Neuropathic Pain After Dental Implant Surgery: Literature Review and Proposed Algorithm for Medicosurgical Treatment.

The objective of this study is to establish an algorithm for the medicosurgical treatment of dental implant-induced neuropathic pain. The methodology was based on the good practice guidelines from the French National Authority for Health: the data were searched on the Medline database. A working group has drawn up a first draft of professional recommendations corresponding to a set of qualitative summaries. Consecutive drafts were amended by the members of an interdisciplinary reading committee. A total of 91 publications were screened, of which 26 were selected to establish the recommendations: 1 randomized clinical trial, 3 controlled cohort studies, 13 case series, and 9 case reports. In the event of the occurrence of post-implant neuropathic pain, a thorough radiological assessment by at least a panoramic radiograph (orthopantomogram) or especially a cone-beam computerized tomography scan is recommended to ensure that the tip of the implant is placed more than 4 mm from the anterior loop of the mental nerve for an anterior implant and 2 mm from the inferior alveolar nerve for a posterior implant. Very early administration of high-dose steroids, possibly associated with partial unscrewing or full removal of the implant preferably within the first 36-48 hours after placement, is recommended. A combined pharmacological therapy (anticonvulsants, antidepressants) could minimize the risk of pain chronicization. If a nerve lesion occurs in the context of dental implant surgery, treatment should be initiated within the first 36-48 hours after implant placement, including partial or full removal of the implant and early pharmacological treatment.

Three-phase Bone Scintigraphy Can Predict the Analgesic Efficacy of Ketamine Therapy in CRPS.

OBJECTIVES: The efficacy of ketamine in relieving complex regional pain syndrome (CRPS) lacks predictive factors. The value of three-phase bone scintigraphy (TPBS) was assessed for this purpose. MATERIALS AND METHODS: TPBS was performed in 105 patients with unilateral, focal CRPS of type 1 before 5 days of ketamine infusions. Tracer uptake was measured in the region of interest concerned by CRPS and the contralateral homologous region. For the 3 scintigraphic phases (vascular, tissular, and bone phases), an asymmetry ratio of fixation was calculated between the affected and the unaffected sides (vascular phase [VPr], tissular phase [TPr], and bone phase [BPr]). Ketamine efficacy was assessed on pain intensity scores. RESULTS: Ketamine-induced pain relief did not correlate with VPr, TPr, and BPr, but with the ratios of these ratios: BPr/TPr (r=0.32, P=0.009), BPr/VPr (r=0.34, P=0.005), and TPr/VPr (r=0.23, P=0.02). The optimum cut-off value for predicting the response to ketamine therapy was >1.125 for BPr/TPr, >1.075 for BPr/VPr, and >0.935 for TPr/VPr. The combination of increased values of BPr/TPr, BPr/VPr, and TPr/VPr was highly significantly associated with ketamine therapy outcome. CONCLUSIONS: The relative hyperfixation of the radioactive tracer in the limb region concerned by CRPS in phases 2 and 3 versus phase 1 of TPBS correlated positively to the analgesic efficacy of ketamine. This study shows for the first time the potential predictive value of TPBS regarding ketamine therapy outcome. In addition, these results suggest that the analgesic action of ketamine is not restricted to "central" mechanisms, but may also involve "peripheral" mechanisms related to tissue inflammation and bone remodeling.