A 64-year-old woman was referred to our hospital with lower back pain and a history of surgery for leg varicose veins. Lower back pain had emerged about 3.5 months prior to her visit to our institute, with gradual worsening. The patient complained that lower back pain had never improved since onset and had been exacerbated by even slight exercise such as standing and walking.
Regarding MRI, T1-weighted imaging showed overall signal hypointensity in both L2 and L3 vertebral bodies, whereas T2-weighted imaging showed signal hyperintensity presumably indicating abscess accumulation in the disc space extending to inside the L2 vertebral body. Subsequent gadolinium-enhanced imaging showed diffuse contrast in both L2 and L3 vertebral bodies and rim enhancement around the abscess in the right psoas muscle (Figure 2(a)). CT showed a destructive change in the L2 vertebral endplate, and cavitations >=10 mm in diameter were found in vertebral bodies (Figure 2(c)). Preoperative diagnosis was infectious spondylitis (TB or pyogenic).
Surgery was performed similar to that described for Case 1. A sheath was inserted into the L2/3 disc space to allow curettage of infected disc tissue. Finally, a 3 mm diameter in-tube and a 5 mm diameter drainage tube as the out-tube were indwelled in the disc space and the operation was completed. Continuous irrigation was started.
Histology on postoperative day 9 showed epithelioid cells centred around caseous necrosis, and QuantiFERON TB-2G showed strongly positive results. TB spondylitis was therefore finally diagnosed. Irrigation was performed until postoperative day 12 using only 250 mL of saline each day. Multidrug antituberculous therapy was started using isoniazid (300 mg/d), rifampicin (450 mg/d) and ethambutol (750 mg/d). After completion of irrigation, the patient wore a lumbar brace and started rehabilitation, mainly for walking. Strong lower back pain also disappeared by about 1-2 weeks postoperatively.
MRI at 3 months postoperatively showed recovery to normal signal intensity from signal hypointensity in the L2 and L3 vertebral bodies, except for the cavity area on T1-weighted imaging. On T2-weighted imaging, part of the signal hyperintense area remained, but was restricted to the disc space and vertebral bodies, with disappearance of abscess in the right iliopsoas muscle (Figure 2(b)). By 6 months postoperatively, diagnostic imaging showed good improvement, as did clinical symptoms. There was no evidence of recurrence from blood biochemistry. Administration of all antituberculous agents was thus discontinued at 6 months postoperatively. At 12 months, signal intensity in L2 and L3 vertebral bodies had normalized on T1-weighted imaging. No signal hyperintense regions were seen in the disc space, inside vertebral bodies or in the psoas muscle on T2-weighted imaging.
By 6 months postoperatively, CT showed repair of the L2 vertebral body cavity and bone remodelling, and the cavities was clearly reduced. At 12 months postoperatively, the cavity was completely repaired and disappeared (Figure 2(d)). At the time of writing, although complete bone union has not been achieved, follow-up shows good condition without relapse of symptoms at 24 months postoperatively.