducted to help the early identification, diagnosis and treatment, which could help preventing the adverse effects induced by the delayed diagnosis and treatment of esophageal perforation. Keywords: Upper thoracic spinal tuberculosis, Esophageal perforation, Esophageal fistula, Pedicle screw, Infection * Correspondence: wangbiaowb1987@126.com Department of Spine Surgery, Honghui Hospital, Xi’an Jiaotong University College of Medicine, No. 76 Nanguo Road, Xi’an 710054, Shaanxi, China Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 2 of 6 Background Spinal tuberculosis is the most common form of extra- pulmonary tuberculosis, accounting for approximately 1 to 3% of all tuberculosis cases, and 50% of musculoskel- etal infections [1, 2]. Although relatively rare in clinical practices, upper thoracic tuberculosis could induce se- vere damages. Patients with upper thoracic spinal tuber- culosis are generally accompanied with the destruction of vertebral body and intervertebral disc, formation of paravertebral abscess, and neurological impairments [3]. Among the surgical treatments of upper thoracic tuber- culosis, the posterolateral approach with pedicle screw fixation could achieve better correction of kyphosis and reconstruction of spinal stability, and thus has been more and more applied in recent years [4]. However, the complications of nerves, blood vessels, and vital organs caused by the pedicle screws have also attracted increas- ing attentions [5–7]. Soft tissues such as aorta, esophagus and lung are adja- cent to thoracic vertebrae, and the narrowness and incon- sistent shapes of the pedicles could also increase the challenges of posterior pedicle screw placement in upper thoracic spine [8, 9]. In addition, lesions of tuberculosis directly invade the vertebral body and surrounding soft tissues, which further increases the risks of vascular, spinal cord, and esophageal complications induced by posterior pedicle screw placement in upper thoracic spine. Fig. 1 T1 (a) and T2 (b) sequences of MRI showed T3 / 4 vertebral Various studies have already reported the neurological infectious disease with spinal cord compression, and axial images (c-f) and vascular complications related to pedicle screw showed bone defects in the anterior part of T3 and T4 vertebrae, placement in upper thoracic spine [6, 10–12]. However, tuberculosis foci were located around the oesophagus and pushed the the related complications in esophagus, an important oesophagus to the right side (the red arrow indicates the location of structure close to upper thoracic spine, are very rare, the lesion) and thus only very few cases have been reported. In this case report, we described esophageal perforation caused by pedicle screw in a patient of upper thoracic spinal tu- was then treated with enhanced tetrad anti-tuberculosis berculosis during the treatment. strategy (including isoniazid, rifampicin, pyrazinamide, and streptomycin) for 2 weeks, after which the ESR re- Case presentation duced to 42 mm/h and CRP reduced to 17 mg/L. Then A 48-year-old female patient was admitted to the hos- the one-stage operation through the posterolateral ap- pital due to back pain with unknown causes for over 20 proach was conducted. In brief, the focus debridement days, which could not be alleviated by nonsteroidal anti- through intertransverse articulation at the left rib, spinal inflammatory drugs (NSAIDs). MRI scan showed abnor- decompression, and ilium grafting were conducted. The mal signals at the third and fourth thoracic vertebral two ends of the lesion were fixed by two groups of ped- bodies and the T3/4 intervertebral disc, as well as infec- icle screws to restore the stability of upper thoracic spine tious lesions and formation of paravertebral abscess and correct the kyphosis. Few tissues of the lesions were (Fig. 1). Blood routine examination of the patient obtained during the operation for pathological examina- showed no abnormality, of which the erythrocyte sedi- tions, which showed caseous necrosis and tuberculosis mentation rate (ESR) was 98 mm/h, C-reactive protein infection. (CRP) was 75 mg/L, T-STOP.TB test showed high posi- After surgery, the patient was in persistent low-grade tivity. According to international standard revised by fever, and the white blood cell count, ESR, and CRP American Spinal Cord Injury Association (ASIA), the were slightly increased. Such changes were initially con- patient’s neurological function was grade D. Therefore, sidered to be the transient manifestations after opera- the patient was diagnosed upper thoracic spinal tubercu- tions of infectious diseases. However, sputum-like losis accompanied with spinal cord injury. The patient secretions were found during the dressing on the Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 3 of 6 postoperative Day 7, and the secretions containing small bubbles were found when pressing the wound. Based on our experience of treating esophageal injuries after an- terior cervical surgery, the tracheal or esophageal dam- ages were highly suspected, due to the fact that the bubbles could not be found in regular wound infections (except for the infection of aerobacter aerogenes). Fiberoptic bronchoscopy was immediately conducted, which showed that the airway of the patient was intact. Endoscopy of the upper gastrointestinal tract showed a bulge at 22 cm to the incisor, with a black hemispheric lustrous foreign matter at the center, which was sur- rounded by esophageal mucosa (Fig. 2). Endoscopy con- firmed that the patient was with postoperative