An unusual complication of sacral nerve root injury following bone marrow harvesting: a case report.

Background: Hematopoietic stem cell transplantation (HSCT) remains an important therapeutic option for many hematologic malignancies. Bone marrow harvesting from an appropriate donor must be conducted for hematopoietic stem cell transplantation (HSCT). Many previous studies show complications of the recipient after hematopoietic stem cell transplantation (HSCT). However, complications of the donor after bone marrow harvesting are rare. We here report a unique case of a patient who developed sacral nerve root injury after bone marrow harvesting.

Case Presentation: A 26-year-old man was admitted to our medical center complaining of acute onset painful burning and tingling sensation at the left posterior thigh and calf. He was a bone marrow donor for his brother's bone marrow transplantation. He had underwent a bone marrow harvesting procedure two days before admission as a bone marrow donor, using both posterior superior iliac spine (PSIS) as the puncture site. Pelvic magnetic resonance image (MRI) showed enhancement around the left S2 nerve root in T1 and T2-weighted images. Nerve conduction studies (NCS) revealed normal conduction velocity and amplitude on both lower extremities. Electromyography (EMG) presented abnormal spontaneous activity and neurogenic motor unit potentials on the S2-innervated intrinsic foot muscle and gastrocnemius, soleus muscle on the left. The patient was treated with pregabalin for pain control. The patient was followed up after 3, 6, and 12 months. Neuropathic pain improved to Visual Analogue Scale (VAS) 1, and recovery state was confirmed by re-innervation patterns of motor unit potentials in electromyography.

Conclusion: Bone marrow harvesting is a relatively safe procedure. However, variable complications may occur. Accurate anatomical knowledge and carefulness are required to avoid sacral nerve root injury when performing the bone marrow harvesting procedure.