Tropical pyomyositis of erector spinae complicated with spinal epidural abscess.

Study Design: This is a retrospective case series.

Objective: Tropical pyomyositis of erector spinae muscle (ESPM) is a rare muscular infection which may extend into the intraspinal canal to become spinal epidural abscess (ESPM-SEA). If left untreated, it may cause catatrophic spinal cord dysfunction and lead to irreversible paralysis. A series of eight such cases is presented, in order to provide proper surgical options and clarify the prognostic factors of the disease.

Summary Of Background Data: Merely six sporadic case reports had been found in the literature. Surgical debridement and laminectomy to drain the intraspinal abscess combined with systemic antibiotics were the choice of treatment to treat the disease with good therapeutic effect.

Methods: Inpatient charts of the patients were reviewed. The therapeutic effect and functional neurological recovery are correlated with the demographic characteristics of the patients, neurological deficits before drainage, and the different procedures of drainage.

Results: Old age, long ESPM-SEA (>6.5 vertebral segments), spinal cord dysfunction as well as complete paralysis before the interventional procedures are significantly correlated with poor functional neurological recovery (Sperman's coefficient correlation, all p<0.05). Pig-tail drainage of ESPM combined with adequate systemic antibiotics could cure if infection presents with lumbar radiculopathy only, but it failed to rescue the spinal cord dysfunction in two patients present with complete paralysis. Surgical drainage of ESPM with mini-laminotomy to drain ESPM-SEA combined with systemic antibiotics provided good functional recovery of patients, despite of prolonged pre-operative complete paralysis.

Conclusion: Early drainage of the ESPM and related epidural abscess combined with systemic antibiotics can provide excellent therapeutic effect of ESPM-SEA. Open drainage with mini-laminotomy is superior to pig-tail drainage when spinal cord dysfunction occurred associated with ESPM-SEA.