Ultrasound-Guided Aspiration Therapy for Surgical Site Infection After Spinal Surgery: A Report of three Cases

Aspiration Therapy for Surgical Site Infection After Spinal Surgery: A Report of three Cases. Postoperative surgical site infection in the lumbar spine is a well-recognized complication after surgery. With the prevalence of antibiotic-resistant organisms, the prevention and treatment of infection has become even more difficult and challenging, particularly in those patients with spinal instrumentation. Case/Intervention: The first patient was a 79-year-old woman with increased low-back pain in 15 days after spinal surgery. The second patient was a 49-year-old man who had tenderness to palpation and drainage at the spinal surgical site. The last one was a 72-year-old man presented with was high fever, chills and pain. They were diagnosed surgical site infection after spinal surgery and treated successfully with ultrasound-guided aspiration. Conclusion: Those cases illustrate the ultrasound-guided aspirating incisional effusion holds promise as a simple and safe technique for surgical site infection after spinal surgery.


Introduction
including microscopes or CT [1][2][3]. The infection following spinal instrumentation remains a challenging and controversial subject, as it is positively associated with prolonged hospitalization, increased healthcare costs and rate of reoperation, poorer longterm outcomes, and greater dissatisfaction with the initial surgery [4][5][6][7]. To treat SSI, surgical removal of internal fixation is sometimes required, although the loss of fixation can contribute to spinal instability [8][9][10][11]. CT-guided aspiration and drainage and drainage is a useful treatment that drains exudates, pus and necrotic tissue to reduce the chance of wound bacterial growth [12]. But these

Case 1
History and Examination. A 79-year-old woman with several years of low-back pain that radiated to her feet was described.
She had tried conservative management using pain medications or acupuncture but the pain continued. On examination she had hallux dorsiflexion muscle IV level. Superficial sensation was impaired over the lower legs and lateral dorsum of feet. Meanwhile she had a positive straight leg-raise test at 60°. An MRI study of her lumbar spine revealed L4-L5, L5-S1 para-central disc herniation.
The patient also had a history of hypertension and diabetes that required chronic, long-term medication.
Operation: This woman underwent posterior spinal L4, L5, and S1 pedicle screw fixation. Her pain improved obviously and

Discussion
Spinal operation is commonly used in the therapy for spinal disease. Post-operative surgical site infection is a dreadful complication with reported rates ranging from 0.7-20% [1][2][3][4][5]. At present, there are many modalities being used for therapy including antibiotic, vacuum sealing drainage (VSD), instrumentation removal, debridement and continuous irrigation and suction [11][12][13][14]. There remains no consensus on indications for maintenance of the stabilization devices versus removal. These devices are often removed to facilitate infection control for the bacteria associated with these infections form biofilms attached to the internal fixator.
However, reoperation means higher costs, more pain and longer hospital stay. Studies showed that significant loss of correction in deformity patients after instrumentation removal, even if stable fusion was observed. In our report described here, after undergoing posterior spinal surgery three patients developed SSI.
By aspirating incisional effusion with ultrasound-guidance and retaining stabilization devices, their symptoms, the risk of spinal instability and neurological risks decreased, resulting in increased quality of life.
It is widely agreed that deep infection should be managed with aspiration drains pus, and necrotic tissues that can hinder the antiinfective function of para-spinal muscle and granulation tissues.
Vacuum sealing drainage (VSD) is a negative-pressure technique, which can achieve safe and rapid healing of soft wounds and infections. However, these patients [13,14] required wound opening during the VSD treatment and a second surgery to close the wound, which increased patient discomfort and the expense, limited patient activity, and required advanced medical facilities. Comparing to VSD, ultrasound-guided aspiration has more advantage including small trauma, less pain, economical and convenient. In our institution we operated 1258 patients of degenerative disc diseases from Ultrasound-guided aspirating incisional effusion was performed in those patients whose infection has progressed on MRI despite appropriate antibiotic therapy. Twenty cases undergone this procedure, which all of them have received satisfactory effect. For other cases with severe infection including suppurative spondylitis and septicaemia, aspiration alone cannot completely eliminate bacteria and suggests that surgery was an effective option. For these cases, ultrasound-guided aspiration could help to identify the effusion and correctly choose and use antibiotics.

Conclusion
Based on our small experience with postoperative surgical site infection after spine surgery, we recommended an ultrasonography study to determine the effusion, to determine the infection, to determine causative organisms, to choose correct antibiotic and to aspirate effusion.