Photobiomodulation therapy in dogs undergoing TPLO after cranial cruciate ligament rupture shows promise but no statistically significant difference in a randomized trial

OBJECTIVE

Effect of photobiomodulation therapy (PBMT) in patients with CCLR after TPLO surgery by measuring C-reactive protein (CRP), percentage weight bearing, lameness using a short form of a composite measure pain scale, evaluated by the clinician and owners, and surgical site infection.

SAMPLE

54 client-owned dogs with CCLR undergoing unilateral TPLO surgery were enrolled in this study between April 5, 2021, through April 10, 2022.

METHODS

The study population was randomly assigned to either a treatment group receiving PMBT (24 dogs) or a control group (30 dogs). PMBT was performed on the treatment group immediately after induction, and 6 hours, 24 hours, 48 hours, and 8 weeks postoperatively. The control group received sham PMBT (device turned off) at the same time. Evaluation of CRP, CMPS-SF, evidence of SSI, and %WB were evaluated for all dogs 24 hours preoperatively, and then 24 hours, 48 hours, and 8 weeks postoperatively. Owners completed CMPS-SF and subjective evaluations weekly for 8 weeks postoperatively.

RESULTS

No statistically significant differences were found between treatment groups when evaluating CRP, %WB, and CMPS-SF by the clinician and weekly evaluation of the CMPS-SF by owners. Although no statistically significant differences were found in patients developing surgical site infections between treatment groups, SSI was only observed in patients in the control group (5/30, 16.6%). Most were minor/superficial infections (4/30 13.3%), and a single dog (1/30, 3.3%) had a major/deep surgical site infection.

CLINICAL RELEVANCE

Although with promising but not statistically significant differences between groups, surgical site infections may be reduced after PBMT application.

The Effect of Photobiomodulation Therapy on Inflammation Following Dental Prophylaxis

To evaluate the effectiveness of photobiomodulation therapy (PBMT) in reducing gingivitis following professional dental prophylaxis in dogs in a prospective, randomly controlled, double-blind study. The study included 47 dogs (male n = 23, female n = 24), with a mean age of 6.5 ± 2.6 years and a bodyweight of 28.9 ± 5.3 kg. Breeds included: Belgian Malinois Shepherd Dogs (n = 23), German Shepherd Dogs (n = 14), Labrador Retriever (n = 4), and Dutch Shepherd Dogs (n = 3). The left side of the mouth was treated by performing dental prophylaxis (control group). The right side received dental prophylaxis and a single session of PBMT using a Class IV therapeutic laser (treatment group). Each side was graded individually for periodontal disease (PD), gingivitis, and calculus. Follow-up observations were conducted on days 1, 3, 8, and 15 post-treatment. Results were compared using a Mann-Whitney Test. Multiple regression was run to predict PD, gingivitis, and calculus scores using age, sex, and breed. A p < .05 was considered significant. The PBMT group (PG) showed significantly lower gingivitis scores from day 1 to 15 post-treatment. PD had an increasing prevalence with age. Age and breed contributed to the prediction of PD, gingivitis, and calculus grading. This study showed that PBMT significantly reduced the grade of gingivitis following dental prophylaxis, and may be a useful adjuvant procedure following dental prophylaxis.

Photobiomodulation (Therapeutic Lasers): An Update and Review of Current Literature

Photobiomodulation therapy, also commonly known as laser therapy, continues to grow in popularity in veterinary medicine. It is the use of red and near-infrared light to simulate healing, relieve pain, and reduce inflammation. The potential variety of conditions for which it can be used as an adjunctive, non-invasive modality has propelled its use in both veterinary rehabilitation, sports medicine, and general practice. In the last decade, clinical research has grown with increasing evidence for efficacy for some conditions but mixed to limited in others and many conditions not represented.

Transcranial photobiomodulation (laser) therapy for cognitive impairment: a review of molecular mechanisms and potential application to canine cognitive dysfunction (CCD)

Alzheimer’s disease (AD) is a common degenerative brain disorder of aging people which shares many clinical and pathological features with canine cognitive dysfunction (CCD). CCD is considered a naturally occurring model of human AD. Transcranial photobiomodulation therapy (tPBMT), also known as transcranial laser therapy, entails delivering photons of near infrared to infrared light from the skin surface of the scalp to the underlying brain. Specific molecular cellular receptors, called chromophores, absorb this energy, and use it to initiate biological reactions with potential therapeutic benefit. Improvement in cognitive ability using tPBMT has been documented in rodent AD models and human clinical trials. The purposes of this review are to provide an overview of the suspected molecular mechanisms of action of tPBMT for the treatment of cognitive decline and to propose potential application of this treatment modality for dogs affected by CCD.

