Perioperative pregabalin improves pain and functional outcomes 3 months after lumbar discectomy.

BACKGROUND: Patient outcome after lumbar discectomy for radicular low back pain is variable and the benefit is inconsistent. Many patients continue to experience pain 3 months after surgery. Pregabalin, a membrane stabilizer, may decrease perioperative central sensitization and subsequent persistent pain. METHODS: Forty patients undergoing lumbar discectomy were randomly allocated to receive either pregabalin (300 mg at 90 minutes preoperatively and 150 mg at 12 and 24 hours postoperatively) or placebo at corresponding times in a double-blinded manner. Our primary outcome was the change in the present pain intensity (PPI) (visual analog scale [VAS], 0-100 mm [PPI-VAS, McGill Pain Questionnaire]) from preoperatively to 3 months postoperatively. RESULTS: The decrease in PPI-VAS score at 3 months was greater in patients who received pregabalin (37.6 +/- 19.6 mm) (mean +/- sd) than those who received placebo (25.3 +/- 21.9 mm) (P = 0.08). The Roland Morris disability score at 3 months was less in patients who received pregabalin (2.7 +/- 2.4) than in those who received placebo (5.6 +/- 4.8) (P = 0.032). Pregabalin administration was associated with greater pain tolerance thresholds in both lower limbs compared with placebo at 24 hours postoperatively. CONCLUSION: Perioperative pregabalin administration is associated with less pain intensity and improved functional outcomes 3 months after lumbar discectomy.

Determinants of outcome for patients undergoing lumbar discectomy: a pilot study.

BACKGROUND AND OBJECTIVE: One-third of patients who undergo lumbar discectomy continue to suffer from persistent pain postoperatively. Greater preoperative warmth thresholds and greater preoperative cerebrospinal fluid concentrations of stable serum nitric oxide metabolites are associated with a worse outcome. The principal objective of this study was to examine the relationship between patient outcome (defined using the Modified Stauffer-Coventry evaluating criteria) and preoperative pain perception threshold to an electrical stimulus. METHODS: A prospective observational pilot study of patients (n = 39) was performed. Quantitative sensory testing, visual analogue scales for anxiety and pain, the Hospital Anxiety and Depression (HADS) Scale and the McGill Pain Questionnaire were completed, and serum nitric oxide metabolites were measured perioperatively. Excised disc tissue was examined histologically, and immunohistochemistry for phospholipase A2 was performed. RESULTS: Ten patients (26%) had an unsatisfactory outcome. Those with a satisfactory outcome had greater preoperative pain perception thresholds over the affected dermatome, which decreased by 2 months postoperatively. These patients also demonstrated a decrease in nitric oxide metabolites from preoperatively to 18 h postoperatively. Greater preoperative HADS scores, and greater pain intensity 4 h and 24 h postoperatively were associated with an unsatisfactory outcome. CONCLUSION: Patients with a satisfactory outcome demonstrate a decrease in pain perception thresholds and plasma concentration of stable nitric oxide metabolites during the perioperative period. Patients with an unsatisfactory outcome following lumbar discectomy experience greater preoperative anxiety and greater pain during the early postoperative period. These findings justify a larger prospective observational study.

Persistent pain after mastectomy with reconstruction.

STUDY OBJECTIVE: To determine the prevalence of persistent postsurgical pain (PPSP) and its influence on functional status, and to examine associations between PPSP and single nucleotide polymorphisms of the catechol-O-methyltransferase (COMT) gene and the guanosine triphosphate cyclohydrolase 1 (GCH1) gene following mastectomy and reconstruction. DESIGN: Retrospective study. SETTING: Two teaching hospitals. PATIENTS: From the population of women who had undergone breast reconstruction following mastectomy for breast cancer over a 6-year period, 42 women agreed to participate in the assessment (55.3% of the total sample). INTERVENTIONS: The Rand 36-Item Health Survey 1.0, the Patient-Specific Functional Scale, the McGill Pain Questionnaire (long form), visual analog scales for anxiety and pain, and the Hospital Anxiety and Depression Scale were administered. Blood was taken for genetic analysis. Quantitative sensory testing was performed using a standard electrical stimulus. MEASUREMENTS: Surgical procedures, perioperative analgesic requirements, pain scores, and adjuvant therapies were noted. Height, weight, menstrual status, and arm circumference also were recorded. MAIN RESULTS: 42 (55.3%) patients took part in the assessment, and 18 (43%) reported PPSP. Those with PPSP achieved lower scores on the Patient-Specific Functional Scale (P = 0.040) and had been given more morphine perioperatively. A trend was noted between occurrence of PPSP and the val158met polymorphism of the COMT gene (P = 0.06). CONCLUSIONS: Persistent pain after mastectomy and breast reconstruction has a high prevalence (43%). Genetic mutations may contribute to the development of persistent pain following surgery; however, larger studies are required for confirmation.

Severity of acute pain after breast surgery is associated with the likelihood of subsequently developing persistent pain.

OBJECTIVES: Persistent postsurgical pain (PPSP) after surgery for breast cancer has a prevalence of 20% to 52%. Neuroplastic changes may play a role in the aetiology of this pain. The principal objective of this study was to examine the relationship between acute pain after surgery for breast cancer and the likelihood of subsequently developing PPSP. METHODS: Twenty-eight women undergoing surgery for breast cancer completed visual analogue scales for pain and anxiety, the McGill Pain Questionnaire (long form) and the Hospital Anxiety and Depression Scale. Analgesic requirements and adverse effects of analgesic therapy were noted. Quantitative sensory testing was carried out perioperatively using an electrical stimulus, and the sensation perception, pain perception, and pain tolerance thresholds were measured bilaterally at the T4 dermatomes and at the contralateral L5 dermatome. Patients with and without PPSP 3 months postoperatively were compared in terms of these parameters. RESULTS: Eight participants (28.6%) reported PPSP. Those who subsequently developed PPSP reported greater pain scores on the McGill Pain Questionnaire 5 days postoperatively than those that did not (pain rating index, P=0.014; present pain intensity, P=0.032). None had sought medical attention for their persistent pain. Patients with and without PPSP were similar in terms of mental status (anxiety and depression), analgesic consumption, adverse effects of analgesic therapy, and changes on QST. DISCUSSION: Patients who developed PPSP experienced pain of greater intensity on the fifth postoperative day than those that did not.