1. بسم الله الرحمن الرحيم

2. وما أوتيتم من العلم إلا قليلا

3. Zaghloul I.E.A and Karrouf G.I.A.
Radiological Study on Normal and Long-Standing Laminitic Feet in Drafting Equine By
Zaghloul I.E.A and Karrouf G.I.A.
Dept. of Surgery, Anesthesiology & Radiology, Fac. of Vet. Medicine., Mansoura University.

4. The aim of this study on drafting equine is to provide a data-base against which different measurements could be compared, recording and evaluating the secondary radiological changes which accompanying the long standing cases of chronic laminitis affecting positively or negatively on selecting the strategies of management and comparing the gross anatomy of the sagittal sections of both normal and chronic laminitic feet in donkeys.

5. MATERIAL AND METHODS

6. Latero-medial radiographic projections were obtained from 40 clinically normal feet of 20 donkeys and 40 clinically normal feet of 20 drafting horses (3-72 months old). Those animals were admitted to the Veterinary Teaching hospital, Faculty of Veterinary Medicine, Mansoura University for treatment from medical problems rather than lameness. In addition, 28 feet of 12 donkeys (6-8 years old) clinically suffered degrees of chronic laminitis..

7. Three donkeys suffering incurable laminitis were euthanized and the affected feet were separated for radiographic study and sagittally sectioned for post mortem studies.
Three measures were adopted for recording the radiographic signs associated with chronic laminitis in draft donkeys as well as comparing of the gross anatomy of sagittal sections of both normal and affected feet were carried out

8. A) Measuring soft tissues thickness through the distance between the dorsal hoof wall and dorsal surface of the third phalanx .
B) Measuring the palmar cortical length of the distal phalanx, it extends from the dorsal tip of the third phalanx to the articular margin with the navicular bone.
C) Comparing the thickness of the soft tissues to the palmar cortical length of the distal phalanx, in order to avoid the effect of size of the animals and radiographic magnification

9. D) Normal angulation and plamar deviation of third phalanx: lines are drowning along the dorsal aspect of the hoof wall; using the metallic marker as a guide; and dorsal aspect of the third phalanx. Then a line is drawn parallel to the ground surface of the hoof to intersect these two lines, forming two angles 1,2. They are compared in normal and laminitic animals as in diagram (2). All radiographic measurements were done on the original radiographic films on a horizontal viewing box.

10. Angiography
Study was undertaken for studying the normal arteriogram of the normal foot as well as the laminitic one. While donkeys under the effect of deep narcosis using chloral hydrate 10% .

11. Postmortem examination : The affected and normal limbs of the euthanised donkeys were transected at the midmetacrpal/metatarsal regions and sectioned sagittally for comparative studies.

12. Diagram (1): Diagrammatic representation of the normal split foot Stippled area = coronary corium; hatching = laminar corium. The three phalangeal bones (P, M & D) are a straight line. The top of the pedal bone (e) for extensor process is slightly below the coronary band. The coronary corium is oval in shape; the solid dots represent the circumflex artery of the pedal bone (at the front) and blood vessels within the solar corium. Note that the frog extends in front of the area of attachment of the deep digital flexor tendon (t). (Eustace, 1992).

13. Diagram (2): Diagrammatic representation of the laminitic split foot stippled area = coronary corium; hatching = laminar corium. The three phalangeal bones (P, M & D) are not straight line. The top of the pedal bone (e)for extensor process is slightly below the coronary band. The coronary corium is oval in shape. The front of the pedal bone and of the hoof are not longer parallel. Difference between angel (1) and angel (2) is the degree of rotation (Eustace, 1992).

14. RESULTS

15. Radiographic signs and measurements of normal feet.
In donkeys, over two years of age, with normal feet, the wall thickness measure (11-14 mm), the palmar cortical length ranges between (33-35 mm), and the wall thickness/palmar cortical length ratio average (31-42%). Meanwhile these measurements in young donkeys less than 6 months were (9-11 mm), ( mm), and (28-39%), respectively as shown in (Fig.1).

