POSITIVE ASPIRATION AND ITS SIGNIFICANCE DURING INFERIOR ALVEOLAR NERVE BLOCK - A PROSPECTIVE STUDY

Abstract

Abstract Background and aims: It is a basic rule to aspirate before injection when giving an inferior alveolar nerve block because the local anaesthetic may fail if the injection is given into a blood vessel, and the local anaesthetic solution may have undesirable systemic effects. There are reports that indicate aspiration is not performed in every injection. The aim of the present study was to assess the incidence of intravascular needle entrance in inferior alveolar nerve block injections. Patients and methods: Interns and postgraduates of our institute performed inferior alveolar nerve block injections using conventional technique in 250 patients undergoing minor oral surgical procedures. The results of aspiration were reported. Aspirable syringes and 27 gauge long needles were used, and the method of aspiration was similar in all cases.Data were analyzed using t-test. Results: 20% of inferior alveolar nerve block injections were aspiration positive. Of all injections, 15.8% were intravascular on the right side and 14.8% were intravascular on the left. There were no statistically significant differences between right and left injection sites (P = 0.778). Between the ages of 9 and 19 the incidence of intravascular penetration was significantly greater than at other ages (10/28 compared with 39/222, P = 0.04). Conclusion: Aspiration of the syringe after the needle had been placed in position for an inferior alveolar nerve block (but before the anaesthetic solution was injected) in 250 patients showed that the tip of the needle was in a blood vessel in 49 (20%). Aspiration of blood was significantly more common in patients aged 9–19 years than in all others (P=0.04). It seems that side of injection has no considerable effect in incidence of intravascular needle entrance.