Transcutaneous transmission of photobiomodulation light to the spinal canal of dog as measured from cadaver dogs using a multi-channel intra-spinal probe.

The target level photobiomodulation (PBM) irradiances along the thoracic to lumbar segment of the interior spinal canal in six cadaver dogs resulting from surface illumination at 980 nm were measured. Following a lateral hemi-laminectomy, a flexible probe fabricated on a plastic tubular substrate of 6.325 mm diameter incorporating nine miniature photodetectors was embedded in the thoracic to lumbar segment of the spinal canal. Intra-spinal irradiances at the nine photodetector sites, spanning an approximate 8 cm length caudal to T13, were measured for various applied powers of continuous wave (CW) surface illumination at 980 nm with a maximal power of 10 W corresponding to a surface irradiance of 3.14 W/cm2. The surface illumination conditions differed in skin transmission when the probe was off-contact with tissue and probe-skin contact when the skin was in place. For each condition of surface illumination, the beam was directed to respectively T13 (surface site 1), a spinal column site 4 cm caudal to T13 (surface site 5), and a spinal column site 8 cm caudal to T13 (surface site 9). Off-contact surface irradiation of 3.14 W/cm2 at surface sites 1, 5, and 9 transmitted respectively 234.0 ± 120.7 µW/cm2, 230.7 ± 178.3 µW/cm2, and 130.2 ± 169.6 µW/cm2 to the spinal canal without the skin, and respectively 35.7 ± 33.2 µW/cm2, 50.9 ± 75.3 µW/cm2, and 15.7 ± 16.3 µW/cm2 with the skin. Transmission with skin was as low as 12% of the transmission without the skin. On-contact surface irradiation of 3.14 W/cm2 at surface sites 1, 5, and 9 transmitted respectively 44.6 ± 43.1 µW/cm2, 85.4 ± 139.1 µW/cm2, and 22.0 ± 23.6 µW/cm2 to the spinal canal. On-contact application increased transmission by a maximum of 67% comparing to off-contact application. The information gathered highlights the need to clinically consider the impact of skin transmission and on-contact application technique when attempting to treat spinal cord disease with PBM.

Flexible nine-channel photodetector probe facilitated intraspinal multisite transcutaneous photobiomodulation therapy dosimetry in cadaver dogs.

Noninvasive photobiomodulation therapy (PBMT) of spinal cord disease remains speculative due to the lack of evidence for whether photobiomodulatory irradiances can be transcutaneously delivered to the spinal cord under a clinically acceptable PBMT surface irradiation protocol. We developed a flexible nine-channel photodetection probe for deployment within the spinal canal of a cadaver dog after hemilaminectomy to measure transcutaneously transmitted PBMT irradiance at nine sites over an eight-cm spinal canal length. The probe was built upon a 6.325-mm tubular stem, to the surface of which nine photodiodes were epoxied at approximately 1 cm apart. The photodiode has a form factor of 4.80 mm×2.10 mm×1.15 mm (length×width×height). Each photodiode was individually calibrated to deliver 1 V per 7.58 µW/cm2 continuous irradiance at 850 nm. The outputs of eight photodiodes were logged concurrently using a data acquisition module interfacing eight channels of differential analog signals, while the output of the ninth photodiode was measured by a precision multimeter. This flexible probe rendered simultaneous intraspinal (nine-site) measurements of transcutaneous PBMT irradiations at 980 nm in a pilot cadaver dog model. At a surface continuous irradiance of 3.14 W/cm2 applied off-contact between L1 and L2, intraspinal irradiances picked up by nine photodiodes had a maximum of 327.48 µW/cm2 without the skin and 5.68 µW/cm2 with the skin.

Long term outcome after laser assisted modified Forssell's in cribbing horses.

