Page 41 - Veterinary Laser Therapy in Small Animal Practice

Analgesic effect 27

conventional drug therapy, but as a safe alternative, to trial of LT applied immediately after cholecystectomy
decrease the risk of drug abuse, especially opioid abuse, laparotomy wound closure showed a significant differ-
or drug toxicity, and LT is one of these options. [99] ence in pain rating scores and analgesic demand. [105]
In a systematic review of 16 randomized controlled Much more recently, a prospective, randomized, place-
trials including a total of 820 patients with neck pain bo-controlled clinical study reported an analgesic effect
treated with class III lasers, published in Lancet in of LT in the postoperative period after bariatric surgery.
2009, [100] both acute and especially chronic cases Laser was applied to the laparotomy incision area, with
improved, with an average improvement of 22 mm on a dose a bit higher than usual for wound healing, 10 J/
2
2
a 100 mm VAS, and this improvement persisted in the cm and 0.495 mW/cm , but with very good results. [106]
medium term (up to 3–6 months). This means that if Laser therapy could be a coadjutant of regional intra-
your pain score was 5 out of 10, and you had a typical operative anesthesia; in a double-blinded, placebo-con-
response, your pain would decrease to almost half of its trolled, randomized clinical trial involving 48 patients
intensity. Functional ability was also improved. Overall, undergoing radial fracture surgery, LT at the cervical
the evidence was categorized as moderate. Most of the nerve roots plus over the affected radius significantly
included studies were performed by treating trigger improved VAS values during and after the surgical pro-
points (average of 11 points per patient), delivering a cedure. [107]
wide range of doses, from less than 1 J/point to more We have already mentioned that chronic pain is
than 54 J/point. The most statistically significant dif- more challenging to treat, since a neuropathic compo-
ferences were observed with 2–6 J/point doses. Side nent can often develop in these patients. In fact, tra-
effects were similar to those in the placebo groups, ditional painkillers only work in about 30% of human
which points to another characteristic of LT that is very patients with neuropathic pain. This field has also
often reported: if properly performed, it is a very safe been researched in clinical trials with LT. One of them
procedure. included amputated human patients with refractory
The high safety of LT was also pointed out in another neuropathic pain and showed a positive and lasting
review of LT for lateral elbow tendinopathy (also analgesic effect of LT over a 4 month follow-up period.
known as tennis elbow), [101] which concluded that LT [108] However, the paper only included three patients,
is helpful in pain and disability relief for this condition. and should encourage a larger scale trial, since per-
Many of these patients initially had a poor prognosis, sistent pain at the stump (due to spontaneous nerve
due to long-term disease and failure of other treatment activity, which sensitizes the nervous system and leads
modalities, such as steroid injections. In this compila- to hyperalgesia and allodynia) is described in a high
tion of trials, the average improvement on a VAS was percentage of cases in humans, and thousands of ampu-
10.2–17.2 mm. A more intense analgesic effect was tations take place every year in both the human and
described in a review of LT for chronic joint disorders, veterinary fields. In this trial, doses ranged from 8 to 15
2
including knee, temporomandibular, or zygapophyseal J/cm over the amputation scar and patients received
joints: an average of 29.8 mm on a VAS scale, provided nine sessions. Another typical example of neuropathic
the trial used a high enough dose and included the joint pain in people is trigeminal neuralgia, and a review
capsule in the treated area. [102] on this topic concluded that LT should be considered
More recently, a meta-analysis of LT and pain for these patients. It also pointed out that the wider
including 22 clinical studies in humans described the the dose and treatment regimens considered, the less
efficacy of class III LT for pain relief in different con- consistent (yet still safe) the clinical effect becomes. [109]
ditions, such as arthritis, carpal tunnel syndrome, low Eventually, in 2016, a systematic review [110] identified
back pain, myofascial pain, or Raynaud’s syndrome. ten laboratory trials and five clinical trials regarding
The studies included varied treatment regimes, from neuropathic pain and concluded that LT had a posi-
2
0.9 to 30 J/cm , wavelengths from 637 to 957 nm, and tive effect on neuropathic pain management, although
most patients received 10 to 20 sessions. [103] again the wide variety of treatment regimens (e.g. doses
Most studies concerning the use of LT in acute sur- from 0.9 to 42 J/point) made it impossible to perform a
gical pain refer to dental procedures, and the results proper meta-analysis.
are varied. [35, 104] There are few studies concerning LT So, evidence supports the effectiveness of LT for
and soft tissue analgesia: an early double-blind clinical pain treatment, but in some fields the body of evidence

REDONDO PRINT (4-COL BLEED).indd 27 08/08/2019 09:47