Indian Spine Journal

CASE REPORT
Year
: 2019  |  Volume : 2  |  Issue : 2  |  Page : 152--157

Delayed postoperative spondylodiscitis in a case of diffuse idiopathic skeletal hyperostosis following surgical intervention for traumatic C7-T1 bifacetal dislocation


S Dilip Chand Raja, Ajoy Prasad Shetty, Rishi Mugesh Kanna, S Rajasekaran 
 Department of Spine Surgery, Ganga Hospital, Coimbatore, Tamil Nadu, India

Correspondence Address:
Dr. Ajoy Prasad Shetty
Department of Spine Surgery, Ganga Hospital, No. 313, Mettupalayam Road, Coimbatore, Tamil Nadu
India

Abstract

Postoperative spinal infections are on the rise owing to the ever-increasing number of spine surgeries. Spinal instrumentation is associated with an infection rate of 2%–8%. Both surgical and patient factors have been associated with infection. Delayed cases of postoperative infection are mostly related to patient-related factors and can be easily missed as they lack the classic clinical and systemic features. However, if left unidentified, progressive involvement of contiguous levels would result in collapse, instability, deformity, and instrumentation failure. A high index of suspicion is to be maintained, and higher imaging options such as magnetic resonance imaging and computed tomography should be used judiciously so as to diagnose infection at the earliest. We herein describe the background history, clinical features, imaging characteristics, and successful management of infective spondylodiscitis following instrumentation in a narrative manner. Relevant literature and management options have also been discussed.



How to cite this article:
Raja S D, Shetty AP, Kanna RM, Rajasekaran S. Delayed postoperative spondylodiscitis in a case of diffuse idiopathic skeletal hyperostosis following surgical intervention for traumatic C7-T1 bifacetal dislocation.Indian Spine J 2019;2:152-157


How to cite this URL:
Raja S D, Shetty AP, Kanna RM, Rajasekaran S. Delayed postoperative spondylodiscitis in a case of diffuse idiopathic skeletal hyperostosis following surgical intervention for traumatic C7-T1 bifacetal dislocation. Indian Spine J [serial online] 2019 [cited 2020 Apr 7 ];2:152-157
Available from: http://www.isjonline.com/text.asp?2019/2/2/152/263275


Full Text



 Introduction



Postoperative spinal infection is one of the most common complications following spine surgery and has devastating consequences on surgical outcomes.[1] The incidence of postoperative infection is highly varied and depends on a multitude of factors. Both patient-related and surgery-related risk factors have been discussed extensively.[2] The rate of infections following instrumentation is definitely higher. While diagnosis of surgical-site infections (SSI) is made early, deeper infections such as discitis and spondylitis are usually difficult to diagnose and treat.[3] Early diagnosis of such infections has favorable outcomes and requires a combination of clinical, radiological, and laboratory findings. The isolation of microorganisms from the infection site is essential for the eradication of infection.[4] In certain scenarios where there is significant collapse, deformity, instability, or incapacitating pain, instrumentation is warranted as it provides good immobilization to the spine during the healing process.

 Case Report



A 55-year-old known diabetic presented to the emergency department with cervicothoracic pain following fall on the previous day at home. Clinically he had severe restriction in the cervical range of movements, more so in the sagittal plane, with intact neurology. Because plain radiography was inadequate, computed tomography (CT) imaging [Figure 1] was done which revealed perched facets at C7–T1 level with translation. In addition, spondylotic changes with exuberant anterior marginal osteophytes suggestive of diffuse idiopathic skeletal hyperostosis (DISH) and segmental ossification of the posterior longitudinal ligament at C4–C5 level causing bony canal compromise were noted. His fasting blood sugar on the day following admission was 343 mg/dl and HbA1c level was 10.6%, suggestive of uncontrolled diabetes. In addition, high acetone levels (+++) found in urine and lactate levels of 2.7 mmol/L were suggestive of ketoacidosis. His albumin level of 4.3 g/dl was satisfactory. Diabetologist opinion was obtained, and insulin was administered along with oral hypoglycemic agents. Sugar levels were regularly monitored along with diet modification, and the dosages were titrated accordingly. Diabetic control was obtained in a gradual manner over a period of 5 days. On the day of surgery, his fasting sugar level was 136 mg/dl and he had no traces of acetone in urine. Lactate levels dropped to 1.7 mmol/L on the day of surgery. Closed reduction was attempted by skull traction using Crutchfield tongs with an initial weight of 4.5 kg followed by increase of 2.5 kg every day until 5 days. However, reduction could not be achieved. C7–T1 anterior cervical discectomy and fusion was performed. Considering the long lever arm across the dislocation due to DISH, and in view of the inherent instability of cervicothoracic junction, C6–T3 posterior instrumented stabilization was also performed in a single sitting. Postoperatively, the patient had hoarseness of voice and dysphagia. Indirect laryngoscopy done by otolaryngologist clearly showed right recurrent laryngeal nerve paralysis. Nasogastric intubation was performed, and after tolerating dilute fluids, formula feeding through catheter was continued for 4 weeks. Voice training was initiated in the immediate postoperative period. Glycopyrrolate was prescribed to control excessive oropharyngeal secretions to reduce micro-aspirations. He gradually started recovering over the next 2 weeks. By 6 weeks, he had a complete recovery and was started on normal feeds after nasogastric tube removal. He was on regular follow-up every 6 weeks and was completely asymptomatic until 5 months following surgery. He started experiencing diffuse pain over the nape of the neck, with referred pain over the bilateral shoulder blades, along with generalized fatigue. His plain radiographs showed certain increase in kyphosis at the cervicothoracic junction with pullout of distal screws, suggestive of loosening of hardware [Figure 2]. His HbA1c, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were 8.2%, 100 mm/h, and 41.9 mg/L respectively. Although there were no overt signs of infection the clinical, biochemical, and radiographic profile warranted further imaging with magnetic resonance imaging (MRI) and computed tomography (CT) [Figure 3] which was diagnostic of infective spondylodiscitis of T1–T3 levels. Blood, urine, and oral swab samples were sent for culture and sensitivity. Revision surgery was done and fixation levels were extended from C3 to T6 after thorough debridement, washout, and samples obtained were sent for tissue culture. Both oral and operative samples yielded heavy growth of Pseudomonas. Appropriate parenteral antibiotics were instituted and continued for 2 weeks and changed over to 6 weeks of oral antibiotics at discharge from hospital. The patient was followed up for 2 years. He is clinically normal and his follow-up imaging showed good resolution of infection. Currently, the patient has been restored to his preinjury functional status.{Figure 1}{Figure 2}{Figure 3}