OBJECTIVE: To (1) report long-term outcome after laser assisted modified Forssell's procedure; (2) describe the prevalence of postoperative complications; and (3) identify risk factors associated with outcome. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n = 119). METHODS: Medical records (1994-2012) of horses that had laser assisted modified Forssell's procedure were reviewed. Signalment, preoperative duration of cribbing, postoperative complications and outcome were recorded. RESULTS: Follow-up was available for 90 horses; 76 had stopped cribbing for >1 year. Of 14 horses that resumed cribbing, median relapse time was 6 months. Preoperative cribbing duration was significantly associated with an increased probability of unsuccessful outcome when horses cribbed for >3 years before surgery (odds ratio of positive outcome: OR = 0.14, 95% CI: 0.02, 0.95). Overall, 22.2% horses had postoperative complications (hematoma, seroma, infection, and prolonged drainage). CONCLUSIONS: Laser assisted modified Forssell's is a very effective (84.4%) surgical treatment of cribbing behavior in horses. Preoperative cribbing duration was identified as a significant risk factor associated with unsuccessful surgical outcome.

Traumatic foot injuries in horses: surgical management.

Managing traumatic foot wounds in horses may require surgical intervention. These wounds include coronary-band and heel-bulb lacerations, septic pedal osteitis, septic navicular bursitis, sepsis of the collateral cartilages, and hoof-wall injuries. This article provides a practical overview of the surgical management of these types of wounds.

Musculoskeletal injury in thoroughbred racehorses: correlation of findings using multiple imaging modalities.

Adaptive and nonadaptive stress remodeling in Thoroughbred racehorses leads to most of their musculoskeletal injuries, and imaging plays an important role in its detection. Bone scintigraphy is important for detecting stress remodeling and stress fractures and aids in decision making when more than one lesion is present on MRI or radiographic examinations. MRI likely represents the best modality for the assessment of osteoarthritis of the metacarpophalangeal and metatarsophalangeal joints. Ultrasonography remains important as the first modality for the assessment of tendon and ligamentous injury. However, injury to the proximal suspensory and distal sesamoidean ligaments may be best diagnosed with MRI.

Effects of extracorporeal shock wave therapy on desmitis of the accessory ligament of the deep digital flexor tendon in the horse.

OBJECTIVE: To evaluate the effects of extracorporeal shock wave therapy (ESWT) on collagenase-induced lesions in the accessory ligament of the deep digital flexor tendon (ALDDFT) of horses. STUDY DESIGN: Paired, blinded controlled study. ANIMALS: Eight Thoroughbred horses (3 mares, 5 geldings; mean ± SD weight, 464 ± 26 kg, mean age, 8 ± 1.7 years). METHODS: Lesions were created in both ALDDFTs of all horses by injection of 2 × 10(3) IU of collagenase type I. Percent lesion and structure (fiber alignment and echogenicity) were quantified with ultrasonographic imaging 3, 6, and 9 weeks after collagenase injection. After ultrasound examinations, ESWT (1000 shocks at 0.15 mJ/mm2) was applied to 1 ALDDFT in each horse. ALDDFT were harvested 15 weeks after collagenase injection and the microstructure, mRNA levels of collagen types I and III, and collagen and glycosaminoglycan content were evaluated. RESULTS: There were no differences in percent lesion, echogenicity, or fiber alignment between control- and ESWT-treated ligaments at each evaluation time; however, compared with 3-week values, there was a significant increase in percent lesion and echogenicity for EWST treated ligaments at 6 weeks and significant decrease in both variables for treated and control ligaments at 12 weeks. Fiber alignment improved significantly at 9 weeks in controls and at 12 weeks in treated and control ligaments. Collagen type I mRNA levels were significantly higher in the ESWT treatment group compared with the control group 15 weeks after collagenase injection though differences in other mRNA levels, microstructure, and composition were not significant. CONCLUSIONS: Our results do not support an effect of ESWT on collagenase-induced lesions in the equine ALDDFT.

Compressive forces achieved in simulated equine third metacarpal bone lateral condylar fractures of varying fragment thickness with Acutrak Plus screw and 4.5 mm AO cortical screws.