esophageal perforation caused by screw. CT scan showed that the right screw perforated the anterior cortex of the vertebral body and the esophagus at the T4 level (Fig. 3). However, fortunately, no mediastinal infection was observed in the CT scan. After preoperative preparation, emergent posterior wound incision and rinsing was conducted. The T4 screw was removed, Vacuum Sealing Drainage (VSD) was performed, and jejunum catheterization was used for enteral nutrition. The patient was transferred to the intensive care unit (ICU) after the operation. The vital signs of the patient were stable on the day after oper- ation. After consulting with the physicians or surgeons from the departments of Gastroenterology, ICU, Thor- acic Surgery, and Spinal Surgery, the patient was trans- ferred back to our department 2 days later, while symptomatic and supportive treatment, including enteral Fig. 3 CT examination showed that the right screw of T4 vertebra was nutrition, anti-infection, infusion of human serum albu- too long, penetrated the anterior edge of vertebra and occupied the min, VSD, and continuously enhanced anti-tuberculosis anatomical position of oesophagus (red arrow), sagittal cuts along with were conducted. Endoscopy at 1 month later showed direction of the screws were showed in a-b and axial cuts at all levels were showed in c-f that the perforation of esophagus was completely healed, while the lumen dimeter of the esophagus was about 50% lower than that of normal esophagus. However, for- tunately, the patient had no symptoms of dysphagia or pain when swallowing, and thus no esophageal dilation was performed. The patient’s wound was with infection when the esophageal perforation was discovered. Bacter- ial culture showed that the infection was caused by Escherichia coli. After continuous treatment with sensi- tive antibiotics for 2.5 months and 5 times of VSD vacuum aspiration, the infected wound recovered gradually. After treated with the enhanced tetrad anti-tuberculosis strategy for 3 months, the patient was further treated with isoniazid, rifampicin, and pyrazinamide for 15 months for anti-tuberculosis. In addition, imaging and blood exami- nations were also conducted for the patient every 3 Fig. 2 Endoscopy showed oesophageal perforation caused by months. The re-examination at 18 months after operation pedicle screw showed tuberculosis clinical manifestations of the patient Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 4 of 6 of the too-long screw which was placed in the T3 seg- ment. Fortunately, the damage was detected early and endoscopy showed no sign of esophageal perforation. It was apparent that the esophageal perforation and dam- ages following posterior pedicle screw placement in upper thoracic spine in all reported cases were caused by the too long screws. Kwan et al. [15] used CT scan to examine 2020 pedicle screws, and found that the rate of perforating anterior cortex of vertebral body was 6.4%. Belmont et al. [16] assessed the placements of 279 pedicle screws in thor- acic spine, of which the postoperative CT scan showed that the mean length of perforating anterior cortex of vertebral body was 1.7 mm (1–4 mm) in 6% screws. The highest rate of perforating anterior cortex of vertebrae was in the T1-T4 vertebral bodies, which was in agree- ment with the findings of this case report that the T4 pedicle screw perforated the esophagus. In contrast to the upper thoracic spine, the too-long screw could also potentially perforate the right azygos vein, parietal pleura, left thoracic aorta, and esophagus [13]. Sariyil- maz et al. [5] suggested that screws with the length of > 35 mm should not be used in upper thoracic spine. Di Silvestre et al. [11] were even more careful, as they sug- gested that the length of the screws should not be longer than 25–30 mm in upper thoracic spine. In this case, the length of the screw that perforated the esophagus was 35 mm. We suggest that for treating upper thoracic spinal tuberculosis involving the destruction of vertebral bodies and surrounding soft tissues, screws with the length of ≤30 mm should be selected as possible. Fig. 4 18 months after operation, CT examination showed that T2–4 Using preoperative CT scan to predict the length had complete osseous fusion without dead bone existed from the insertion site to the anterior cortex of verte- bral body could possibly prevent such complication. disappeared, 3 continuous ESR and CRP examinations Still, preoperative planning could not completely elim- showed normal results, CT scan showed the union of inate the risk of screw complications, as the screw bone graft, and the upper thoracic spinal abscess disap- placement during the operation may not be as sched- peared, while no sequestrum was found (Fig. 4). These uled due to the deviation of the site and angle of the findings demonstrated that the upper thoracic spinal tu- insertion. It has been demonstrated that intraoperative berculosis met the criteria of clinical healing. imaging could reduce the pedicle screw-related com- plications [12]. However, it is difficult to display the Discussion and conclusion anterior margin of the upper thoracic spinal vertebral Screws were too long should be the primary cause of se- body by X-ray imaging in prone position [14]. A vere esophageal perforation in this case. Previously, Sar- meta-analysis investigated the safety profiles in 7533 iyilmaz et al. [5] and Marouby et al. [13] independently pedicle screws, which showed that the accuracy rate reported one scoliosis case with delayed esophageal