|Year : 2021 | Volume
| Issue : 4 | Page : 29-34
Delayed Adjacent Segment Infection After Anterior Cervical Discectomy and Fusion
Uddanapalli Sreeramulu Srinivasan
Department of Neurosurgery, Sri Balaji Hospital, Chennai, Tamil Nadu, India
|Date of Submission||29-Jul-2020|
|Date of Acceptance||29-Jul-2020|
|Date of Web Publication||24-Dec-2021|
Uddanapalli Sreeramulu Srinivasan
3A Malavika Apartments, New No 70, 3rd Main Road, Gandhi Nagar, Adyar, Chennai - 600 020, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Adjacent level infection (ASI) is a rare but potentially serious complication of anterior cervical fusion. We report a case of spondylodiscitis occurring adjacent to level at which anterior cervical discectomy and fusion was performed. The objective is to describe a rare case of cervical ASI which occurred after an undetermined oesophageal injury which lead to a series of complications in the same patient as non-union of the bone graft followed by anterior migration of the bone graft, delayed occurrence of spondylodiscitis at the same level and ASI below that level due to Klebsiella Pneumoniae which was successfully managed.
Keywords: Adjacent segment discitis, anterior cervical discectomy and fusion, cervical adjacent segment infection, esophageal injury
|How to cite this article:|
Srinivasan US. Delayed Adjacent Segment Infection After Anterior Cervical Discectomy and Fusion. J Spinal Surg 2021;8:29-34
| Introduction|| |
Disc space infection is a rare disease and it can occur either spontaneously or following surgery., Clinical and imaging findings suggest the diagnosis of infection at the disc space. Magnetic resonance imaging (MRI) is the investigation of choice in view of its high sensitivity, specificity, and accuracy. The most common organism implicated in the pathogenesis of disc space infection are Staphylococcus aureus and Staphylococcus epidermidis.,, Pyogenic infection at the operated spinal segment is a well-known entity.,,, Adjacent segment infection (ASI) has been reported commonly at lumbar level after various lumbar spine surgeries.,,, It is very rare at cervical level and literature search shows only three cases.,, In this case report, we present a rare case of delayed occurrence of ASI at cervical level following Anterior microdiscectomy and fusion performed for a cervical disc prolapse.
| Case Report|| |
A 45-year-old male patient, driver by occupation presented with neck pain of 2 year's duration spreading to the interscapular region on both sides, which got aggravated after driving. He had restriction of neck movements on clinical examination without any other neurological deficit. His neck pain did not get relieved with conservative treatment for more than 2 years and indeed it worsened which led to his frequent absence of work. He is a diabetic for 5 years and his blood sugar values were under good control. His MRI showed a significant disc protrusion at C3–C4 level causing severe cord compression. Anteroposterior canal diameter at that level was only 6 mm. Hyperintense signal was noted within the spinal cord at that level in T2 images [Figure 1]. A standard anterior cervical discectomy and fusion (ACDF) using tricortical iliac crest autograft and anterior cervical plating (Synthes, Swiss) was performed using a right-handed approach. Anterior cervical plating was used even though single level discectomy with the intent of aiding him to return to work as a driver at the earliest period. Prophylactic intravenous antibiotic cefuroxime was administered 1 h before surgery and continued for 24 h in the postoperative period. Immediate postoperative period was uneventful. Initial postoperative X-ray of cervical spine showed good position of the bony graft and the implant. Hence, he was discharged.
Ten days following surgery, he developed mild fever, neck pain with difficulty in swallowing associated with swelling in front of the neck. His repeat X-ray of the cervical spine revealed the presence of gas shadow in front of C3–C4 vertebral bodies at the operated level suggestive of esophageal injury [Figure 2]. Esophageal Gastrograffin study done immediately confirmed the site of leak at the level of hypopharynx on the right side. Hematological investigations revealed an increase in white blood cells (WBC) count (10,790 cells) with predominant neutrophils, raised erythrocyte sedimentation rate (ESR) (60 mm/hour) all suggestive of ongoing infective process at the operative site.
The patient was immediately taken for reexploration. Anesthetist under vision introduced the nasogastric tube. Its position was confirmed using an image intensifier. Following this cervical wound exploration and drainage of abscess in the prevertebral space was performed. Pus was sent for culture and sensitivity. The anterior cervical plating at C3–C4 level was removed. Since the bone graft was well impacted it was decided not to remove the bone graft. Site of esophageal injury could not be located intraoperatively suggestive of very small tear in the hypopharynx. Hence, the exposed hypopharynx lateral wall was lined with an oxidized cellulose strip (Surgicel) at the end of procedure. Thorough irrigation with gentamicin mixed solution was given and wound closed with drainage. Following the above intervention, twice the neck wound was explored with a gap of 4 days between each reexploration and there was no abscess or collection and each time wound irrigation with gentamicin solution was given. Simultaneously, feeding jejunostomy was performed since it was decided to keep him nil per orally for 8 weeks to allow the esophageal injury to heal.