OBJECTIVES: To compare compression pressure (CP) of 6.5 mm Acutrak Plus (AP) and 4.5 mm AO cortical screws (AO) when inserted in simulated lateral condylar fractures of equine 3rd metacarpal (MC3) bones. STUDY DESIGN: Paired in vitro biomechanical testing. SAMPLE POPULATION: Cadaveric equine MC3 bones (n=12 pair). METHODS: Complete lateral condylar osteotomies were created parallel to the midsagittal ridge at 20, 12, and 8 mm axial to the epicondylar fossa on different specimens grouped accordingly. Interfragmentary compression was measured using a pressure sensor placed in the fracture plane before screw placement for fracture fixation. CP was acquired and mean values of CP for each fixation method were compared between the 6.5 mm (AP) and 4.5 mm (AO) for each group using a paired t-test within each fracture fragment thickness group with statistical significance set at P<.05. RESULTS: AO screw configurations generated significantly greater compressive pressure compared with AP configurations. The ratio of mean CP for AP screws to AO screws at 20, 12, and 8 mm, were 21.6%, 26.2%, and 34.2%, respectively. CONCLUSION: Mean CP for AP screw fixations are weaker than those for AO screw fixations, most notably with the 20 mm fragments. The 12 and 8 mm groups have comparatively better compression characteristics than the 20 mm group; however, they are still significantly weaker than AO fixations. CLINICAL RELEVANCE: Given that the primary goals of surgical repair are to achieve rigid fixation, primary bone healing, and good articular alignment, based on these results, it is recommended that caution should be used when choosing the AP screw for repair of lateral condylar fractures, especially complete fractures. Because interfragmentary compression plays a factor in the overall stability of a repair, it is recommended for use only in patients with thin lateral condyle fracture fragments, as the compression tends to decrease with an increase in thickness.

Evaluation of a vessel-sealing device for laparoscopic granulosa cell tumor removal in standing mares.

OBJECTIVE: To describe a laparoscopic technique for granulosa cell tumor removal using a vessel sealing device (LigaSuretrade mark) in standing mares. STUDY DESIGN: Retrospective study. ANIMALS: Eight mares (8-24 years old; weighing, 406-525 kg). METHODS: Before surgery, ovarian size and adjacent body wall thickness was determined by ultrasonography. Mares were sedated and after local anesthesia (inverted L and local infiltration), laparoscopic cannulation was performed without insufflation. The mesovarium was anesthetized and the LigaSure instrument applied to the mesovarium for hemostasis and resection to remove the affected ovary. Mares were hospitalized for 24 hours before discharge. RESULTS: Median ovarian diameter was 10.5 cm (range, 6-14 cm). Median surgery time was 75 minutes (range, 40-180 minutes). Hemostasis was achieved using the LigaSure device in all mares. Median length of the abdominal wall incision made to remove the ovary was 13 cm (range, 5-17 cm); no incisional complications occurred. CONCLUSIONS: The LigaSure vessel sealing device provided adequate hemostasis for removal of larger neoplastic ovaries in standing mares. CLINICAL RELEVANCE: Concerns of ligature placement can be alleviated by use of the LigaSure device and standing laparoscopic technique provides excellent observation of the surgical field ensuring hemostasis.

Evaluation of cutaneous analgesia after non-focused extracorporeal shock wave application over the 3rd metacarpal bone in horses.

Extracorporeal shock wave therapy is becoming increasingly used in equine practice to treat musculoskeletal disorders. Although the exact effects of extracorporeal shock waves on tissues still need to be elucidated, transient cutaneous analgesia has been observed within treated areas in humans and horses. The purpose of this study was to determine the onset, magnitude, and duration of cutaneous analgesia after non-focused extracorporeal shock wave (ESW) application by comparing the limb withdrawal reflex latency (LWRL) in treated and untreated areas on the metacarpus of horses, using a focused light source. A single treatment with non-focused ESW was applied to 3 areas over the dorsal aspect of one metacarpus in 12 horses. The LWRL was measured to assess cutaneous sensation in treated and untreated control areas of the treated metacarpus and in an untreated area on the opposite metacarpus, before and at various time points after ESW application. Most treated and control areas revealed a significant decrease in LWRL over time compared with baseline values. Although the results of our study do not suggest cutaneous analgesia after ESW application to the equine metacarpus, we advise cautious use of this treatment modality for horses in training or before competition until further research is done.

