Pain 5 years after instrumented and non-instrumented posterolateral lumbar spinal fusion

Abstract

Pain drawings have been used in spine surgery for diagnostic use and psychological evaluation of fusion candidates; they have rarely been used to evaluate pain status after spinal fusion. This study is a 5-year follow-up on a randomised clinical trial assigning patients to posterolateral spinal fusion with or without pedicle screw instrumentation. Patients were mailed a pain drawing and questionnaires including questions regarding work, social status, smoking status, the Dallas Pain Questionnaire (DPQ), and the Low Back Pain Rating Scale (LBPRS). Pain drawings were scored using a visual inspection method and a surface-based point scoring and evaluated for the presence of donor site pain. Pain drawings from 109 patients (87% of the initially included patients), 56 men and 53 women, mean age at follow-up 51 years, were analysed. Fifty-three patients had undergone an instrumented fusion and 56 a non-instrumented fusion. Some presence of low back pain was marked by 79% and leg pain by 69%. Sixty-two percent of the pain drawings were classified as "organic" and 38% as "non-organic". There was no difference between the instrumented and the uninstrumented group. DPQ and LBPRS scores were higher in the non-organic group ( P=0.007). Using the point scoring, no difference between the instrumented and the uninstrumented group was seen. The results of the point scoring were found to correlate with the DPQ and LBPRS scores ( P=0.001). Working patients (39%) had significantly better scores than the rest. Ten percent of the patients had donor site pain. Twenty percent of spinal fusion patients are totally pain free at 5-year follow-up. Ten percent still experience donor site pain. In general, instrumentation does not affect the amount and localisation of pain 5 years after lumbar spinal fusion surgery. The pain drawing seems to be a valuable tool when following spinal fusion patients, but its use as prognostic marker in connection with fusion surgery needs further investigation.

Fig. 1. A

Pain drawing classified as "organic". This pain drawing was also classified in the group with donor site pain due to the use of the "::::" symbols in the area of the right buttock. B Pain drawing classified as "non-organic" and also with donor site pain, due to the use of "NNN" symbols in the area of the right buttock, which do not appear elsewhere on the lower back. C Pain drawing classified as "organic"; no donor site pain. The same symbols are used to mark back and radiating pain. D The pain drawing with the 16 areas used for the pain sites score

Fig. 2.

Boxplot of the score in the four Dallas Pain Questionnaire (DPQ) categories according to the classification obtained using the visual inspection method