Perilesional photobiomodulation therapy and physical rehabilitation in post-operative recovery of dogs surgically treated for thoracolumbar disk extrusion

BACKGROUND

Recent studies have reported contrasting results of the effects of laser therapy on post-operative intervertebral disk herniation, with a lack of evidence-based advantages of this modality within a rehabilitation protocol. The aim of this study was to report the clinical effects of photobiomodulation therapy within a post-operative rehabilitation protocol in dogs submitted to surgery for thoracolumbar disk extrusion. Twenty-four dogs were included in the study (12 dogs treated with laser therapy and rehabilitation protocol and 12 dogs treated with same rehabilitation protocol but without laser therapy).

RESULTS

All dogs treated with laser therapy showed improved neurological status (Modified Frankel Score more than 3 within 30 days of physiotherapy starting) if deep nociception on admission was maintained (P = 0.04). However, Kaplan-Meier analysis did not show any statistical difference in time to regain ambulatory ability, although there was a tendency for a shorter mean time of 14.2 ± 8.55 days in the laser group versus 24 ± 18.49 days in the no laser group.

CONCLUSIONS

The use of laser therapy in the post-operative rehabilitation of dogs affected by intervertebral disc extrusion and submitted to surgery for spinal decompression could help improve their neurological status.

Effects of laser power, wavelength, coat length, and coat color on tissue penetration using photobiomodulation in healthy dogs

Photobiomodulation is an accepted regenerative medicine treatment modality used to stimulate tissue repair, mediate inflammation, and improve mobility in humans and animals. The objective of this study was to assess the influence of laser power and wavelength, coat length and color, and shaving on in-vivo photon delivery by therapeutic laser in dogs. Forty-seven dogs of various breeds and coat colors (17 black, 15 brown, and 15 white) and with varying coat lengths were assessed with 2 commercially available veterinary lasers. Photons were delivered to the lateral aspect of the inguinal fold and calcaneal tendon, with direct penetration through the dermis, as well as dermis and tendon, as measured with a thermopile laser sensor. Significant impacts on laser transmission were noted for laser power (P = 0.001), wavelength (P < 0.002), coat color (P < 0.001), and shaved coat (P < 0.001). Percent transmission was higher for a class IV 810/980 nm wavelength laser at 0.5 W than for a class IIIb 904 nm laser (P < 0.001). There was a significant difference between transmission of photons among white, brown, and black coats, with less transmission noted with increasing coat pigment (P < 0.001). Transmission was greater at higher power levels (3 W, 5 W) Results showed significant differences in laser transmission for all variables assessed, with the exception of coat length, which was not a significant predictor of laser transmission. As transmission was significantly reduced in darker and unshaved areas, higher power lasers may be necessary for darker pigmented dogs and shaving of hair is recommended before laser therapy.

Effects of Low-Level Laser Therapy and Chiropractic Care on Back Pain in Quarter Horses

Low-level laser therapy has been used clinically to treat musculoskeletal pain; however, there is limited evidence available to support its use in treating back pain in horses. The objective of this study was to evaluate the clinical effectiveness of low-level laser therapy and chiropractic care in treating thoracolumbar pain in competitive western performance horses. The subjects included 61 Quarter Horses actively involved in national western performance competitions judged to have back pain. A randomized, clinical trial was conducted by assigning affected horses to either laser therapy, chiropractic, or combined laser and chiropractic treatment groups. Outcome parameters included a visual analog scale (VAS) of perceived back pain and dysfunction and detailed spinal examinations evaluating pain, muscle tone, and stiffness. Mechanical nociceptive thresholds were measured along the dorsal trunk and values were compared before and after treatment. Repeated measures with post-hoc analysis were used to assess treatment group differences. Low-level laser therapy, as applied in this study, produced significant reductions in back pain, epaxial muscle hypertonicity, and trunk stiffness. Combined laser therapy and chiropractic care produced similar reductions, with additional significant decreases in the severity of epaxial muscle hypertonicity and trunk stiffness. Chiropractic treatment by itself did not produce any significant changes in back pain, muscle hypertonicity, or trunk stiffness; however, there were improvements in trunk and pelvic flexion reflexes. The combination of laser therapy and chiropractic care seemed to provide additive effects in treating back pain and trunk stiffness that were not present with chiropractic treatment alone. The results of this study support the concept that a multimodal approach of laser therapy and chiropractic care is beneficial in treating back pain in horses involved in active competition.

Penetration Profiles of a Class IV Therapeutic Laser and a Photobiomodulation Therapy Device in Equine Skin

Photobiomodulation therapy (PBMT) effects depend on the energy settings and laser penetration. We investigated the penetration time profiles of two different light therapy devices, at the dark and light skin regions in horses. Six light skin and six dark skin adult clinically healthy Arab and Quarter horses were used. A cutometer was used to measure the width of the skin fold from both sides of the cervical area, followed by three measurements of the thickness of the same skin fold by transversal and longitudinal ultrasonography (US). The depth of light penetration was compared based on the percentage of penetration versus power, between a portable PBMT device versus a class IV laser device. The laser mean power output was measured with an optical power meter system for 120 seconds after penetrating the skin. Skin width and laser penetration were compared among equipment by paired "t" test. There was no difference in the width of the skin fold between measurements acquired by the cutometer against either longitudinal or transversal US or between the US measurements at cervical versus metacarpus area. Light penetration was greater in both kinds of skins in the PBMT (0.01303 ± 0.00778) versus class IV laser (0.00122 ± SD 0.00070) (P < .001). The PBMT device provided a greater energy penetration than the class IV laser in unclipped light and dark skin, suggesting that the former may produce a better therapeutic effect. The color of the skin changes penetration profiles of PBMT.