Determination of functional and morphologic changes in palmar digital nerves after nonfocused extracorporeal shock wave treatment in horses.

OBJECTIVE: To determine functional and morphologic changes in palmar digital nerves after nonfocused extracorporeal shock wave (ESW) treatment in horses. ANIMALS: 6 horses. PROCEDURES: The medial and lateral palmar digital nerves of the left forelimb were treated with nonfocused ESWs. The medial palmar digital nerve of the right forelimb served as a nontreated control nerve. At 3, 7, and 35 days after treatment, respectively, 2 horses each were anesthetized and nerves were surgically exposed. Sensory nerve conduction velocities (SNCVs) of treated and control nerves were recorded, after which palmar digital neurectomies were performed. Morphologic changes in nerves were assessed via transmission electron microscopy. RESULTS: Significantly lower SNCV in treated medial and lateral nerves, compared with control nerves, was found 3 and 7 days after treatment. A significantly lower SNCV was detected in treated medial but not lateral nerves 35 days after treatment. Transmission electron microscopy of treated nerves revealed disruption of the myelin sheath with no evidence of damage to Schwann cell bodies or axons, 3, 7, and 35 days after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Nonfocused ESW treatment of the metacarpophalangeal area resulted in lower SNCV in palmar digital nerves. This effect likely contributes to the post-treatment analgesia observed in horses and may result in altered peripheral pain perception. Horses with preexisting lesions may be at greater risk of sustaining catastrophic injuries when exercised after treatment.

Evaluation of a vessel-sealing device for small intestinal resection and anastomosis in normal horses.

OBJECTIVES: To compare arterial bursting pressure after vessel closure using a vessel-sealing device (LigaSure Atlas Laparoscopic Sealer/Divider Instrument; Valleylab, Boulder, CO), a ligate-and-divide stapling device (LDS), and 2-0 polydioxanone suture. To evaluate the LigaSure Atlas as a method for ligation of the mesenteric vasculature during small intestinal resection in normal horses. STUDY DESIGN: Experimental study. ANIMALS: Part A: jejunal segments from 19 horses. Part B: 6 horses, aged 1 to 18 years, weighing 330 to 509 kg. METHODS: Part A: Jejunal segments with mesenteric vessels were collected from 19 horses. After closure by 1 of 3 methods (LigaSure Atlas, LDS, 2-0 polydioxanone) arteries were cannulated, and bursting pressure was measured by incrementally increasing intraluminal pressure until failure. Part B: Six horses had jejunal resection and anastomosis using a vessel-sealing device (LigaSure Atlas) to provide hemostasis of the mesenteric vasculature. Horses were monitored clinically for 4 weeks. RESULTS: Part A: Mean +/- SEM bursting pressure after 2-0 polydioxanone ligation (1,014.50 +/- 279.05 mm Hg) was significantly greater than mean bursting pressure after LigaSure (554.25 +/- 228.79 mm Hg), which was significantly greater than the mean bursting pressure after LDS (373.25 +/- 183.69). Part B: No major operative or postoperative hemorrhage occurred after application of the LigaSure Atlas for sealing and transecting mesenteric vasculature during small intestinal resection in normal horses. CONCLUSIONS: The LigaSure Atlas appears to be a safe method for hemostasis of the mesenteric vasculature during small intestinal resection in normal horses. CLINICAL RELEVANCE: Benefits of the LigaSure Atlas vessel-sealing device include reduced time required to provide hemostasis, acceptable arterial bursting pressure, no remaining foreign material, and no risk for ligature slippage. In our experience, use of the LigaSure Atlas during small intestinal resection and anastomosis in horses is safe for ligation of vessels less than or equal to 7-mm diameter.

Use of a dynamic compression plate and a cable cerclage system for repair of a fracture of the radius in a horse.

