Altered Cortical Reorganization and Brain Functional Connectivity in Phantom Limb Pain: A Functional MRI Study.

OBJECTIVES: Functional neuroimaging studies have shown that amputees have altered cortical reorganization and functional connectivity (FC). This study aimed to investigate whether patients with phantom limb pain (PLP) and PLP-free lower limb amputees exhibit changes in corresponding primary cortical motor area/somatosensory cortex (M1/S1) cortical reorganization and supplementary motor area (SMA) network FC. The association between functional magnetic resonance imaging (fMRI) changes and clinical parameters is also explored. METHODS: A total of 10 PLP patients were matched with 10 PLP-free amputees and 10 healthy controls (HCs). Before undergoing fMRI, all participants completed questionnaires evaluating pain, anxiety, depression, and health-related quality of life. Task-related activation and regions of interest (ROI)-wise connectivity analysis were applied to differentiate the brain regions of amputees from those of HCs. Linear correlation analysis was used to evaluate the correlation between altered FC and clinical manifestations. RESULTS: As compared with HCs, PLP patients showed increased cortical activation in M1/S1 when moving the intact foot, imagining phantom big toe movement, or having the corresponding thumb stimulated. The increased FC in the SMA network included the SMA-caudate nucleus, SMA-bilateral insula, and SMA-anterior cingulate cortex. Furthermore, results of the linear correlation analysis demonstrated that this increased FC was positively correlated with VAS scores, negatively correlated with Medical Outcomes Study 36-item Short-Form (SF-36) scores, and not correlated with anxiety or depression scores. CONCLUSIONS: Phantom limb pain in lower limb amputees is associated with M1/S1 cortical reorganization and altered SMA network FC in different areas of the brain, which could help to support our understanding of the central mechanism of PLP.

The pre-amputation pain and the postoperative deafferentation are the risk factors of phantom limb pain: a clinical survey in a sample of Chinese population.

BACKGROUND: To provide an overview of phantom limb pain (PLP) in China. This includes the prevalence of PLP and possible risk factors. METHODS: In a retrospective study, telephone interviews were conducted with 391 amputation patients who underwent extremity amputations at a tertiary hospital in China. RESULTS: PLP was found in 29% of the amputees. Pre-amputation pain (OR = 10.4, P = 0.002) and postoperative analgesia (OR = 4.9, P = 0.008) were identified as high-risk factors for PLP. 82.1% of PLP patients experienced pre-amputation pain. The average pain intensity of PLP was 5.1 ± 2.2, with 31.9% having severe intensity. The effects of PLP on the quality of the PLP patients were as follows: 7.8% of the patients had to limit their daily life and 29.0% of the patients had to limit their social activities. 17.3 and 25.7% of patients experienced depression and sleeping disorder respectively, while 18.9% had loss of interest and even 16.1% of PLP patients had attempted suicide. No effective treatments were found in 78.9% of these patients. CONCLUSIONS: PLP has markedly affected the lives of patients. Pre-amputation pain and postoperative epidural analgesia might be risk factors for the phantom limb pain after amputation. Prevention of pre-amputation pain and sudden post-amputation deafferentation should be recommended to the amputees.

[A clinical trial of ultrasound-guided facet joint block in the lumbar spine to treat facet joint related low back pain].

OBJECTIVE: To determine the feasibility and clinical efficacy of ultrasound-guided facet joint injection and nerve block in lumbar facet joint for the treatment of facet-joint related low back pain. METHODS: 20 patients with facet-joint pain were randomized into two groups received block blindly (B group) or guided by ultrasound (US group) respectively. The location of needle tip was confirmed by CT in both groups, and the accuracy was computed afterwards. VAS score, puncture time and one-time puncture success rate (%) were recorded. VAS scores and pain remission rates in both groups were recorded at 30 min, 1 d, 2 d, 6 weeks after the block. RESULTS: The VAS scores were 3.3 +/- 0.4 in US group and 1.2 +/- 0.3 in B group (P < 0.05). The puncture time was (206 +/- 27) s in US group while (397 +/- 31) s in B group (P < 0.05). There were 37 facet joint blocks guided by ultrasound, in which 32 were correctly targeted with the first puncture. The success rate is 86.5%. There were 35 facet joint blocks blindly, in which 11 were correctly targeted with the first puncture. The success rate is 31.4%. The difference of one-time puncture success rate between the two groups was significant (P < 0.05). Differences of VAS and pain remission rate at half an hour after facet joint injection between B group and US group were significant (P < 0.05). There were 8, 9, 9, and 9 patients in US group obtaining a reduction in VAS scores > or = 3 at 30 min, 1 d, 2 d and 6 weeks after the procedure respectively, while the numbers of such patients were 5, 6, 5, 5 in B group (P > 0.05). After 6 weeks of follow-up, the overall remission rates were (72.3 +/- 14.0)% in US group, and (56.7 +/- 11.0)% in B group, there was no significant difference between the two groups (P > 0.05). CONCLUSION: The ultrasound-guided lumbar facet joint injection technique had a high feasibility and accuracy, and had better clinical efficacy than block blindly.

[Feasibility and accuracy of ultrasound-guided methodology in the examination of lumbar spine facet joints].

OBJECTIVE: To investigate the feasibility, accuracy of B ultrasound in the examination of joint space of lumbar spine facet joints compared with CT scan. METHODS: Ten healthy adult volunteers were enrolled. The joint space of lumbar facet joints was measured by ultrasound. To identify the spinal levels, the posterior parasagittal sonograms were obtained at levels L1 to S1. The lumbar facet joints were delineated with the help of transverse sonograms at each level. Meanwhile, the lumbar facet joints were evaluated by spiral CT on the same plane, reformatted to 1-mm axial slices. RESULTS: A total of 88 lumbar facet joints from L1 to S1 were clearly visualized in the 10 volunteers. Both ultrasound and CT measurements showed the same average depth and lateral distance of lumbar facet joint space (P > 0.05). CONCLUSION: The lumbar facet joint space can be accurately demonstrated by ultrasound.