LAUSR

Significant complications from subdermal insertion of a contraceptive implant in the medial upper arm are rare; a UK Government drug safety update indicating the risk of intravascular insertion was published in 2016.We report the introduction of an implant into the ulnar nerve sheath. Introduction of a contraceptive implant into the medial aspect of the distal left upper arm was followed 5 min later by the patient reporting pins and needles in the arm and tips of the left ring and little fingers. The implant was not palpable. 2 h later loss of sensation was apparent in these fingers; clinical review was unrevealing. Ultrasound suggested the implant was lying between the ulnar nerve and blood vessel in the medial upper arm. At surgery the implant was found within the left ulnar nerve sheath and removed.3 months post surgery the numbness in the little finger had resolved but reduced sensation was still evident over the dorso-ulnar hand and distal forearm with hypersensitivity over the ulnar styloid, weakness was not apparent. Nerve conduction studies revealed the left dorsal ulnar sensory NAP was small when compared to the right side (13 vs. 31 microvolts).The left digit 5 sensory NAP was normal amplitude. Motor studies showed mild slowing in the left ulnar nerve around the elbow. While publications and warnings have highlighted the rare occurrence of intravascular insertion, the neurovascular bundle is at risk hence drug company advice to avoid the sulcus between biceps and triceps. This case indicates fascicular damage to the ulnar nerve.