per- of intraoperative CT and 2-dimensional X-ray were foration following the screw placement in T4 segment 90 and 85%, respectively. The difference is even (one at 3 years after operation, while the other at 10 higher in the upper thoracic spine [17]. Therefore, we years after operation). The esophageal perforations in suggest that for pedicle screw placement for upper both cases were caused by the long-term friction of thoracic spinal tuberculosis, preoperative CT scan esophagus due to the too-long screw, which perforated should be conducted to accurately measure the ana- the anterior cortex of vertebrae and contacted with the tomical parameters, and intraoperative CT navigation esophagus. In another case reported by O’Brien et al. should also be adopted to reduce the risk of compli- [14], the esophagus was damaged due to the oppression cations caused by the screws. Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 5 of 6 In recent years, robot techniques have been introduced enteral nutrition by jejunum catheterization was con- to the field of spinal surgery [18]. The accuracy rate of ducted for the patient for 1 month, and the esophageal robot-assisted pedicle screw placement was over 98%, perforation healed completely, which demonstrated the which could evidently reduce the incidence of complica- validity of the principle. The prognosis of esophageal tions [19–21]. Therefore, robot-assisting techniques perforation is mainly dependent on the presence of me- could also be used to reduce the risk of screw-related diastinal infection and its treatment effectiveness [25]. complications. Once combined with mediastinal infection, the mortality Upper thoracic spinal tuberculosis is a chronic inflam- of patient increases dramatically. Fortunately, the matory disease, in which the characteristics of the tuber- esophageal perforation detected in our patient was in culous lesions could also increase the risk of esophageal time (On the Day 7 after operation), and no mediastinal damages caused by pedicle screw placement. Cardoso infection occurred. The delayed diagnosis of perforation et al. [22] conducted T1-T4 CT scan for 20 patients, and could lead to irreversible outcomes and even endanger found that esophagus was with the highest risk of noso- the life of patient. comial damages regardless of the vertebral body level. In summary, for patients with upper thoracic spinal The mean distance from the tip of left screws to esopha- tuberculosis, the direct invasion of esophageal wall by gus was lower than that of the right screws, while the T2 tuberculous lesions and chronic oppression of esophagus vertebrae had the highest risk. In the present case, how- by paravertebral abscess could lead to ischemic necrosis ever, the right T4 screw perforated the anterior cortex of and thinning of esophageal wall, and the destruction of vertebrae and caused esophageal perforation. It could anterior cortex of vertebral body, all of which increase not only be associated with the fact that the right screw the risk of esophageal perforation. It is necessary to care- at T4 level was too long, but also that the tuberculous fully evaluate the preoperative imaging data and clarify lesions invaded the esophagus and reduced the elasticity the risky anatomic structures. In addition, the distance and increased the fragility of the tissues, which made the from the screw insertion site to anterior cortex of verte- esophagus tend to be damaged easier. In addition, the le- bral body should also be measured, and screws with the sions also changed the anatomical relationship between length no more than 30 mm should be selected. Naviga- esophagus and surrounding tissues, and the paraverteb- tion or robot-assisted techniques could also be adopted ral abscess pushed the esophagus to the right side, which if possible, which could prevent the esophageal damages further increased the risk of esophageal perforation by caused by the inserted screws. For patients with the pedicle screw. symptoms and signs highly suggesting esophageal per- This case report first reported the esophageal perfor- foration, early diagnosis and early treatment should be ation following posterior pedicle screw placement for conducted as early as possible to prevent devastating upper thoracic spinal tuberculosis. This complication is outcomes such as mediastinal infection. extremely rare, which could directly affect the lives of Abbreviations patients, and the mortality rate is as high as 20% [23]. CT: Computed tomography; VSD: Vacuum sealing drainage; T: Thoracic Both the two cases reported in previous studies were de- vertebra; T-STOP.TB: T cell enzyme-linked immunospot assay for tuberculosis; NSAIDs: Nonsteroidal anti-inflammatory drugs; MRI: Magnetic resonance layed perforation, and the posterior wound had already imaging; ESR: Erythrocyte sedimentation rate; CRP: C-reactive protein; completely healed, thus the treatment was relatively eas- ASIA: American spinal injury association; ICU: Intensive care unit ier. The case reported by Marouby et al. [13] achieved a Acknowledgements good outcome even without removing the screw. While We are thankful for the support of the nursing staffs from the Department of in this case, the spinal tuberculosis patient was accom- Spine Surgery, Xi’an Jiaotong University College of Medicine, Honghui panied with esophageal perforation and wound infection, Hospital. and thus the treatment was relatively tricky. In addition Authors’ contributions to enhanced tetrad anti-tuberculosis treatment, we also BW and DH conceived the