Background: Despite successful surgery, 30% of patients with painful radiculopathy complain of persistent pain on long-term follow up. 

Aim: To investigate if there is an association between pre-surgical altered sensory nerve function and clinical outcome at 12 months post microdiscectomy.

Methods: Quantitative sensory testing was performed in 53 patients (mean age 38±11years, 26 females) with unilateral L5/S1 radiculopathy in their main pain area (MPA) and affected dermatome. An improvement <30% on the Oswestry Disability Index (ODI) was defined as ‘no improvement’.

Results: At baseline, compared to healthy controls, patients with lumbar radiculopathy were characterised by a significant loss of function in the symptomatic leg in the MPA (thermal, mechanical, vibration detection, mechanical pain threshold, mechanical pain sensitivity p<0.027) and dermatome (thermal, mechanical, vibration detection p<0.002) and by a gain of function (cold sensitivity) in the MPA (p<0.001). At 12 months, seven out of 48 patients (15%) reported <30% improvement on the ODI. Logistic regression analysis revealed that the mechanical detection threshold in the MPA was significantly associated with group outcome (OR 2.61, 95% CI 1.19-5.74, p = 0.0170). At baseline the ‘improvers’ demonstrated a larger loss of function in mechanical detection compared to the ‘non-improvers’.

Conclusions: Results seem to suggest that pre-surgical mechanical detection thresholds measured in the MPA may be predictive of clinical outcome after lumbar microdiscectomy.

Acknowledgement: Government of Western Australia, Department of Health and Raine Medical Research Foundation; School of Physiotherapy and Exercise Science, Curtin University; Research Advisory Committee, Sir Charles Gairdner Osborne Park Health Care Group; Arthritis Australia (The Eventide Homes Grant)

QUANTITATIVE SENSORY TESTING PROFILES OF PATIENTS WITH LUMBAR RADICULOPATHY - DO THEY ASSIST IN PREDICTING CLINICAL OUTCOME AFTER SURGERY?