The Co-administration of Dexamethasone or Adrenaline With Lignocaine 2% Prologues Duration in Inferior Alveolar Nerve Block- :A Comparative Study

Background :

Oral and dental professionals were responsible for the discovery of anaesthesia, given their close day-to-day contact with pain and, hence, their motivation to seek the means to alleviate it [Greene NM; 1971]. Currently, third molar surgery (TMS) has become the model most frequently used in acute pain trials because TMS is a simple and frequently used procedure with pain moderate or severe in intensity, as well as sufficient numbers of patients, are available for the required sample size for the studies. Halsted and Hall, 1884 reported the first successful nerve block ie inferior alveolar nerve block and went on to develop nerve and regional blocking techniques [Olch PD, William S; 1975]. These developments in the field of anaesthesia are possibly the most important advances for surgical specialities all over the world. Further, improvements in agents and techniques for local anaesthesia have occurred in the past 100 years. Today's variety of local anaesthetics agents are available can be administered with minimal irritation to tissue but inadequate analgesia, systemic toxicity and adverse local tissue are three principal challenge for clinicians. Local anaesthesia provides benefits of superior pain control, improved patient satisfaction, decreased stress response to surgery, achieve haemostasis, lesser complication with wide therapeutic margins (diminished postoperative nausea and vomiting), decreased logistic requirements, and decrease overall surgical cost. Moreover, clinicians often used local anaesthesia in an effort to improve perioperative analgesia and facilitate early mobilization either as an adjunct to general anaesthesia (GA) or as the primary anaesthetic. LA has become a useful therapeutic approach for managing perioperative pain, ensuring that patients are comfortable enough to be discharged home immediately after third molar surgery, (Robert DH, Sowray JH, 1979).

A broad cross-section of surgical patients consistently ranks postoperative pain as their highest concern highlighting the necessity for prolonged postoperative analgesia [Chew ST. et al, 1998, Razi S. et al 2008]. Usually, analgesia is short-lived, lasting less than 4 hours with all most all local anaesthetic agents. Additionally, the injection technique failure is another challenge to the clinician; past studies were reported the highest failure rate ( 10-39%) with an inferior alveolar nerve block (IANB) [Hung P et al, 2006; Boonsiriseth K et al, 2013]. The researchers have been trying mixing local anaesthetic with adjuvant drugs in an attempt to prolong analgesia from nerve blocks in brachial plexus, femoral, intercostal and interscalene nerve blocks. They found limited success with co-administration of adjuvants such as epinephrine, α2 agonist (i.e. clonidine and dexmedetomidine) opioids, ketamine, midazolam and hyaluronidase [Horliana et al, 2008]. However, co-administration of the dexamethasone was found to be effective for perioperative analgesia in an ample of TMS studies and other nerve blocks study both in the lab and clinical studies.

Effective local anaesthesia is arguably the single most important pillar upon which modern dentistry stands. Many agents are not available in the markets of Nepal that provide a rapid onset of surgical anaesthesia with adequate duration. Local anaesthetic agents that selectively inhibit pain pathways without interrupting transmission of other sensory pathways are not currently available. However, an accident finding of a previous study was impressive to increase the duration of analgesia with lignocaine 2% while the researcher tried to determine the effect of dexamethasone 8 mg on postoperative sequelae after TMS. Following after publication of the result, ample similar studies were conducted and found prolongation in the duration of IANB after injecting dexamethasone in pterygomandibular space. The current study is designed to search for a better quality of perioperative analgesics with a single injection of dexamethasone and lignocaine in IANB preoperatively during TMS. The null hypothesis for this study is "an addition of 2 ml dexamethasone (4mg/ml) or adrenaline ( 0.01mg/ml) to 2ml lignocaine (20 mg/ml) should have same effect of analgesia during TMS''. The purpose of the current study is to evaluate the effectiveness and safety profiles of coadministration of dexamethasone (4mg/ml) or adrenaline ( 0.01mg/ml) with lignocaine 2% in IANB during TMS. Best of my knowledge this is a unique and novel clinical trial, probably the first trial which aim to overcome three principal challenges of local anaesthesia with a single injection during TMS.

Methodology: