Laser-evoked potentials: prognostic relevance of pain pathway defects in patients with acute radiculopathy

The radicular pain syndrome is a major problem in public health care that can lead to chronic back and leg pain in 30%. Ischalgia and back pain are the most prominent signs of dorsal root affection. Until now, no clinical or neurophysiological test procedure exists that evaluates the function of the dorsal root and predicts the prognosis of patients suffering from RPS. We have recently demonstrated that laser-evoked potentials (LEP) are able to demonstrate dorsal root damage. With this study, we investigated 54 patients with acute radicular symptoms and compared LEP parameters (side to side difference of latency and amplitude, transformed to a z-score) with their state of health after 3 months to calculate their predictive value for outcome prognosis. Most significantly, the latency difference between the LEP of the affected dermatome relative to the contralateral healthy dermatome was able to predict the prognosis. Latency z score above two demonstrates a 91% specificity (33% sensitivity) for a poor outcome at 3 months. A significant relation between amplitude changes and the main outcome measure could not be shown. Only extreme changes (z score >10) in amplitude show a high specificity for the persistence of ischialgia in particular (specificity 0.94; sensitivity 0.35). All other parameters, such as clinical scores or other LEP parameters, were not able to predict the outcome of patients. We propose that clinical testing using LEP with latency analysis is a useful tool for estimating the course of disease, so that patients with poor predictive parameters can be treated more invasively at early disease stages to avoid persistence of radiculopathy

Dermatomal laser-evoked potentials: a diagnostic approach to the dorsal root. Norm data in healthy volunteers and changes in patients with radiculopathy

We conducted a cross-sectional study of 40 radiculopathy patients in comparison with norm data from healthy subjects using a new electrophysiological method. Early manifestations of dorsal root impairment escape objective diagnosis by conventional somatosensory-evoked potentials due to the overlapping innervation of the affected dermatome by thickly myelinated mechanoreceptive afferents projecting to adjacent intact roots. Evidence suggested less intersegmental overlap for thermonociceptive afferents rendering laser-evoked potentials (LEP) sensitive to monosegmental dorsal root damage. Therefore we used this new method to study acute manifestations of monosegmental dorsal root pathology. Dorsal root function was tested in 12 healthy subjects and 40 sciatica patients by intraindividual interside comparison. Mechanosensibility and thermosensibility were clinically investigated. LEP were induced by moderately painful laser stimuli. The LEP were evaluated by amplitude and latency of the averaged electroencephalogram. Normal interside differences of LEP for amplitude were ±22% (lower limb) and ±35% (upper limb) and ±15 to ±16% for latency. Twenty-six patients (65%) showed significant LEP changes, mainly amplitude decreases. Six of these patients exhibited latency prolongations. Clinical testing yielded more frequent pathological results for pain compared to mechanosensibility. The study confirmed our preliminary evidence of LEP sensitivity to objectively document dorsal root impairment in patients suffering from acute monosegmental radiculopathy. This result opens the perspective of electrophysiologically differentiating the presence or absence of dorsal root pathology in patients with similar clinical symptoms but possibly different prognoses, which require different therapies

Psychosocial stress factors among patients with lumbar disc herniation, scheduled for disc surgery in comparison with patients scheduled for arthroscopic knee surgery

Returning to work after disc surgery appears to be more heavily influenced by psychological aspects of work than by MR-identified morphological alterations. It is still not known whether psychosocial factors of importance for outcome after disc surgery are present preoperatively or develop in the postoperative phase. The aim of this study was to investigate the presence of work-related stress, life satisfaction and demanding life events, among patients undergoing first-time surgery for lumbar disc herniation in comparison with patients scheduled for arthroscopic knee surgery. Sixty-nine patients with disc herniation and 162 patients awaiting arthroscopy were included in the study, during the time period March 2003 to May 2005. Sixty-two percent of the disc patients had been on sick leave for an average of 7.8 months and 14 percent of the knee patients had been on sick leave for an average of 4.2 months. The psychosocial factors were investigated preoperatively using a questionnaire, which was a combination of the questionnaire of quality of work competence (QWC), life satisfaction (LiSat9) and life events as a modification of the social readjustment scale. There were no significant differences between the two groups in terms of work-related stress or the occurrence of demanding life events. The disc patients were significantly less satisfied with functions highly inter-related to pain and discomfort, such as present work situation, leisure-time, activities of daily living (ADL) function and sleep. Patients with disc herniation on sick leave were significantly less satisfied with their present work situation than knee patients on sick leave; this sub-group of patients with disc herniation also reported significantly higher expectations in relation to future job satisfaction than knee patients. The results indicate that psychosocial stress is not more pronounced preoperatively in this selected group of disc patients, without co-morbidity waiting for first-time disc surgery, than among knee patients awaiting arthroscopy. It was notable that the disc patients had high expectations in terms of improved job satisfaction after treatment by surgery

Clinic-based training in comparison to home-based training after first-time lumbar disc surgery: a randomised controlled trial

The effectiveness of physiotherapy after first-time lumbar disc surgery is still largely unknown. Studies in this field are heterogeneous and behavioural treatment principles have only been evaluated in one earlier study. The aim of this randomised study was to compare clinic-based physiotherapy with a behavioural approach to a home-based training programme regarding back disability, activity level, behavioural aspects, pain and global health measures. A total of 59 lumbar disc patients without any previous spine surgery or comorbidity participated in the study. Clinic-based physiotherapy with a behavioural approach was compared to home-based training 3 and 12 months after surgery. Additionally, the home training group was followed up 3 months after surgery by a structured telephone interview evaluating adherence to the exercise programme. Outcome measures were: Oswestry Disability Index (ODI), physical activity level, kinesiophobia, coping, pain, quality of life and patient satisfaction. Treatment compliance was high in both groups. There were no differences between the two groups regarding back pain disability measured by ODI 3 and 12 months after surgery. However, back pain reduction and increase in quality of life were significantly higher in the home-based training group. The patients in the clinic-based training group had significantly higher activity levels 12 months after surgery and were significantly more satisfied with physiotherapy care 3 months after surgery compared to the home-based training group. Rehabilitation after first-time lumbar disc surgery can be based on home training as long as the patients receive both careful instructions from a physiotherapist and strategies for active pain coping, and have access to the physiotherapist if questions regarding training arise. This might be a convenient treatment arrangement for most patients