Treatment of chronic intractable pain is evolving in Hong Kong
Advances in treatment of chronic non-cancer pain in Hong Kong, including the use of opioids and new techniques in neuromodulation are discussed at the 13th International Symposium on Healthy Aging.
“The use of opioids and neuromodulation for management of chronic pain is widely accepted in other countries but has only been introduced in Hong Kong a few years ago,” said Dr Chi-Wai Cheung of the Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong.
“Opioids are not commonly used in Hong Kong but with careful patient selection, prescription and monitoring, some patients can be good candidates for treatment. Opioids are usually used as a last resort treatment for those who did not respond to oral medications. Guideline for opioid use in Hong Kong has been published two years ago,” Cheung added. [Hong Kong Med J 2016;22:496-505]
New variations in neuromodulation, such as the use of high frequency stimulation, cephalocaudal implantation, dorsal root ganglion stimulation, paddle leads and wireless spinal cord stimulation, were also discussed at the meeting.
“Common conditions that will likely respond to neuromodulation include failed back surgical syndrome, refractory angina, complex regional pain syndrome, neuropathic pain and postherpetic neuralgia,” Cheung mentioned.
The use of high frequency (10 kHz) spinal cord stimulation showed significant back pain relief, reduction in disability, improvement in quality of life, and reduction of opioid use in patients with chronic low back pain. Its long-term effects are, however, still undetermined. [Neuromodulation 2017;20:63-70]
“Normally, epidural insertion of electrostimulation catheters is performed in the cranial [upward] direction. This approach does not allow access to nerve roots in the lower extremities and perineal areas. Performing percutaneous cephalocaudal implantation can offset this problem,” explained Cheung. [Pain Physician 2013;16:145-153]
“Dorsal root ganglion stimulation is more target-specific and requires less energy for stimulation, but requires training and good technical expertise,” he commented.
Study results about dorsal root ganglion stimulation have been encouraging so far, with success reported in a wide range of conditions including postsurgical pain, complex regional pain syndrome and phantom pain. The therapy is, however, still young and long-term results are not yet available. [Neuromodulation 2017, doi: 10.1111/ner.12685]
“The use of paddle leads is also gaining popularity recently because it is efficient for covering a lot of painful sites and the chances of reoperation are low. However, the procedure is invasive and requires laminotomy or laminectomy,” Cheung pointed out.
Wireless spinal cord stimulation system involves the use of implanted leads with small metal receivers that receive energy wirelessly from external wearable antennas. Clinical trials are currently ongoing and results are expected to be available soon. [Curr Opin Anaesthesiol 2017;30:710-717]
“Our laboratory [in HKU] is currently undertaking investigations on spinal cord stimulation through the use of peripheral neuropathic pain animal models. We are also currently studying the importance of nestin as possible inhibitory neurons,” Cheung added.