16. Figure (1): Latero-medial radiograph of a normal donkey foot
Figure (1): Latero-medial radiograph of a normal donkey foot. The phalanges are in straight line and the wire marker is parallel to the front of the pedal bone. The wall thickness measures 12 mm and the palmar cortical length (PL) measures 35 mm.

17. In horses, over two years of age, the range of wall thickness measure (11-17 mm), the palmar cortical length thickness/palmar cortical length ratio was (57-70 mm), and the wall (16-29%). While in young foals, less than 6 months of age, the measurements were (9-12 mm), (40-55 mm), and (16-30 %) respectively as in (Figs. 2,3 ).
The recorded measurements of angle 1 and angle 2 in adult donkeys is between (48-55 degrees) and the difference range was from (0-4 degrees). In adult horses angle 1 and angle 2 measured (58-67 degrees) and the difference between angle 1 and angle 2 ranged (0-9 degrees).

18. Figure (2): Latero-medial radiograph of a normal foot in a drafting horse, the phalanges are in a straight line and the wire marker is parallel to the front of the pedal bone. The wall thickness measures 13 mm and the palmar cortical length (PL) measures 60 mm.

19. Figure (3): Latero-medial radiograph of a normal foot in three months old foal. The phalanges are in a straight line, the wire marker is parallel to the front of the pedal bone, the wall thickness measures 9 mm, and the palmar cortical length measure 45 mm.

20. Radiographic signs and measurements of long-standing laminitic feet in donkeys.
The predominant radiographic features of chronic laminitic cases were increase in wall thickness (18-28 mm) with lack of true rotation and distal displacement of the third phalanx in a number of 5 out of 28 feet (18%) as shown in (Fig. 4).

21. Figure (4): Lateral radiograph in chronic laminitic foot in a donkey showing chronic degenerative changes in os pedis. Notice increased width between the outer surface of the hoof and the dorsal cortical surface (Wall thickness=18 mm) without pedal rotation.

22. Distal displacement of the third phalanx, an increased the wall thickness and the ratio between the wall thickness and the palmar cortical length (46%). The dorsal surface of the hoof capsule and the dorsal cortex of the third phalanx remain parallel, marked moving of the extensor process of the third phalanx distally in relations to the coronary band which was marked at the end of the metallic wire in a number of 11 out of 28 feet (39.28 %), as shown in (Fig.5).

23. Figure (5): Lateral radiograph in chronic laminitic foot in a donkey showing distal displacement of the third phalanx without pedal rotation, and increased wall thickness/palmar cortical length ratio.

24. Decrease of normal bone density and focal region of bone destruction to the distal half of the third phalanx were seen in a number of 4 out of 28 feet (14.28 %) as in (Fig.6). Resorption of a part of the distal phalanx, and it is no longer visible (Fig.7). The tip of the third phalanx is curled up and it may be fuzzy and indistinct in 7 out of 28 feet (25 %) as in Fig.(8). Reverse rotation was reported in one foot only (3%).

25. Figure (6): Dorso-palmar and lateral radiographs showing chronic pedal ostitis, loss of normal bone density and focal region of bone destruction in a case of long-standing chronic laminitis in 6 years-old donkey (black arrows).

26. Figure (7): Dorso-palmar and lateral radiographs in long-standing case of laminitis in 6 years-old donkey showing mis-shapen of the hoof, osteoperosis of os pedis and the distal half of the distal phalanx is no longer visible.

27. Figure (8): Lateral radiograph in long-standing of chronic laminitis in 7 years old donkey showing flaring of the dorsal solar border of pedal bone. The tip of the pedal bone has a distinct appearance (curled up), black arrows.

28. The results of angiography in long standing laminitic cases revealed that both medial and lateral digital artery did not filled with contrast material, vessels of the coronary band became irregular. Central obliteration of the terminal arch and dorsal branches of the pedal bone were noticed .

