The hypothesis of this study is that Gabapentin or Amitriptyline has no role in preemptive analgesia to reduce postoperative pain after lumbar diskectomies.

Pain suppression plays a decisive role in patients' satisfaction following lumbar diskectomies, as the psychological component of the pain is a major cause of treatment failure.

Controversy exists whether preemptive prescription of gabapentin, as a known contributor to reduce postoperative pain, has a role in patients undergoing laminectomy for lumbar diskectomy or spinal canal stenosis.The aim of this study is to test the efficacy of amitriptyline and gabapentin in this group of neurosurgical patients.

Inclusion Criteria:

• Signed Informed Consent
• Age:18 to 60
• Weight: 60 to 80 Kg
• ASA Class: I,II
• Concordant physical and imaging findings in favor of symptomatic lumbar disk herniation
• Single level lumbar disk herniation unresponsive to medical treatment

Exclusion Criteria:

• Previous consumption of Gabapentin or Amitriptyline
• Known allergy to investigated drugs
• Reluctant to sign informed consent
• Previous history of intolerance to narcotics
• Simultaneous lumbar diskectomy and a fusion technique
• Known renal failure
• Pregnancy
• Contraindications to Amitriptyline or Gabapentin prescription
• Unable to use PCA
• Habitual use of alcohol or opium
• History of analgesic consumption during the last 24hours