A randomized blind placebo-controlled trial investigating the effects of photobiomodulation therapy (PBMT) on canine elbow osteoarthritis

The effect of photobiomodulation therapy (PBMT) or sham light therapy on pain, nonsteroidal anti-inflammatory drug (NSAID) requirement, and lameness was studied in 20 dogs with naturally occurring elbow osteoarthritis. Dogs (n = 20) were randomly assigned to receive either PBMT (group PBMT; n = 11) 10 to 20 J/cm² or a placebo treatment (sham light group S; n = 9) treatment 0 J/cm², to both elbows for 6 weeks. Lameness score, pain score, and NSAID dose were recorded by blinded study personnel before and 7 to 10 days after last treatment. Reduction in NSAID dose occurred in 9/11 dogs in the PBMT group, and in 0/9 of group S dogs (P = 0.0003). There was greater improvement in lameness score post PMBT versus S therapy (P = 0.001). A greater reduction in pain score was detected in 9/11 parameters in group PBMT (P < 0.05). Regularly scheduled PBMT at 10 to 20 J/cm² per joint for 6 weeks was successful in improving lameness and pain scores, and in lowering NSAID requirement in canine elbow osteoarthritis patients.

Gross and histologic evaluation of effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product on experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana)

OBJECTIVE To assess effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product for the treatment of experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana). ANIMALS 16 healthy subadult green iguanas. PROCEDURES Iguanas were anesthetized, and three 5-mm cutaneous biopsy specimens were obtained from each iguana (day 0). Iguanas were randomly assigned to 2 treatment groups, each of which had a control treatment. Wounds in the topical treatment group received silver sulfadiazine, a topical antimicrobial product, or no treatment. Wounds in the laser treatment group received treatment with a class 4 laser at 5 or 10 J/cm² or no treatment. Wound measurements were obtained daily for 14 days. Iguanas were euthanized, and treatment sites were evaluated microscopically to detect ulceration, bacterial contamination, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity. RESULTS On day 14, wounds treated with a laser at 10 J/cm² were significantly smaller than those treated with silver sulfadiazine, but there were no other significant differences among treatments. Histologically, there were no significant differences in ulceration, bacterial infection, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments. CONCLUSIONS AND CLINICAL RELEVANCE Photobiomodulation at 10 J/cm² appeared to be a safe treatment that was tolerated well by green iguanas, but it did not result in substantial improvement in histologic evidence of wound healing, compared with results for other treatments or no treatment.

Preliminary evaluation of the effects of photobiomodulation therapy and physical rehabilitation on early postoperative recovery of dogs undergoing hemilaminectomy for treatment of thoracolumbar intervertebral disk disease

OBJECTIVE To evaluate the effects of postoperative photobiomodulation therapy and physical rehabilitation on early recovery variables for dogs after hemilaminectomy for treatment of intervertebral disk disease. ANIMALS 32 nonambulatory client-owned dogs. PROCEDURES Dogs received standard postoperative care with photobiomodulation therapy (n = 11), physical rehabilitation with sham photobiomodulation treatment (11), or sham photobiomodulation treatment only (10) after surgery. Neurologic status at admission, diagnostic and surgical variables, duration of postoperative IV analgesic administration, and recovery grades (over 10 days after surgery) were assessed. Time to reach recovery grades B (able to support weight with some help), C (initial limb movements present), and D (ambulatory [≥ 3 steps unassisted]) was compared among groups. Factors associated with ability to ambulate on day 10 or at last follow-up were assessed. RESULTS Time to reach recovery grades B, C, and D and duration of postoperative IV opioid administration did not differ among groups. Neurologic score at admission and surgeon experience were negatively associated with the dogs' ability to ambulate on day 10. The number of disk herniations identified by diagnostic imaging before surgery was negatively associated with ambulatory status at last follow-up. No other significant associations and no adverse treatment-related events were identified. CONCLUSIONS AND CLINICAL RELEVANCE This study found no difference in recovery-related variables among dogs that received photobiomodulation therapy, physical rehabilitation with sham photobiomodulation treatment, or sham photobiomodulation treatment only. Larger studies are needed to better evaluate effects of these postoperative treatments on dogs treated surgically for intervertebral disk disease.

Emerging Modalities in Veterinary Rehabilitation

Many new modalities have been introduced in human and veterinary physical rehabilitation. In many instances, there is sound theory of how they may impact the physiology of various cells, tissues, or organs. This article reviews some of the modalities that have been introduced recently in human and veterinary rehabilitation. Topics include low-level laser, phototherapy, and extracorporeal shock wave treatment.