A 74-year-old woman with a history of gastric cancer presented with a chief complaint of lower back pain. Subjective lower back pain emerged approximately 4 months prior to her visit to our institute.
On admission, deep tendon reflexes in both legs (patella tendon reflex (PTR) and Achilles tendon reflex (ATR)) were found to be decreased and hypoaesthesia was identified in the left L4 sensory region. Muscle weakness was observed in the left tibialis anterior muscle according to the manual muscle test (MMT), with a score of 4. Mild perianal hypoesthesia was observed. Neurologically, cauda equina syndrome and radiculopathy at and below the L4 level were identified.
Regarding magnetic resonance imaging (MRI), T1-weighted imaging showed overall signal hypointensity for both L3 and L4 vertebral bodies, although T2-weighted imaging showed signal hyperintensity presumably indicating abundant abscess accumulation in the disc space, a lesion suspected to be epidural abscess in the spinal canal, and marked compression of the dural sac (Figure 1(a)). Contrast-enhanced computed tomography (CT) showed multiple abscess formation around vertebral bodies with calcification inside (Figure 1(b)). The preoperative diagnosis was infectious spondylitis (TB or pyogenic).
Surgery was started with the patient in the lateral position under local anaesthesia. According to the PN manoeuvre, percutaneous puncture was performed into the L3/4 intervertebral disc. A sheath was inserted into the disc space to aspirate 30 mL of abscess, and lower back pain reduced immediately thereafter. Curettage was performed while checking anteroposterior and lateral views on an X-ray image intensifier. Finally, an epidural tube as the in-tube and a drainage tube of 3 mm diameter as the out-tube were indwelled in the disc space and the operation was completed. Continuous irrigation was then started.
On postoperative day 3, Mycobacterium tuberculosis was detected as Gaffky grade 2. M. tuberculosis infection was also confirmed by tuberculosis-polymerase chain reaction (TB-PCR). Irrigation was thus continued until postoperative day 16 using a washing solution of 200 mL saline containing 1000 mg streptomycin each day. Multidrug antituberculous therapy was started using pyramide (900 mg/d), isoniazid (300 mg/d), rifampicin (300 mg/d), and ethambutol (500 mg/d). Immediately after the completion of irrigation, the patient wore a lumbar brace and started rehabilitation of walking and muscle strength of the legs. Histology showed typical TB tissue with central caseous necrosis, surrounded by epithelioid cells and Langhans-type giant cells. Severe lower back pain also resolved almost completely by 1-2 weeks postoperatively.
MRI at 3 months postoperatively showed a clear tendency toward recovery of normal signal intensity in the L3 and L4 vertebral bodies on T1-weighted imaging, while most of the abscess with high signal intensity had disappeared from T2-weighted imaging. Good improvements were seen in both diagnostic imaging and clinical symptoms, with no tendency toward recurrence in blood biochemistry. All antituberculous agents were therefore discontinued at 7 months postoperatively. On MRI at 18 months postoperatively, signal intensity in vertebral bodies had completely recovered on T1-weighted imaging. No signal hyperintense regions were apparent in the disc space or epidurally to suggest abscess recurrence on T2-weighted imaging (Figure 1(c)). In addition, plain radiography indicated complete bone union at 30 months postoperatively (Figure 1(d)). At present, 7 years and 6 months after surgery, follow-up has shown good condition with no relapse of symptoms.