original ideas of this manuscript. LQ, XH, and YW treated the wound infection and esophageal perforation participated in the surgical and medical treatment. YW and YM executed the fellow-up examination and materials collection. YW and BW analyzed the separately. The wound improved after surgical cleaning, examination results, analyzed the data, prepared the Figs and prepared the rinsing, drainage, and VSD vacuum aspiration. In manuscript. All authors have read and approved the manuscript. principle, because of the limited injury of esophageal Funding wall in esophageal perforation caused by screws alone, if This work was supported by the Medical Research Project of Xi’an Science there were no systemic infection symptoms after remov- and Technology Bureau (201805096YX4SF30–4). Fundings include the cost of ing the screw, appropriate treatment and nutritional collecting the fellow-up data and publication fee. support including careful observation, forbidding oral Availability of data and materials food intake, intravenous injection of broad-spectrum an- All relevant data was presented within the manuscript and the datasets used tibiotics, and application of proton-pump inhibitor and/or analyzed during the current study are available from the should be sufficient for the treatment [24]. In this case, corresponding author on reasonable request. Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 6 of 6 Ethics approval and consent to participate screws using computed tomography assessment. Spine (Phila Pa 1976). Not applicable. 2017;42(5):326–35. 16. Belmont PJ Jr, Klemme WR, Dhawan A, Polly DW Jr. In vivo accuracy of thoracic pedicle screws. Spine (Phila Pa 1976). 2001;26(21):2340–6. Consent for publication 17. Tian NF, Xu HZ. Image-guided pedicle screw insertion accuracy: a meta- The authors have obtained the patient’s written informed consent of his analysis. Int Orthop. 2009;33(4):895–903. personal clinical data and all images in this study for print and electronic 18. Chen AF, Kazarian GS, Jessop GW, Makhdom A. Robotic Technology in publication. Orthopaedic Surgery. J Bone Joint Surg Am. 2018;100(22):1984–92. 19. Zhang Q, Han XG, Xu YF, Fan MX, Zhao JW, Liu YJ, He D, Tian W. Robotic navigation during spine surgery. Expert Rev Med Devices. 2020;17(1):27–32. Competing interests 20. Lonjon N, Chan-Seng E, Costalat V, Bonnafoux B, Vassal M, Boetto J. Robot- The authors have no competing interests. assisted spine surgery: feasibility study through a prospective case-matched analysis. Eur Spine J. 2016;25(3):947–55. Author details 21. Han X, Tian W, Liu Y, Liu B, He D, Sun Y, Han X, Fan M, Zhao J, Xu Y, Zhang Department of Spine Surgery, Honghui Hospital, Xi’an Jiaotong University Q. Safety and accuracy of robot-assisted versus fluoroscopy-assisted pedicle College of Medicine, No. 76 Nanguo Road, Xi’an 710054, Shaanxi, China. screw insertion in thoracolumbar spinal surgery: a prospective randomized Xi’an Medical University, No. 74 Hanguang North Road, Xi’an 710054, controlled trial. J Neurosurg Spine. 2019:1–8. Shaanxi, China. 22. Cardoso MJ, Helgeson MD, Paik H, Dmitriev AE, Lehman RA Jr, Rosner MK. Structures at risk from pedicle screws in the proximal thoracic spine: Received: 17 April 2020 Accepted: 10 November 2020 computed tomography evaluation. Spine J. 2010;10(10):905–9. 23. Brinster CJ, Singhal S, Lee L, Marshall MB, Kaiser LR, Kucharczuk JC. Evolving options in the management of esophageal perforation. Ann Thorac Surg. References 2004;77(4):1475–83. 1. Wang B, Kong L, Zhu Z, Gao W, Guo H, Wang X, Li H, Zhao Q, Zhang H, 24. Abbas G, Schuchert MJ, Pettiford BL, Pennathur A, Landreneau J, Hao D. Recurrent complex spinal tuberculosis accompanied by sinus tract Landreneau J, Luketich JD, Landreneau RJ. Contemporaneous management formation: causes of recurrence and clinical treatments. Sci Rep. 2018;8(1): of esophageal perforation. Surgery. 2009;146(4):749–56. 25. Søreide JA, Viste A. Esophageal perforation: diagnostic work-up and clinical 2. Wang B, Shang R, Yang T, Zhang H, Hu H, Hu W, Hao D. Evaluation of decision-making in the first 24 hours. Scand J Trauma Resusc Emerg Med. clinical outcomes of one-stage anterior and posterior surgical treatment for 2011;19:66. atlantoaxial tuberculosis complicated with neurological damage. BMC Musculoskelet Disord. 2019;20(1):148. 3. Zeng H, Zhang Y, Shen X, Luo C, Xu Z, Liu Z, Liu X, Wang X. Staged Publisher’sNote treatment of thoracic and lumbar spinal tuberculosis with flow injection Springer Nature remains neutral with regard to jurisdictional claims in abscess. Int J Clin Exp Med. 2015;8(10):18383–90. published maps and institutional affiliations. 4. Srivastava SK, Aggarwal RA, Bhosale SK, Roy K, Nemade PS. The versatile approach: a novel single incision combined with anterior and posterior approaches for decompression and instrumented fusion to treat tuberculosis of the thoracic spine. Asian Spine J. 2017;11(2):294–304. 5. Sariyilmaz K, Ozkunt O, Sungur M, Dikici F, Domanic U. Esophageal perforation caused by a posterior pedicle screw: a case report. J Pediatr Orthop. 2017;37(2):98–101. 6. Hicks JM, Singla A, Shen FH, Arlet V. Complications of pedicle screw fixation in scoliosis surgery: a systematic review. Spine (Phila Pa 1976). 2010;35(11): E465–70. 7. Samdani AF, Ranade A, Sciubba DM, Cahill PJ, Antonacci MD, Clements DH, Betz RR. Accuracy of free-hand placement of thoracic pedicle screws in adolescent idiopathic scoliosis: how much of a difference does surgeon experience make? Eur Spine J. 2010;19(1):91–5. 