Jianguo Cheng

Evidence-based knee injections for the management of arthritis.

OBJECTIVEnArthritis of the knee affects 46 million Americans. We aimed to determine the level of evidence of intraarticular knee injections in the management of arthritic knee pain.nnnMETHODSnWe systematically searched PUBMED/MEDLINE and the Cochrane databases for articles published on knee injections and evaluated their level of evidence and recommendations according to established criteria.nnnRESULTSnThe evidence supports the use of intraarticular corticosteroid injections for rheumatoid arthritis (1A+ Level), osteoarthritis (1A+ Level), and juvenile idiopathic arthritis (2C+ Level). Pain relief and functional improvement are significant for months up to 1 year after the injection. Triamcinolone hexacetonide offers an advantage over triamcinolone acetonide and should be the intraarticular steroid of choice (2B+ Level). Intraarticular injection of hyaluronate may provide longer pain relief than steroid injection in osteoarthritis (2B+ Level). It can also be effective for rheumatoid arthritis knee pain (1A+ Level). However, it is only recommended for patients with significant surgical risk factors and for patients with mild radiographic disease in whom conservative treatment has failed (2B± Level). Botulinum toxin type A injection is effective in reducing arthritic knee pain (2B+ Level), and so is tropisetron (2B+ Level) and tanezumab (2B+ Level). The new agents, such as rAAV2-TNFR:Fc, SB-210396/CE 9.1, and various radioisotopes have provided various degrees of success, but their long-term safety and efficacy remains to be determined.nnnCONCLUSIONSnWe conclude that strong evidence supports the use of intraarticular knee injection as a valuable intervention in the continuum of management of arthritis between conservative treatment and knee surgeries.

Comparative outcomes of cooled versus traditional radiofrequency ablation of the lateral branches for sacroiliac joint pain.

Objectives:Sacroiliac joint pain is a common cause of low back pain (LBP). Cooled radiofrequency ablation (c-RFA) of the lateral branches was recently introduced with the hypothesis that it creates larger lesions to overcome the anatomic variability of the lateral branches and achieve better outcomes as compared with the traditional radiofrequency approach (t-RFA). The objective of this comparative study is to determine if c-RFA is superior over t-RFA in providing longer pain relief. Methods:Data on 88 patients were retrospectively collected between January 2006 and June 2009. Patients’ pain relief was registered as <50%, 50% to 80%, or >80% at 1, 3, 6, and 12 months after procedure. The duration of pain relief, defined as the time until the patient reported <50% pain relief, served as our primary outcome. Demographic, morphometric, and procedural characteristics were analyzed using standard descriptive statistics and univariable tests. The relationship between RFA technique and duration of pain relief was evaluated using multivariable Cox regression. Results:Among the 88 patients, 30 received t-RFA and 58 received c-RFA. We did not find a significant univariable relationship between RFA technique and duration of pain relief either before (P=0.76, Sun test) or after (P=0.95, Wald test) adjusting for the potentially confounding variables. Both cooled and traditional RFAs provided >50% pain reduction for 3 to 6 months in majority of the patients. Discussion:This study did not reveal evidence that c-RFA of the lateral branches provides longer relief of sacroiliac joint pain as compared with t-RFA.

Botulinum Toxin Decreases Hyperalgesia and Inhibits P2X3 Receptor Over-Expression in Sensory Neurons Induced by Ventral Root Transection in Rats

OBJECTIVESnWe aim to determine the effects of Botulinum toxin type A (BTX-A) on neuropathic pain behavior and the expression of P2X(3) receptor in dorsal root ganglion (DRG) in rats with neuropathic pain induced by L5 ventral root transection (L5 VRT).nnnMETHODSnNeuropathic pain was induced by L5 VRT in male Sprague-Dawley rats. Either saline or BTX-A was administered to the plantar surface. Behavioral tests were conducted preoperatively and at predefined postoperative days. The expression of P2X(3) receptors in DRG neurons was detected by immunoreactivity at postoperative days 3, 7, 14, and 21.nnnRESULTSnThe number of positive P2X(3) neurons in the ipsilateral L5 DRG increased significantly after L5 VRT (P<0.001). This increase persisted for at least 3 weeks after the operation. No significant changes in P2X(3) expression were detected in the contralateral L5, or in the L4 DRGs bilaterally. Subcutaneous administration of BTX-A, performed on the left hindpaw at days 4, 8, or 16 post VRT surgery, significantly reduced mechanical allodynia bilaterally and inhibited P2X(3) over-expression induced by L5 VRT.nnnCONCLUSIONSnL5 VRT led to over-expression of P2X(3) receptors in the L5 DRG and bilateral mechanical allodynia in rats. Subcutaneous injection of BTX-A significantly reversed the neuropathic pain behavior and the over-expression of P2X(3) receptor in nociceptive neurons. These data not only show over-expression of purinergic receptors in the VRT model of neuropathic pain but also reveal a novel mechanism of botulinum toxin action on nociceptive neurons.

Botulinum toxin type a reduces hyperalgesia and TRPV1 expression in rats with neuropathic pain

OBJECTIVEnWe aim to determine the effects of botulinum toxin type A (BTX-A) on the thresholds of pain and the expression of transient receptor potential vanilloid type 1 (TRPV1) in the dorsal root ganglion (DRG) in rats with neuropathic pain induced by selective ventral root transection (VRT).nnnMETHODSnNeuropathic pain was induced by transection of the lumbar 5 ventral root in male Sprague-Dawley rats. BTX-A or saline was administered to the plantar surface by subcutaneous injection. SB366791 (an inhibitor of TRPV1) was administered intraperitoneally. Behavioral tests were conducted preoperatively and at predefined postoperative days. The expression of TRPV1 was detected and quantified by immunohistochemistry and Western blotting at postoperative days 3, 7, 14, and 21.nnnRESULTSnTRPV1 expression increased significantly in the L4 ∼5 dorsal root ganglia 7 days after L5 VRT compared with the sham-operated control (Pu2009<u20090.05). This increase persisted for at least 21 days. The thresholds of foot withdrawal to mechanical and thermal stimulation decreased significantly as well. Subcutaneous injection of BTX-A significantly and dose-dependently reduced the expression of TRPV1 (Pu2009<u20090.05) and partially reversed the pain thresholds.nnnCONCLUSIONnUpregulation of TRPV1 expression in the DRG is an important mechanism of neuropathic pain induced by the VRT. The analgesic effect of BTX-A is most likely mediated through reduction of TRPV1 expression in the nociceptors.

Response to Letter to Editor: Sacroiliac Steroid Injections Do Not Predict Ablation Relief—Not a Surprise

Dear Editor:nnOn behalf of my colleagues, I wanted to thank Dr. Mel Cusi et al. for their interest in the findings from one of our recent studies of sacroiliac joint (SIJ) pain, which was presented in the 28th Annual Conference of AAPM ⇓. I appreciate their comments that support the conclusion of our study and provide a plausible explanation for our findings.nnDiagnosing SIJ pain remains a challenge largely due to the lack of specific and sensitive tests ⇓. It has been recognized that solitary provocative maneuvers have little diagnostic value. False negatives are common because large forces are needed to stress the joint due to the large size and the immobility of the SI interface. Also, false-positive tests can be …