Safety and Efficacy of Addition of Hyaluronidase to Lidocaine and Bupivacaine in Scalp Nerves Block in Elective Craniotomy Operations, Comparative Study

Patients undergoing craniotomy operations are susceptible to many injurious stimuli such as skin incision, insertion of cranial pins, dural incision, dural and skin closure. They cause different levels of nociception and these stimuli can result in sudden increases in blood pressure and heart rate due to triggering stress response.

Strategies to blunt these noxious stimuli and attenuate this stress response include administration of systemic opioids, deepening the level of anaesthesia. Scalp nerves block by local anaesthetics also can be used.

However, most systemically administered medications studied for post-craniotomy pain usually associated with side effects such as sedation, nausea, and vomiting and depressed ventilation such events are particularly important for post-craniotomy patients.

Using regional aesthetic techniques in addition to general anaesthesia have been conducted as multimodality managements for post-craniotomy pain and to decrease systemic administration of analgesics and hence decrease their systemic complications.

The stress response is the hormonal and metabolic changes that follow injury or trauma. This includes wide range of endocrinological and immunological effects. The stress response to surgery is characterized by increased secretion of pituitary hormones and activation of the sympathetic nervous system. Hypothalamic activation of the sympathetic autonomic nervous system results in increased secretion of catecholamines from the adrenal medulla and release of norepinephrine from presynaptic nerve terminals. IL-6 is produced in substantial quantities at the site of a surgical wound.IL-6 enters the circulation, and its concentration correlates with the severity of surgery and thus with the magnitude of the tissue injury. At 24 to 36 h after surgery, the levels of IL-6 in the plasma reach preoperative values, because its production is attenuated. Postoperative pain behaves like wound on plasma IL-6: intense postoperative pain correlates with the magnitude of tissue injury and subsides days after. Pain in the first 24 hours after brain surgery is a significant problem, with 60% to 80% of patients experiencing moderate to severe pain.

Blockade of scalp innervation which anesthetises both the superficial and deep layers of the scalp, was used as a means of decreasing hemodynamic reactions during and after craniotomy operations. Various protocols to control postoperative pain were suggested, including infiltration of the scalp with local anaesthetics. These include the use of 0.5% bupivacaine combined with additional lidocaine 2 %.

Hyaluronidase is a naturally produced enzyme, it's produced by various types of bacteria, and primary helps bacteria to dissolve hyaluronic acid that constitutes major component of the connective tissue substance thus helping spread of other bacterial products. On December 2005, the FDA approved a synthetic (recombinant or rDNA) human hyaluronidase. The addition of hyaluronidase to local anaesthetics has been shown to enhance safely and effectively the diffusion of the drug, thereby increasing the analgesic efficacy especially in the first minutes after injection

Inclusion criteria

• ASA Ι and II.
• Both males and females, age (18-60) years.
• Supine position.
• Glasco coma scale more than 12.
• Elective craniotomy operations.

Exclusion criteria

• ASA ΙII or IV
• History of allergy to the study drugs.
• Surgery to remove pituitary tumours or affecting pituitary hormones.
• Glasco coma scale less than 12.
• The need for postoperative ventilation.