Recurrent Echinococcal Infection of the Lumbar Spine: An 11 Year Follow-up
A 21-year-old male presented to the primary physician with complaints of low back ache with radicular pain to both legs without any neurological deficit eleven years ago. He was empirically started on Anti tuberculosis drugs by the primary treating surgeon. After 5 months of treatment he developed worsening of symptoms and was referred to us for further management. He came with low back ache and bilateral lower limb radiating pain. On examination he had hypoesthesia at L4 and L5 dermatome with no motor and autonomic disturbances. Computed tomogram showed bony destruction of L4 vertebrae () and magnetic resonance imaging (MRI) scan with contrast showed well defined lesions involving the L4 vertebral body, more on the left side and lower end plates of L3 and upper end plates of L5 vetebrae. The lesion measured 4×3 cm and had fluid intensity with no septation, hypo intense on T1 weighted sequence, hyperintense on T2 weighted sequences and did not show any enhancement with gadolinium (). The differential diagnosis was of giant cell tumor, aneurysmal bone cyst and hydatid cyst of L4 vertebra Chest radiograph and ultrasound abdomen was done to rule out involvement of the lungs and liver. Anterior debridement of L3-L5 vertebral body and L3 to L5 tricortical iliac crest bone grafting via anterolateral retroperitoneal approach was done. Then posterior stabilization with mono-axial screws and bone grafting of L3 to L5 was done under general anesthesia. Intra operatively the wound was washed with betadine and 20% hypertonic saline. Histopathological examination showed viable and necrotic lamellar bone enclosing fibrocellular tissue with fibrosis and necrosis. Fragments of laminated membrane lined focally by degenerate germinal layer were seen. Post surgery he recovered without complication. He was started on oral albendazole 400 mg twice a day for four weeks and this regimen was continued for 3 more cycles with 2 week interval between each cycle [] with regular monitoring of Liver Function test. Patient was reviewed at 3rd month and 6th month and thereafter annually and was asymptomatic, implant was in good position with full recovery from hypoesthesia. Eight years after the surgery he presented with low back pain and bilateral leg pain, more on the right side aggravated by walking (). He had motor power of 2/5 of the right L4, L5 myotome. Since the stainless steel implant was in situ, computerized tomogram (CT) myelography was done (). This showed soft tissue lesion involving L3, L4, and L5 vertebrae extending posteriorly into the spinal canal impinging the thecal sac and exiting L3, L4 nerve root on the right side and L4 nerve root on the left side. Soft tissue mass with a thin calcified capsule and few hypodense areas were suggestive of recurrence of the hydatid disease. Implant removal, debridement and wash out of infected tissue and posterior stabilization with poly-axial screw from L1, L2, S1, and iliac were done. He was started on oral albendazole 400 mg twice daily for 4 weeks. One month post implant exit, MRI () was done to delineate the extent of soft tissue lesion. A month later anterior retroperitoneal debridement, L4 corpectomy, L3 to L5 fusion with titanium polyaxial screws and cages and postero-lateral bone grafting was carried out. Histopathology showed that in some areas bone and marrow was replaced by amorphous granular eosinophilic necrotic tissue containing few structures resembling degenerated hydatid cyst wall with fragments of laminated membrane lined focally by degenerate germinal layer. Presence of hooklet bearing scolices confirmed the diagnosis of hydatid cyst. Postoperatively he recovered without complications and his neurological deficit improved completely. Postoperatively patient was started on oral albendazole 400 mg twice a day for four weeks, repeated after 2 weeks for two years, monitoring Liver Function once in three months. Patient was reviewed every year after surgery and at the end of 3 years plain radiograph showed implants () in good position and CT scan showed sound posterolateral fusion. MRI showed no signs of residual lesion. In view of the possibility of further recurrence patient has been advised a yearly follow-up.