 Discussion



The incidence of infection in instrumented spinal surgery is relatively higher when compared to simple procedures such as discectomy and decompression procedures.[5] Postoperative infection in spine surgery can be broadly classified into SSIs and deep vertebral or discal infections.[6] While SSIs have been discussed in detail in literature, there is relatively sparse data on deep infections. Further classification of deep infection based on chronology is as follows: early if within 20 weeks of the procedure, or delayed if they occur 20 weeks later. As is always said, “prevention is better than cure.” Assessing the clinical status of each patient and their comorbidities, identifying predisposing factors, achieving diabetic control and good nutrition, use of preoperative antibiotics, strict aseptic techniques, control of operating room traffic, judicious use of drains, being as minimally invasive as possible, and use of chemical disinfectants, followed by good postoperative care, individually play a vital role in avoiding the dreadful complication of iatrogenic infections.[7]

The greatest achievement in managing iatrogenic infections would be to achieve the earliest possible diagnosis. While SSIs often present with clear signs, deep infections of the spine, in exception to epidural abscess, pose a serious challenge because of their indolent nature and variegated presentation across individuals. Laboratory markers such as ESR, CRP, leukocyte count, and differential count as stand-alone investigations have not been useful and cannot be relied upon in identifying subclinical infections. Routine radiographs do not show signs of destruction in early stages and give only indirect evidence in the form of loosening of implants. MRI as a stand-alone investigation has been extremely useful in identifying early infections, even before what CT could demonstrate. However, CT helps in confirmation and gives further information on the extent of bony destruction, which helps in surgical planning. Thus, MRI with CT correlation is the most invaluable armamentarium available currently in managing postoperative spondylodiscitis.[8]

Whenever possible, attempts should be made in isolating organisms from the site of infection, either by percutaneous or open techniques.[9] In addition, blood, urine, and oropharyngeal swab samples are sent for culture, keeping in mind the hematogenous dissemination of microorganisms – the most common pathophysiology behind pyogenic spondylodiscitis. Medical treatment alone is restricted to superficial SSIs and in very early stages of infection with no evidence of loss of structural integrity and also in individuals not fit for surgery such as those who are in septicemia and/or are immune compromised.[9] Epidural abscess is a surgical emergency as it may cause fulminant neurological sequelae and warrants drainage at the earliest. The traditional thought of hardware removal fearing the formation of glycocalyx biofilms by the bacteria is now on a downfall.[10] Many reports have suggested that thorough debridement with good stability under appropriate antibiotic cover enables early rehabilitation, promotes faster healing, and aids in preventing deformity.[11] Premature removal of hardware would result in instability and would complicate the issue by increasing the hospital stay duration, morbidity, and the number of procedures performed.

