Neuropathic complications of mandibular implant surgery: review and case presentations

Injuries to trigeminal nerves during endosseous implant placement in the posterior mandible appear to occur acutely in approximately 5-15 of cases, with permanent neurosensory disorder resulting in approximately 8%. Nerve lateralization holds even higher risks from epineurial damage or ischaemic stretching. Neuropathy from implant compression and drill punctures can result in neuroma formation of all types, and in some cases precipitate centralized pain syndrome. Two patterns of clinical neuropathy are seen to result; hypoaesthesias with impaired sensory function, often seen with phantom pain, and hyperaesthesias with minimal sensory impairment but presence of much-evoked pain phenomena. The clinician must differentiate, through careful patient questioning and stimulus-response testing, those patients who are undergoing satisfactory spontaneous nerve recovery from those who are developing dysfunctional or dysaesthetic syndromes. Acute nerve injuries are treated with fixture and nerve decompression and combined with supportive anti-inflammatory, narcotic and anti-convulsant therapy. Surgical exploration, neuroma resection and microsurgical repair, with or without nerve grafting, are indicated when unsatisfactory spontaneous sensory return has been demonstrated, and in the presence of function impairment and intractable pain.