Case report: fractured needle in the pterygomandibular space following administration of an inferior dental nerve block

Fortunately, needle fracture is a rare complication following the administration of dental local anaesthetic injections.1 Evidence seems to suggest that needle fracture is more common when giving an inferior dental nerve block than it is with other dental infiltration and block techniques. Since the introduction of disposable needles in the 1960s, along with improvements in metal alloys and manufacturing processes, needle fracture has become even less common.2 On reviewing historical literature, we came across a 1924 study by Blum,3 documenting 65 cases of broken needles over a 10-year period.

Needle fracture may occur due to:

Commonly used needles in dental practice in the UK include:4

A 32-year-old medically well female attended her dentist for routine mandibular dental extractions, for which an inferior dental nerve block on the right-hand side was required. While using a disposable 23 mm 30 gauge dental needle, and during administration of a second block, the needle fractured in the soft tissues and the dentist was unable to visualize the fragment in order to retrieve it. The proposed treatment was abandoned and the patient was referred urgently to the maxillofacial department by her GDP. On presentation, the patient was somewhat distressed by the situation. On examination, there was tenderness in the retromolar region, trismus, but no sign of the needle. Orthopantomogram and posterior-anterior mandibular radiographs revealed a linear radio-opaque object with a bend, in the pterygomandibular space, representing the needle fragment (Figures 1 and 2). The patient was admitted for exploration of the pterygomandibular space for removal of the needle under a general anaesthetic. The risk of damage to the inferior dental and lingual nerves was discussed with the patient and consent was gained.