The Physiology of Stimulation-Produced Analgesia

Impaired Lymphatic Drainage and Interstitial Inflammatory Stasis in Chronic Musculoskeletal and Idiopathic Pain Syndromes: Exploring a Novel Mechanism

A normal functioning lymphatic pump mechanism and unimpaired venous drainage are required for the body to remove inflammatory mediators from the extracellular compartment. Impaired vascular perfusion and/or lymphatic drainage may result in the accumulation of inflammatory substances in the interstitium, creating continuous nociceptor activation and related pathophysiological states including central sensitization and neuroinflammation. We hypothesize that following trauma and/or immune responses, inflammatory mediators may become entrapped in the recently discovered interstitial, pre-lymphatic pathways and/or initial lymphatic vessels. The ensuing interstitial inflammatory stasis is a pathophysiological state, created by specific pro-inflammatory cytokine secretion including tumor necrosis factor alpha, interleukin 6, and interleukin 1b. These cytokines can disable the local lymphatic pump mechanism, impair vascular perfusion via sympathetic activation and, following transforming growth factor beta 1 expression, may lead to additional stasis through direct fascial compression of pre-lymphatic pathways. These mechanisms, when combined with other known pathophysiological processes, enable us to describe a persistent feed-forward loop capable of creating and maintaining chronic pain syndromes. The potential for concomitant visceral and/or vascular dysfunction, initiated and maintained by the same feed-forward inflammatory mechanism, is also described.

Acupuncture Studies on Pain

The relegation of acupuncture to complementary therapy ignores the history of its development and restricts possibilities for its clinical use and further research. Clinical studies with randomised, controlled trials and double blinding require reconsideration and adaptation when using acupuncture for treatment when multiple patient and treatment variables are involved.

Ample experimental evidence exists for acupuncture to be considered as a modality of peripheral sensory stimulation, but present clinical research has not incontrovertibly validated the use of acupuncture on patients with chronic pain. A basic understanding of the neuro-physiology of pain and its differentiation does provide better indications for its use. More consistent results may then be obtained, as seen from a few recent studies.

Acupuncture in Modern Medicine

Acupuncture, developed thousands of years ago in the Orient, is increasingly being integrated into modern Western Medicine. Its neurophysiological basis is partly understood, and controlled trials are demonstrating its efficacy and safety.

The Use of Acupuncture for Pain Relief in a Chinese Hospital Clinic

This study formed part of a medical student elective and was conducted over a six-week period from April to June in the Acupuncture Clinic of the First Teaching Hospital of Tianjin Traditional Medical College, China. It is a descriptive cross-sectional study investigating the painful conditions for which Chinese consult an acupuncturist. The effectiveness of acupuncture as an analgesic was assessed subjectively using a visual analogue scale to estimate the amount of pain before and after treatment. A significant improvement was seen following acupuncture. The patients’ own views on the efficacy of acupuncture in controlling their pain were also noted: this resulted in a mean effectiveness rating of 74.4%.

Acupuncture ( zhēn jiǔ) - an emerging adjunct in routine oral care

Acupuncture ( Zhēn Jiǔ) ('acus' (needle) + 'punctura' (to puncture)) is the stimulation of specific points along the skin of the body involving various methods such as penetration by thin needles or the application of heat, pressure, or laser light. Acupuncture ( Zhēn Jiǔ) aims to treat a range of medical and dental ailments, though is most commonly used for pain relief. This article reviews about the various possible roles of acupuncture ( Zhēn Jiǔ) in clinical dental practice. Acupuncture ( Zhēn Jiǔ) has potential in supplementing conventional treatment procedures by its diverse applicability outreach. Role of acupuncture ( Zhēn Jiǔ) in dental practice has been well supported by clinical trials. Its role in alleviating facial pain, pre-operative and post-operative dental pain has led to its widespread application. Its role as sole analgesic for treatment procedure has to be tested. It's It is a thought that acupuncture ( Zhēn Jiǔ) may prove an indispensible supplement to conventional treatment modalities and more of clinical trials and studies are required to prove the efficacy. Acupuncture ( Zhēn Jiǔ) is not a miracle cure and is not going to replace the drill. However, the technique can be a supplement to conventional treatments in TMDs, facial pain, pain management Sjoegrens syndrome, and in phobias and anxiety. The application and use of Acupuncture ( Zhēn Jiǔ) comes with some side effects. Proper training needs to be obtained before commencement of any procedure related to acupuncture ( Zhēn Jiǔ). Various training programs are offered to train clinical practitioners the apt method to use acupuncture ( Zhēn Jiǔ).

Demystifying acupuncture

Acupuncture refers to the insertion of fine needles into the body at specific points for a therapeutic effect. The term comes from the Latin words 'acus' (needle) and 'punctura' (to puncture). The technique has been practiced in the Far East for at least 3000 yrs but it is only in the last 30 yrs that interest has developed in the West underpinned by increasing scientific research. One of the main uses of acupuncture has been to treat musculoskeletal pain and this article will review the evidence base and outline the main theories of mechanisms of action.

