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.

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.