8. Zeiller SC, Lee J, Lim M. Posterior thoracic segmental pedicle screw instrumentation: evolving methods of safe and effective placement. Neurol India. 2005;53(4):458–65. 9. Vaccaro AR, Rizzolo SJ, Balderston RA, Allardyce TJ, Garfin SR, Dolinskas C, An HS. Placement of pedicle screws in the thoracic spine. Part II: An anatomical and radiographic assessment. J Bone Joint Surg Am. 1995;77(8): 1200–6. 10. Alanay A, Cil A, Acaroglu E, Caglar O, Akgun R, Marangoz S, Yazici M, Surat A. Late spinal cord compression caused by pulled-out thoracic pedicle screws: a case report. Spine (Phila Pa 1976). 2003;28(24):E506–10. 11. Di Silvestre M, Parisini P, Lolli F, Bakaloudis G. Complications of thoracic pedicle screws in scoliosis treatment. Spine (Phila Pa 1976). 2007;32(15): 1655–61. 12. Martin S, Lindsay R, Baker RC. Simultaneous endovascular repair of a thoracic aortic injury during posterior pedicle screw removal: a case report. Ann Vasc Surg. 2018;48:252.e1–4. 13. Marouby S, Jeandel C, M'Sabah DL, Delpont M, Cottalorda J. Esophageal perforation caused by a thoracic pedicle screw. Eur Spine J. 2018. https:// doi.org/10.1007/s00586-018-5611-3. 14. O'Brien JR, Krushinski E, Zarro CM, Sciadini M, Gelb D, Ludwig S. Esophageal injury from thoracic pedicle screw placement in a polytrauma patient: a case report and literature review. J Orthop Trauma. 2006;20(6):431–4. 15. Kwan MK, Chiu CK, Gani SM, Wei CC. Accuracy and safety of pedicle screw placement in adolescent idiopathic scoliosis patients: a review of 2020 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png BMC Musculoskeletal Disorders Springer Journals

Esophageal perforation following pedicle screw placement for the treatment of upper thoracic spinal tuberculosis: a case report and review of the literature

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Abstract

Background: The technique of posterior pedicle screw fixation has already been widely applied in the treatment of upper thoracic spinal tuberculosis. However, lesions of tuberculosis directly invade the vertebrae and surrounding soft tissues, which increases the risk of esophageal perforation induced by the posterior pedicle screw placement. Herein, we report the first case of esophageal perforation following pedicle screw placement in the upper thoracic spinal tuberculosis, and describe the underlying causes, as well as the treatment and prognosis. Case presentation: A 48-year-old female patient with upper thoracic spinal tuberculosis presented sputum-like secretions from the wound after she was treated with one-stage operation through the posterolateral approach. Endoscopy was immediately conducted, which confirmed that the patient complicated with postoperative esophageal perforation caused by screws. CT scan showed that the right screw perforated the anterior cortex of the vertebrae and the esophagus at the T4 level. Fortunately, mediastinal infection was not observed. The T4 screw was removed, Vacuum Sealing Drainage (VSD) was performed, and jejunum catheterization was used for enteral nutrition. After continuous treatment with sensitive antibiotics for 2.5 months and 5 times of VSD aspiration, the infected wound recovered gradually. With 18-month follow-up, the esophagus healed well, without symptoms of dysphagia and stomach discomfort, and CT scan showed that T2–4 had complete osseous fusion without sequestrum. Conclusion: Tuberculosis increases the risk of postoperative esophageal perforation in a certain degree for patients with upper thoracic tuberculosis. The damages to esophagus during the operation should be prevented. The screws with the length no more than 30 mm should be selected. Moreover, close monitoring after operation should be conducted to help the early identification, diagnosis and treatment, which could help preventing the adverse effects induced by the delayed diagnosis and treatment of esophageal perforation. Keywords: Upper thoracic spinal tuberculosis, Esophageal perforation, Esophageal fistula, Pedicle screw, Infection * Correspondence: wangbiaowb1987@126.com Department of Spine Surgery, Honghui Hospital, Xi’an Jiaotong University College of Medicine, No. 76 Nanguo Road, Xi’an 710054, Shaanxi, China Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 2 of 6 Background Spinal tuberculosis is the most common form of extra- pulmonary tuberculosis, accounting for approximately 1 to 3% of all tuberculosis cases, and 50% of musculoskel- etal infections [1, 2]. Although relatively rare in clinical practices, upper thoracic tuberculosis could induce se- vere damages. Patients with upper thoracic spinal tuber- culosis are generally accompanied with the destruction of vertebral body and intervertebral disc, formation of paravertebral abscess, and neurological impairments [3]. Among the surgical treatments of upper thoracic tuber- culosis, the posterolateral approach with pedicle screw fixation could achieve better correction of kyphosis and reconstruction of spinal stability, and thus has been more and more applied in recent years [4]. However, the complications of nerves, blood vessels, and vital organs caused by the pedicle screws have also attracted increas- ing attentions [5–7]. Soft tissues such as aorta, esophagus and lung are adja- cent to thoracic vertebrae, and the narrowness and incon- sistent shapes of the pedicles could also increase the challenges of posterior pedicle screw placement in upper thoracic spine [8, 9]. In addition, lesions of tuberculosis directly invade the vertebral body and surrounding soft tissues, which further increases the risks of vascular, spinal