The approach of surgery – anterior, posterior, or combined – depends on the site, extent, and the number of segments involved. The ideal way would be to tailor it as a single-staged final definitive procedure.[12] Anterior procedures are considered best, when there is substantial loss of bone resulting in kyphosis, with the aim of providing a solid structural support anteriorly. Removal of hardware can be considered, when structural support can be given in the form of tricortical grafts if two or lesser segments are involved. However, it becomes practically impossible in extensive infection and at the junctional regions of spine. Surgical experience does play a role in accessing the spine anteriorly, as there has been a steady decline in the number of anterior procedures performed globally. Successful management by posterior procedure alone with global reconstruction of anterior elements still holds good and has been well proven. Posterior approaches need minimal expertise and have less morbidity, especially in thoracic and thoracolumbar junction. Combined procedures would be the best if extensive clearance is required, in order to attain stability and prevent deformity, but hold the patients at a higher surgical stress. In summary, the three goals of surgical management are radical debridement, providing stability, and obtaining adequate samples for appropriate antibiotic treatment.

Rationale behind the surgical choice in the current scenario

With elevated ESR and CRP values and pullout of distal screws, the clinical suspicion of delayed infection was suspected, and further imaging by CT and MRI was done [Figure 3]. Both anterior and posterior structures were involved mainly from T1 to T3. Fortunately, not much of destruction was noted in anterior C7–T1 cage prosthesis level. Technically, removal of hardware alone would leave the spine highly unstable due to the following four reasons: (1) The indication for instrumentation in the index procedure was an unstable C7-T1 facetal dislocation rather than an elective spine surgery; (2) cervicothoracic junction has inherent instability; (3) long lever arms across the affected levels due to DISH will definitely cause an exponential rise in instability; and (4) endplate erosion would result in progressive kyphotic deformity. The early diagnosis of this delayed infection allowed us to intervene only posteriorly. T2 and T3 pedicle screws were removed, and instrumentation levels were extended to T6 [Figure 4]. Thorough debridement of posterior structures was done, and samples were sent for culture. The entire surgical site was washed with diluted povidone-iodine and hydrogen peroxide. Ten liters of saline wash was thoroughly given to reduce the bacterial load, and the wound was closed in layers over a deep surgical drain. A heavy growth of Pseudomonas was obtained from culture specimens and was treated with appropriate antibiotics. He was regularly followed up with serial biochemical, radiological, and clinical parameters.{Figure 4}

Final outcome

The predisposing factors for this patient who went on to delayed infection were uncontrolled diabetes mellitus, extensive duration of surgery due to the combined approach during the index procedure, postoperative decrement in nutritional status due to temporary Ryles tube feeding, and recurrent microspiration of oropharyngeal secretions over a period of 6 weeks. Postoperatively, there was a further rise in ESR and CRP as expected due to surgical intervention. The serial ESR values at admission, immediate postoperative period, and 1, 2, 3, 6, and 12 months were 100, 110, 60, 20, 12, 9, and 6 mm/h, respectively. Similarly, CRP values at admission, immediate postoperative period, and 1, 2, 3, and 6 months were 41.9, 112, 64, 12.2, 7.5, and 2.2 mg/l, respectively. Throughout the follow-up, he had shown good improvement clinically and remained neurologically intact. Radiological investigation was done serially on alternative follow-ups with satisfactory healing.

 Summary



Diagnosis in delayed infection after spinal instrumentation is a challenge, due to its torpid nature of presentation. The surgeon needs to be aware of its existence and maintain a high index of suspicion, especially in the immune-compromised and in patients who are prone to surgical stress. No single laboratory value is diagnostic, henceforth requiring corroborative evidence in establishing diagnosis. MRI with CT correlation comes to the rescue of the surgeon in such dubious scenarios.[13] Owing to the rarity of this entity of delayed infection, there is a huge lacuna in literature on its appropriate management. Pseudomonas aeruginosa is an uncommon cause of pyogenic spondylodiscitis. It is an opportunistic pathogen and is the most common cause of nosocomial infections, isolated extensively from patients who have had more than 1 week of hospital stay. Pseudomonas thrives well on moist surfaces such as urinary and nasogastric catheters and has the potential to extensively colonize and form enduring biofilms resulting in resistant postoperative implant-related infections. The ideal management in such a situation has always been debated. However, there is increasing evidence on the safety and efficacy of instrumentation even in active infection. Recently, emphasis is being laid on providing adequate stability following debridement, which promotes a rapid healing and fusion. In addition, early mobilization helps in reducing hospital stay and recumbence, indirectly reducing bacterial load.

 Conclusion



Despite all possible measures taken, there is a constant prevalence of postoperative spondylodiscitis worldwide and remains inevitable. Diagnosis in delayed infection after spinal instrumentation is a challenge, due to its torpid nature of presentation. Surgeons need to be aware of its existence and maintain a high index of suspicion, especially in the immune-compromised and in patients who have predisposing risk factors for infection. No single laboratory value is diagnostic, henceforth requiring corroborative evidence in establishing diagnosis. MRI with CT correlation comes to the rescue of the surgeon in such dubious scenarios and helps in early diagnosis. Instrumentation is safe even during active infection as far as the surgeon follows the main principles of debriding completely, providing stable environment for healing and ensuring best possible control of predisposing factors of spondylodiscitis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgment

All authors contributed equally toward the preparation of manuscript.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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