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


CONCLUSIONS
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.
Department of Anaesthesia, Cork University Hospital, Cork City, Ireland. oonaghhickey@yahoo.co.uk
Oonagh T
OT
Hickey
Siun M
SM
Burke
Parvais
P
Hafeez
Alexander L
AL
Mudrakouski
Ivan D
ID
Hayes
Catherine
C
Keohane
Mark A
MA
Butler
George D
GD
Shorten
D000328:Adult; D017586:Diskectomy / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000523:psychology / Q000601:surgery; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods / Q000523:psychology*; D017288:Pain Threshold / Q000523:psychology*; D010149:Postoperative Pain / Q000517:prevention & control / Q000523:psychology*; D010865:Pilot Projects; D011300:Preoperative Care / Q000379:methods / Q000523:psychology*; D011446:Prospective Studies; D016896:Treatment Outcome; D055815:Young Adult