A pregnant 9-year-old Peruvian Paso mare was evaluated because of a fracture involving the left radius. On examination, grade IV/V lameness of the left forelimb was observed; radiography of the limb revealed a longitudinal oblique displaced fracture that extended from the caudal cortex of the radial mid-diaphysis into the humeroradial joint. To minimize the development of degenerative joint disease in the humeroradial joint, repair with internal fixation was recommended. A dynamic compression plate was applied to the cranial aspect of the radius; three 2-mm stainless steel cable cerclages were positioned around the mid- and proximal diaphysis. The horse was maintained in a sling for 8 to 12 hours daily for 3 weeks after surgery. Five months after surgery, the mare had foaled without complications, and grade I/V lameness during trotting only was observed. The combination of 1 dynamic compression plate and cable cerclage may provide satisfactory stabilization of this type of fracture in small to medium-sized horses.

Plasma and synovial fluid endothelin-1 and nitric oxide concentrations in horses with and without joint disease.

OBJECTIVE: To compare plasma and synovial fluid endothelin-1 (ET-1) and nitric oxide (NO) concentrations in clinically normal horses and horses with joint disease. ANIMALS: 36 horses with joint disease, and 15 horses without joint disease. PROCEDURE: Horses with joint disease were assigned to 1 of the 3 groups (ie, synovitis, degenerative joint disease [DJD], or joint sepsis groups) on the basis of findings on clinical and radiographic examination and synovial fluid analysis. Endothelin-1 and NO concentrations were measured in plasma from blood samples, collected from the jugular vein and ipsilateral cephalic or saphenous vein of the limb with an affected or unaffected joint, as well as in synovial fluid samples obtained via arthrocentesis from the involved joint. RESULTS: Plasma ET-1 concentrations between affected and unaffected groups were not significantly different. Median concentration and concentration range of ET-1 in synovial fluid obtained from the joint sepsis group (35.830 pg/mL, 7926 to 86.614 pg/mL; n = 7) were significantly greater than values from the synovitis (17.531 pg/mL, 0.01 to 46.908 pg/mL; 18), DJD (22.858 pg/mL, 0.01 to 49.990 pg/mL; 10), and unaffected (10.547 pg/mL, 0.01 to 35.927 pg/mL; 10) groups. Plasma and synovial fluid NO concentrations between affected and unaffected groups were not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: Endothelin-1 is locally synthesized in the joints of horses with various types of joint disease. Synovial fluid concentrations of ET-1 varied among horses with joint disease, with concentrations significantly higher in the synovial fluid of horses with joint sepsis. These results indicate that ET-1 may play a role in the pathophysiologic mechanism of joint disease in horses.

Nd:YAG laser-assisted modified Forssell's procedure for treatment of cribbing (crib-biting) in horses.

OBJECTIVE: To report an neodymium:yttrium-aluminum garnet (Nd:YAG) laser-assisted modified Forssell's surgical technique and outcome for treatment of cribbing (crib-biting) in horses. STUDY DESIGN: Retrospective clinical study. ANIMALS: Ten adult horses with stereotypic cribbing behavior. METHODS: Data were obtained from medical records and telephone conversations with owners, trainers, and veterinarians. Surgical technique involved an approximately 34-cm ventral median skin incision starting rostral to the larynx and extending caudally. A 10-cm section of the ventral branch of the spinal accessory nerve was removed, using an Nd:YAG laser at 25 W and continuous pulse with a contact, sculpted-fiber tip. After neurectomy, approximately 34-cm sections of the paired omohyoideus and sternothyrohyoideus muscles were removed starting 2 cm rostral to the ventral aspect of the larynx, at the basihyoid bone, using the Nd:YAG laser. RESULTS: Median horse age was 7 years (range, 1 to 11 years). Median surgical time was 90 minutes (range, 75 to 130 minutes). Long-term outcome (range, 7 to 72 months) was available for all horses. None of the horses had cribbing behavior after surgery, and all returned to their previous use. Four horses had complications (two of which were unrelated to the surgical site), but all recovered fully. CONCLUSION: The successful outcome we obtained is better than reported previously using a modified Forssell's technique. CLINICAL RELEVANCE: Surgical treatment for cribbing by Nd: YAG laser-assisted myectomy and neurectomy resulted in an excellent prognosis for resolution of the stereotypical behavior with minimal complications.