The culture specimen grew Klebsiella pneumoniae sensitive to most of the antibiotics. Hence, the patient was started with injection cefoperazone-sulbactam which was given for 2 weeks. He was periodically followed up clinically every week. Serial radiographs of the cervical spine even though initially showed good position of the bone graft [Figure 3], on follow-up showed anterior migration of the bone graft [Figure 4]. Computed tomography (CT) scan of cervical spine showed nonunion of graft at C3–C4 disc space with anterior migration of the bone graft [Figure 5]. Hence, he was readmitted and taken for reexploration and removal of the extruded bone graft at C3–C4 level. Postoperative period was uneventful. Reviewing the initial CT scan of cervical spine showed only extruded bone graft without any evidence of bony changes in the adjacent spine [Figure 5].
|Figure 3: X-ray cervical spine showing good position of bone graft at C3-C4 level|
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|Figure 4: X-ray cervical spine (Lateral) showing anterior migration of the bone graft at C3-C4|
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|Figure 5: Computed tomography cervical spine showing the extruded bone graft at C3-C4 level|
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He continued to have neck pain with intermittent spikes of fever despite being on antibiotics. Hence, 3 weeks after surgical removal of bone graft, MRI cervical spine with contrast [Figure 6] was done which showed irregular osteolytic area in the anteroinferior aspect of C4 vertebral body on the right side. The opposing end plates at C4–C5 appear irregular with reduced C4–C5 disc height. Abnormal hyperintense signal was observed in C4–C5 disc space and in C3–C4 disc space. Similar abnormal hyperintense signal was observed in the prevertebral space extending from the lower margin of C3 to the lower margin of C5 vertebral body. There was enhancement with contrast at the anteroinferior aspect of C4 vertebral body and posterior aspect of C4–C5 disc space. There was homogeneously enhancing lesion in the prevertebral space with enhancement of the C4–C5 disc space. Previously seen small hyperintense signal in T2 images was observed within the cervical spinal cord at C3–C4 level, but there was no cord compression. Thus, the MRI suggestive of discitis at C3–C4 level and the adjacent segment C4–C5 level which was not touched during surgery [Figure 6]. It was decided to continue parenteral antibiotic treatment with ciprofloxacin instead of cefoperazone-sulbactam for another 6 weeks and manage him conservatively with cervical collar and symptomatic treatment of fever. Feeding jejunostomy was retained. Follow-up CT cervical spine [Figure 7] performed 1 month later after treatment with antibiotic showed erosions of inferior half of C4 vertebral body and superior endplate of C5. Intervening disc was destroyed. Mild retrolisthesis of C4 over C5 compromising the spinal canal. Prevertebral collection from C3 to C7 levels was noted. These features were suggestive of infective spondylitis at C4–C5 with prevertebral collection. Since clinically patient neck pain subsided and he was afebrile without neurological deficit and his WBC count was 6080 with ESR 20 mm/hour and already he had been subjected to five surgeries over the cervical spine including the primary ACDF, it was decided to continue conservative management with parenteral antibiotic ciprofloxacin. Antibiotic was given parenterally for 8 weeks and then switched over to oral form which was given for another 8 weeks. The patient improved with treatment.
|Figure 6: Magnetic resonance imaging with contrast showing enhancement at C3-C4, C4-C5 disc spaces|
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|Figure 7: Computed tomography scan cervical spine showing erosion of C4 body|
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Repeat Gastrografin swallow performed a month later showed no evidence of contrast leak from pharynx or proximal esophagus [Figure 8]. There was free flow of contrast distally. The patient was observed for another 4 weeks. Gastrografin study was repeated at the end of 2 months and confirming that there was no contrast leak, he was started on oral feeds which he tolerated. Hence, feeding jejunostomy was closed and he was continued on oral feeds. His neck was externally immobilized using a hard cervical collar for 6 months. He was allowed to return back to his profession after 6 months from the initial surgery. The patient was periodically followed up for nearly 5 years and there was no dysphagia or neck swelling and no episodes of fever or deterioration in neurological status. He was able to return to his work as a driver. Serial radiographs of the cervical spine showed fusion of the C3–C4, C4–C5 disc spaces [Figure 9]. The patient occasionally on driving long distances of over 300 km used to have tolerable neck pain which was relieved with analgesics and cervical collar for 10 days. In the 5 years, he had 6 episodes of such neck pain which was treated symptomatically.
|Figure 9: X-ray showing fusion of the disc spaces at C3-C4, C4-C5 levels|
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| Discussion|| |
In the largest series of ASI of 23 cases among 1187 patients reported by Siam et al., they had one cervical case (4.3%). Further Medline search showed two more cases in cervical spine., Predominantly, ASI occurred in lumbar spine. In lumbar spine ASI, surgical approach is usually advocated with radical debridement, posterior stabilization, and reconstruction of anterior column using expandable titanium cages. This method of treatment is widely favored., Here, we report another rare case of cervical ASI which occurred a few weeks after ACDF.