cord, and esophageal complications induced by posterior pedicle screw placement in upper thoracic spine. Fig. 1 T1 (a) and T2 (b) sequences of MRI showed T3 / 4 vertebral Various studies have already reported the neurological infectious disease with spinal cord compression, and axial images (c-f) and vascular complications related to pedicle screw showed bone defects in the anterior part of T3 and T4 vertebrae, placement in upper thoracic spine [6, 10–12]. However, tuberculosis foci were located around the oesophagus and pushed the the related complications in esophagus, an important oesophagus to the right side (the red arrow indicates the location of structure close to upper thoracic spine, are very rare, the lesion) and thus only very few cases have been reported. In this case report, we described esophageal perforation caused by pedicle screw in a patient of upper thoracic spinal tu- was then treated with enhanced tetrad anti-tuberculosis berculosis during the treatment. strategy (including isoniazid, rifampicin, pyrazinamide, and streptomycin) for 2 weeks, after which the ESR re- Case presentation duced to 42 mm/h and CRP reduced to 17 mg/L. Then A 48-year-old female patient was admitted to the hos- the one-stage operation through the posterolateral ap- pital due to back pain with unknown causes for over 20 proach was conducted. In brief, the focus debridement days, which could not be alleviated by nonsteroidal anti- through intertransverse articulation at the left rib, spinal inflammatory drugs (NSAIDs). MRI scan showed abnor- decompression, and ilium grafting were conducted. The mal signals at the third and fourth thoracic vertebral two ends of the lesion were fixed by two groups of ped- bodies and the T3/4 intervertebral disc, as well as infec- icle screws to restore the stability of upper thoracic spine tious lesions and formation of paravertebral abscess and correct the kyphosis. Few tissues of the lesions were (Fig. 1). Blood routine examination of the patient obtained during the operation for pathological examina- showed no abnormality, of which the erythrocyte sedi- tions, which showed caseous necrosis and tuberculosis mentation rate (ESR) was 98 mm/h, C-reactive protein infection. (CRP) was 75 mg/L, T-STOP.TB test showed high posi- After surgery, the patient was in persistent low-grade tivity. According to international standard revised by fever, and the white blood cell count, ESR, and CRP American Spinal Cord Injury Association (ASIA), the were slightly increased. Such changes were initially con- patient’s neurological function was grade D. Therefore, sidered to be the transient manifestations after opera- the patient was diagnosed upper thoracic spinal tubercu- tions of infectious diseases. However, sputum-like losis accompanied with spinal cord injury. The patient secretions were found during the dressing on the Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 3 of 6 postoperative Day 7, and the secretions containing small bubbles were found when pressing the wound. Based on our experience of treating esophageal injuries after an- terior cervical surgery, the tracheal or esophageal dam- ages were highly suspected, due to the fact that the bubbles could not be found in regular wound infections (except for the infection of aerobacter aerogenes). Fiberoptic bronchoscopy was immediately conducted, which showed that the airway of the patient was intact. Endoscopy of the upper gastrointestinal tract showed a bulge at 22 cm to the incisor, with a black hemispheric lustrous foreign matter at the center, which was sur- rounded by esophageal mucosa (Fig. 2). Endoscopy con- firmed that the patient was with postoperative esophageal perforation caused by screw. CT scan showed that the right screw perforated the anterior cortex of the vertebral body and the esophagus at the T4 level (Fig. 3). However, fortunately, no mediastinal infection was observed in the CT scan. After preoperative preparation, emergent posterior wound incision and rinsing was conducted. The T4 screw was removed, Vacuum Sealing Drainage (VSD) was performed, and jejunum catheterization was used for enteral nutrition. The patient was transferred to the intensive care unit (ICU) after the operation. The vital signs of the patient were stable on the day after oper- ation. After consulting with the physicians or surgeons from the departments of Gastroenterology, ICU, Thor- acic Surgery, and Spinal Surgery, the patient was trans- ferred back to our department 2 days later, while symptomatic and supportive treatment, including enteral Fig. 3 CT examination showed that the right screw of T4 vertebra was nutrition, anti-infection, infusion of human serum albu- too long, penetrated the anterior edge of vertebra and occupied the min, VSD, and continuously enhanced anti-tuberculosis anatomical position of oesophagus (red arrow), sagittal cuts along with were conducted. Endoscopy at 1 month later showed direction of the screws were showed in a-b and axial cuts at all levels were showed in c-f that the perforation of esophagus was completely healed, while the lumen dimeter of the esophagus was about 50% lower than that of normal esophagus. However, for- tunately, the patient had no symptoms of dysphagia or pain when swallowing, and thus no esophageal dilation was performed. The patient’s wound was with infection when the esophageal perforation was discovered. Bacter- ial culture showed that the infection was caused by Escherichia coli. After continuous treatment with sensi- tive antibiotics for 2.5 months and 5 times of