Discal pseudocyst after lumbar tubular microdiscectomy: case report and evidence-informed management with literature review.

Background: Postoperative discal pseudocyst (PDP) is a rare but increasingly recognized cause of recurrent radiculopathy after lumbar discectomy. Although its true incidence, risk factors, and natural history remain poorly defined, awareness of this entity is important to avoid misdiagnosis as recurrent disc herniation. This report describes PDP following tubular microdiscectomy and highlights diagnostic and management considerations. Case Description: A 21-year-old male developed left S1 radiculopathy secondary to an L5-S1 disc protrusion. After 6 weeks of unsuccessful conservative treatment, he underwent left L5-S1 tubular microdiscectomy, which immediately relieved the symptoms. Several months later, identical radicular pain recurred. Contrast-enhanced magnetic resonance imaging (MRI) demonstrated a 1.0 cm extradural cyst at the prior discectomy site (T1-hypointense, T2-hyperintense) with a narrow tract communicating with the L5-S1 disc and compression of the left S1 nerve root without a recurrent disc fragment. We performed revision surgery involving cyst drainage, cyst wall excision, and coagulation of the annular defect. Histopathology confirmed a fibrous pseudocyst. The patient's symptoms resolved completely postoperatively. Conclusions: PDP should be considered in patients presenting with recurrent radiculopathy after lumbar discectomy. Recognition of disc-cyst communication on MRI is critical for accurate diagnosis and differentiation from recurrent disc herniation. A stepwise management approach, ranging from observation to minimally invasive drainage or surgical excision with treatment of the annular defect, can result in favorable outcomes and help avoid misdiagnosis as failed back surgery syndrome.