Siam et al. proposed that ASI could have occurred because of hematogeneous infection route, since in their study eight patients (34.8%) had positive blood cultures within the follow-up time. Lange et al. suspected direct infection of adjacent segment by intraoperatively contaminated screws. Siam et al. suggest that direct contamination during surgery by faulty drilling or by cranially or caudally located screws may have a role in ASI which was also suggested by Kulkarni and Hee., Screw loosening as the cause for ASI has been proposed. They assumed that slowly progressively loosening of screws caused repeated microfracture in pedicles and endplates. In these microfracture areas, the bacteria settled and proliferated leading to ASI. In our case, we feel initial esophageal injury leading to prevertebral abscess could have led to delayed direct infection in the C4–C5 disc space which was not touched during the surgeries as no screw was implanted at C5 body but still the endplate was infected [Figure 6]. Infection at C3-C4 disc space could be attributed to direct infection since after drainage of abscess and removal of the titanium cervical implant still discitis occurred leading to nonunion of bone graft and anterior slippage of the graft leading to removal of the bone graft. This could have occurred due to migration of the organism through the preexisting drill holes made in the body of C3–C4 bodies after removal of the cervical plate and screws. Various complications after esophageal injury have been reported but ASI has not been reported.
We also looked into the timeline of events of each complication. It was observed that following esophageal injury which could have taken place during the initial surgery, within a week retropharyngeal abscess is formed. After confirming the leak using Gastrografin study and initiating only feeds, initially through the nasogastric tube followed by feeding jejunostomy, within 4 weeks small esophageal injury heals as documented by the first Gastrografin study. Still the authors gave feeds only through the feeding gastrostomy for next 4 weeks following which the patient tolerated oral feeds. Hence, authors like to state 8 weeks following minor esophageal injury, it is safe to start the patient on oral feeds even though radiologically healing can be documented within 4 weeks. The next aspect is the occurrence of discitis following esophageal injury. Serial X-ray and CT scan cervical spine shows over 8 weeks the bone graft migrates anteriorly due to nonunion of bone graft after removal of the titanium cervical implant [Figure 3], [Figure 4], [Figure 5]. For CT scan evidence of discitis and bony erosion to occur it clearly takes 11–12 weeks (3 months) from the time of initial insult of esophageal injury or inoculation of the bacteria, since CT spine taken after 8 weeks reveals only anterior migration of bone graft and no gross evidence of discitis or bony destruction at C3–C4 disc space or adjacent level [Figure 5] and [Figure 7]. Thus, there is a time lag of another 3 weeks after extrusion of bone graft before definite CT evidence of discitis in both the spaces to be revealed. Based on these observations, our study supports the view, that in suspected cases of discitis or even infection at the operated site, MRI of spine with contrast is more sensitive and specific than any other investigation including CT spine.
Even though existing literature strongly advocates surgical wound debridement and discectomy and corpectomy of the adjacent spaces involved by infection after diagnosis of ASI, our case differs in it.,, We treated conservatively with parenteral antibiotics for 8 weeks followed by oral antibiotics for 4 weeks with external immobilization using cervical collar. Follow-up of this case over 5 years showed no recurrence of discitis. Radiologically, the disc spaces at both the levels were fused leading to kyphosis but clinically patient does not have any neurological deficit. Occasionally, he used to have neck pain even though he is a driver by profession which he continues to practice. Thus, we like to state that medical management with antibiotics for 12–16 weeks with external immobilization of the cervical spine after developing ASI has a role to play in the management of these cases. Successful long-term outcome could be achieved even with this line of treatment in cervical ASI. Thus, here we present a very rare case of cervical ASI caused by undetermined esophageal injury successfully treated with parenteral antibiotics and immobilization after removal of the implants and bone graft.
| Conclusion|| |
The objective is to describe a rare case of cervical ASI which occurred after an undetermined esophageal injury which lead to a series of complications in the same patient as nonunion of the bone graft followed by anterior migration of the bone graft which was surgically removed, delayed occurrence of spondylodiscitis at the same level and ASI below that level due to Klebsiella Pneumoniae which was successfully conservatively managed. ASI in the cervical region can be managed in such cases with prolonged antibiotic therapy for a minimum period of 16 weeks with external immobilization using cervical collar after treating the causative factor and removal of all foreign bodies including the implants.
I would like to acknowledge the support given by Prof. Dr. P. V. A. Mohandas, Managing Director of MIOT hospitals, Chennai and Dr. L. S. Subramaniam, Managing Director of Sri Balaji Hospitals, Chennai.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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