Introduction to acupuncture in dentistry

An introduction to the practical application of acupuncture in dentistry is presented in the light of current research. It is concluded that acupuncture could supplement conventional treatment modalities. Its value in the treatment of temporomandibular dysfunction syndrome and facial pain has been well documented and supported by randomised controlled trials. Although it may be useful in the control of post-operative pain, its use as sole analgesia for operative care is questionable. The mode of action of acupuncture can be explained with reference to modern neurophysiology. A short training course can allow the technique to be an effective tool in every dentist's hands.

Pressure on acupoints decreases postoperative pain

Our objective was to study the analgesic effect of acupoint pressure on postoperative pain in a controlled single-blind study. Forty patients undergoing knee arthroscopy in an ambulatory surgery unit in a university-affiliated hospital were randomized to receive either an active stimulation (AS) or a placebo stimulation (PS) 30 min after awakening from anesthesia. We stimulated 15 classical acupoints in the AS group, on the side contralateral to surgery, with a firm pressure and a gliding movement across the acupoint. In the PS group, 15 nonacupoints were subjected to light pressure in the same areas as the acupoints in the AS group. We assessed pain using a 100-mm visual analog scale (VAS) before sensory stimulation, after 30 and 60 min, and after 24 h. We recorded heart rate, systolic arterial pressure, and skin temperature before stimulation and after 30 and 60 min. We assessed skin blood flow with laser Doppler before stimulation and after 1 and 30 min. Sixty minutes and 24 h after AS, VAS pain scores were lower than in the placebo group (p < 0.05 and 0.0001, respectively). There were no significant changes in the autonomic variables. The results indicate that pressure on acupoints can decrease postoperative pain.

The effect of chest wall transcutaneous electrical nerve stimulation on dyspnoea

We studied the effects of transcutaneous electrical nerve stimulation (TENS) over the chest wall on breathlessness in normal subjects during exercise. Eleven male subjects performed a progressive incremental exercise test to break point on four consecutive days. TENS (continuous form, frequency 100 Hz, pulse width 200 microseconds) was applied during three of these tests-over the second intercostal spaces during inspiration ('in phase' with the underlying inspiratory muscle contraction) or expiration ('out of phase' with contraction) or over the deltoid muscles during inspiration (control), and not on the fourth occasion in random order. Breathlessness (Borg scale), heart rate, respiratory frequency, tidal volume, minute ventilation and minute oxygen uptake were measured. No significant differences were found for any of the measured variables between the four study days. We conclude that TENS under these circumstances has no effect on the sensation of breathlessness or on the measured physiological variables in normal subjects during exercise.

Analgesic effects induced by TENS and electroacupuncture with different types of stimulating electrodes on deep tissues in human subjects

Effects of conditioning peripheral nerve stimulation with different types of stimulating electrodes on pain thresholds in various deep tissues were measured in human subjects. Cone-shaped metal (phi 13 mm), rubber (phi 13 mm), and large soft surface electrodes (50 x 150 mm) were used for transcutaneous electrical nerve stimulation (TENS), and insulated and non-insulated acupuncture needles (diameter: 240 microns) were used for electroacupuncture (EA). Two pairs of electrodes were placed around the point of deep pain measurement. Symmetrical positive and negative square pulses (0.1 msec at 100 Hz) of just below the pain tolerance intensity were used for both TENS and EA. Deep pain thresholds were measured at the center of the thigh with a pulse algometer and insulated needle electrodes. Pain thresholds of deep tissues were in the order periosteum < fascia < skin (including subcutaneous tissues) < muscle. TENS with surface electrodes significantly increased pain thresholds of skin and fascia but not those of muscle or periosteum. The shape, material and size of the surface electrodes hardly affected the degree of analgesic effect, except in the fascia by large soft electrodes. In contrast, EA with non-insulated needles induced a greater increase in pain threshold in skin, fascia and muscle, although statistically significant results were obtained in only the first two tissues. EA with insulated needle electrodes was the only technique with which we obtained a significant increase in pain threshold in muscle and periosteum. These results suggest that the choice of electrode and stimulus parameters is important for the production of sufficient analgesic effects in different somatic tissues and that insulated needle electrodes are useful for pain relief in deeper tissues such as muscle and periosteum.

Acupuncture as a Therapy

Eighty consecutive patients, with good experience of acupuncture, were questioned about their clinical response to acupuncture. This is classified as immediate, intermediate and therapeutic. The long term therapeutic response was delayed in onset by 3 or more days in 50% of the patients. Most scientific study concentrates on the immediate reactions, so this delay in the therapeutic response is not generally recognised, understood or investigated, nor are the occasional adverse reactions (15% in this study) occuring during the intermediate stage. The response in the immediate and intermediate stages may not be related to the longer term therapeutic effect.