VSD vacuum aspiration, the infected wound recovered gradually. After treated with the enhanced tetrad anti-tuberculosis strategy for 3 months, the patient was further treated with isoniazid, rifampicin, and pyrazinamide for 15 months for anti-tuberculosis. In addition, imaging and blood exami- nations were also conducted for the patient every 3 Fig. 2 Endoscopy showed oesophageal perforation caused by months. The re-examination at 18 months after operation pedicle screw showed tuberculosis clinical manifestations of the patient Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 4 of 6 of the too-long screw which was placed in the T3 seg- ment. Fortunately, the damage was detected early and endoscopy showed no sign of esophageal perforation. It was apparent that the esophageal perforation and dam- ages following posterior pedicle screw placement in upper thoracic spine in all reported cases were caused by the too long screws. Kwan et al. [15] used CT scan to examine 2020 pedicle screws, and found that the rate of perforating anterior cortex of vertebral body was 6.4%. Belmont et al. [16] assessed the placements of 279 pedicle screws in thor- acic spine, of which the postoperative CT scan showed that the mean length of perforating anterior cortex of vertebral body was 1.7 mm (1–4 mm) in 6% screws. The highest rate of perforating anterior cortex of vertebrae was in the T1-T4 vertebral bodies, which was in agree- ment with the findings of this case report that the T4 pedicle screw perforated the esophagus. In contrast to the upper thoracic spine, the too-long screw could also potentially perforate the right azygos vein, parietal pleura, left thoracic aorta, and esophagus [13]. Sariyil- maz et al. [5] suggested that screws with the length of > 35 mm should not be used in upper thoracic spine. Di Silvestre et al. [11] were even more careful, as they sug- gested that the length of the screws should not be longer than 25–30 mm in upper thoracic spine. In this case, the length of the screw that perforated the esophagus was 35 mm. We suggest that for treating upper thoracic spinal tuberculosis involving the destruction of vertebral bodies and surrounding soft tissues, screws with the length of ≤30 mm should be selected as possible. Fig. 4 18 months after operation, CT examination showed that T2–4 Using preoperative CT scan to predict the length had complete osseous fusion without dead bone existed from the insertion site to the anterior cortex of verte- bral body could possibly prevent such complication. disappeared, 3 continuous ESR and CRP examinations Still, preoperative planning could not completely elim- showed normal results, CT scan showed the union of inate the risk of screw complications, as the screw bone graft, and the upper thoracic spinal abscess disap- placement during the operation may not be as sched- peared, while no sequestrum was found (Fig. 4). These uled due to the deviation of the site and angle of the findings demonstrated that the upper thoracic spinal tu- insertion. It has been demonstrated that intraoperative berculosis met the criteria of clinical healing. imaging could reduce the pedicle screw-related com- plications [12]. However, it is difficult to display the Discussion and conclusion anterior margin of the upper thoracic spinal vertebral Screws were too long should be the primary cause of se- body by X-ray imaging in prone position [14]. A vere esophageal perforation in this case. Previously, Sar- meta-analysis investigated the safety profiles in 7533 iyilmaz et al. [5] and Marouby et al. [13] independently pedicle screws, which showed that the accuracy rate reported one scoliosis case with delayed esophageal per- of intraoperative CT and 2-dimensional X-ray were foration following the screw placement in T4 segment 90 and 85%, respectively. The difference is even (one at 3 years after operation, while the other at 10 higher in the upper thoracic spine [17]. Therefore, we years after operation). The esophageal perforations in suggest that for pedicle screw placement for upper both cases were caused by the long-term friction of thoracic spinal tuberculosis, preoperative CT scan esophagus due to the too-long screw, which perforated should be conducted to accurately measure the ana- the anterior cortex of vertebrae and contacted with the tomical parameters, and intraoperative CT navigation esophagus. In another case reported by O’Brien et al. should also be adopted to reduce the risk of compli- [14], the esophagus was damaged due to the oppression cations caused by the screws. Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 5 of 6 In recent years, robot techniques have been introduced enteral nutrition by jejunum catheterization was con- to the field of spinal surgery [18]. The accuracy rate of ducted for the patient for 1 month, and the esophageal robot-assisted pedicle screw placement was over 98%, perforation healed completely, which demonstrated the which could evidently reduce the incidence of complica- validity of the principle. The prognosis of esophageal tions [19–21]. Therefore, robot-assisting techniques perforation is mainly dependent on the presence of me- could also be used to reduce the risk of screw-related diastinal infection and its treatment effectiveness [25]. complications. Once combined with mediastinal infection, the mortality Upper thoracic spinal tuberculosis is a chronic inflam- of patient increases dramatically. Fortunately, the matory disease, in which the characteristics of the tuber- esophageal perforation detected in our patient was