29. Sagittal sections of normal and long-standing laminitic feet in donkeys.
In normal feet, the top of the extensor process of the distal phalanx measured 5 mm below the top of the dorsal hoof wall, the coronary groove is oval in shape, the dorsal cortex of the distal phalanx is closely parallel to the dorsal hoof wall, the horn tubules in the dorsal hoof wall run in straight lines down to the ground surface, the horny sole is concave (Fig. 10).

30. Figure (10): Sagittal section of a normal foot
Figure (10): Sagittal section of a normal foot. The coronary groove (a) is oval, phalanges are in straight line, dorsal cortex of pedal bone (b) is parallel to the dorsal hoof wall, horn tubules (c) run in straight line with concave horny sole and the tip of the extensor process of the distal phalanx (d) is 5 mm below the top of the dorsal hoof wall. a d b c

31. In long standing laminitic feet the top of the extensor process of the digital phalanx measure (10-11mm) below the top of the dorsal hoof wall, insensitive epidermal laminae and dermal sensitive laminae are easily separated by gentle traction and the third phalanx is only attached at the coronary band and digital cushion region. The horny sole is flat, hemorrhagic and congested laminae. The tip of the third phalanx was curled up, increased wall thickness and distal displacement of the third phalanx, with reverse rotation were recorded (Figs ).

32. a a c c b b d e
Figure (11-12): Sagittal sections in a chronic laminitic foot. The coronary groove (a) is not more oval, phalanges are not in typical straight line, and the horny sole (b) is flat. The laminae (c) are severely hemorrhagic and congested. The tip of the third phalanx (d) is curled up with clear distal displacement of the third phalanx (e).

33. Conclusion

34. The obtained data from the different measurements indicated that, the thickness of the wall and the palmar cortical length varied greatly between normal donkeys and horses within the same age group. Moreover, distal displacement of the third phalanx, increased the wall thickness and the ratio between the wall thickness and the palmar cortical length.

35. Decreased of normal bone density associated with fuzzy and indistinct appearance of the third phalanx were the prominent radiological signs of long standing cases of chronic laminitis. So, radiological parameters and secondary changes are the determinant factors for management and prognostic indicators of laminitis.

36. Thank you

37. Figure.(9): Angiographic appearance in a case of chronic laminitis showing that both medial and lateral digital artery did not filled with contrast material, obliteration of the terminal arch and rami of the third phalanx.

38. The extent of lamellar pathology lies hidden beneath the hoof wall, and one can only guess at what is real going on so the road of recovery after a serious bout of laminitis is a rocky one. Radiographs and the initial degree of pain expressed by the horse give valuable clues, and provide an adequate tool for quantitative assessment of the equine feet (Pollitt, 1999, and Kummer et al., 2004)

39. Introduction

40. The present study comprised 80 normal feet of 20 adult donkeys and horses (2– 5 years old) and 20 young donkeys and foals (3-6 months old). The four feet of those animals were clinically sound. Those animals were admitted to the Veterinary Teaching hospital, Faculty of Veterinary Medicine, Mansoura University for treatment from medical problems rather than lameness.

41. Addition, 28 feet of 12 donkeys (6-8 years old) clinically suffered degrees of chronic laminitis. The most prominent clinical features were depression of the dorsal coronary band, and concave front wall. Chronic wall rings, high heels, and flat sole were seen.

42. Radiographic Examination
The sole and wall of each hoof were cleaned. The horn in the dorsal part of the hoof wall just below the coronary band was rasped smooth and any flaking horn trimmed away, and creates a flat dorsal surface. Straight stiff wire marker of known length is taped to the dorsal hoof wall with the top of the wire where the wall starts. All feet were radiographed whilst bearing weight with the limbs in normal position as possible which were raised on a flat wooden block

43. Laminitis can results in radiographic signs of rotation of the third phalanx and this problem produces little diagnostic challenges to most equine practitioners. While the radiographic signs of secondary changes as loss of normal bone density, prominent hypervascularity, focal region of destruction, increased thickness of soft tissues and sometimes sequestration is the real challenges (Stick, et al., 1982).