in culous lesions could also increase the risk of esophageal time (On the Day 7 after operation), and no mediastinal damages caused by pedicle screw placement. Cardoso infection occurred. The delayed diagnosis of perforation et al. [22] conducted T1-T4 CT scan for 20 patients, and could lead to irreversible outcomes and even endanger found that esophagus was with the highest risk of noso- the life of patient. comial damages regardless of the vertebral body level. In summary, for patients with upper thoracic spinal The mean distance from the tip of left screws to esopha- tuberculosis, the direct invasion of esophageal wall by gus was lower than that of the right screws, while the T2 tuberculous lesions and chronic oppression of esophagus vertebrae had the highest risk. In the present case, how- by paravertebral abscess could lead to ischemic necrosis ever, the right T4 screw perforated the anterior cortex of and thinning of esophageal wall, and the destruction of vertebrae and caused esophageal perforation. It could anterior cortex of vertebral body, all of which increase not only be associated with the fact that the right screw the risk of esophageal perforation. It is necessary to care- at T4 level was too long, but also that the tuberculous fully evaluate the preoperative imaging data and clarify lesions invaded the esophagus and reduced the elasticity the risky anatomic structures. In addition, the distance and increased the fragility of the tissues, which made the from the screw insertion site to anterior cortex of verte- esophagus tend to be damaged easier. In addition, the le- bral body should also be measured, and screws with the sions also changed the anatomical relationship between length no more than 30 mm should be selected. Naviga- esophagus and surrounding tissues, and the paraverteb- tion or robot-assisted techniques could also be adopted ral abscess pushed the esophagus to the right side, which if possible, which could prevent the esophageal damages further increased the risk of esophageal perforation by caused by the inserted screws. For patients with the pedicle screw. symptoms and signs highly suggesting esophageal per- This case report first reported the esophageal perfor- foration, early diagnosis and early treatment should be ation following posterior pedicle screw placement for conducted as early as possible to prevent devastating upper thoracic spinal tuberculosis. This complication is outcomes such as mediastinal infection. extremely rare, which could directly affect the lives of Abbreviations patients, and the mortality rate is as high as 20% [23]. CT: Computed tomography; VSD: Vacuum sealing drainage; T: Thoracic Both the two cases reported in previous studies were de- vertebra; T-STOP.TB: T cell enzyme-linked immunospot assay for tuberculosis; NSAIDs: Nonsteroidal anti-inflammatory drugs; MRI: Magnetic resonance layed perforation, and the posterior wound had already imaging; ESR: Erythrocyte sedimentation rate; CRP: C-reactive protein; completely healed, thus the treatment was relatively eas- ASIA: American spinal injury association; ICU: Intensive care unit ier. The case reported by Marouby et al. [13] achieved a Acknowledgements good outcome even without removing the screw. While We are thankful for the support of the nursing staffs from the Department of in this case, the spinal tuberculosis patient was accom- Spine Surgery, Xi’an Jiaotong University College of Medicine, Honghui panied with esophageal perforation and wound infection, Hospital. and thus the treatment was relatively tricky. In addition Authors’ contributions to enhanced tetrad anti-tuberculosis treatment, we also BW and DH conceived the original ideas of this manuscript. LQ, XH, and YW treated the wound infection and esophageal perforation participated in the surgical and medical treatment. YW and YM executed the fellow-up examination and materials collection. YW and BW analyzed the separately. The wound improved after surgical cleaning, examination results, analyzed the data, prepared the Figs and prepared the rinsing, drainage, and VSD vacuum aspiration. In manuscript. All authors have read and approved the manuscript. principle, because of the limited injury of esophageal Funding wall in esophageal perforation caused by screws alone, if This work was supported by the Medical Research Project of Xi’an Science there were no systemic infection symptoms after remov- and Technology Bureau (201805096YX4SF30–4). Fundings include the cost of ing the screw, appropriate treatment and nutritional collecting the fellow-up data and publication fee. support including careful observation, forbidding oral Availability of data and materials food intake, intravenous injection of broad-spectrum an- All relevant data was presented within the manuscript and the datasets used tibiotics, and application of proton-pump inhibitor and/or analyzed during the current study are available from the should be sufficient for the treatment [24]. In this case, corresponding author on reasonable request. Wang et al. BMC Musculoskeletal Disorders (2020) 21:756 Page 6 of 6 Ethics approval and consent to participate screws using computed tomography assessment. Spine (Phila Pa 1976). Not applicable. 2017;42(5):326–35. 16. Belmont PJ Jr, Klemme WR, Dhawan A, Polly DW Jr. In vivo accuracy of thoracic pedicle screws. Spine (Phila Pa 1976). 2001;26(21):2340–6. Consent for publication 17. Tian NF, Xu HZ. 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Published: Dec 1, 2020

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