Cryptorchidism in the horse - PowerPoint PPT Presentation

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Cryptorchidism in the horse

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the poor quality of some s (scanned in a hurry) ... good anaesthesia. Penis pulled forwards; inguinal and paramedian areas prepped. 9 ... – PowerPoint PPT presentation

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Title: Cryptorchidism in the horse


1
Cryptorchidism in the horse
  • Dr JE Cox
  • Division of Equine Studies

2
Cryptorchidism in horses
  • I apologise for
  • the poor quality of some slides (scanned in a
    hurry)
  • some pictures being missing (my set has got
    depleted over the years)
  • the possibility that this may be of absolutely
    no help to you in the forthcoming exam
  • BUT
  • Good luck

3
The phenomenon of cryptorchidism in horses
  • Temporary inguinal retention
  • Permanent inguinal retention
  • Incomplete abdominal retention
  • Complete abdominal retention

4
Inguinal retention
  • Temporary and permanent forms have same anatomy
    the testis has passed through the inguinal canal
    but has not descended to scrotum
  • Temporary form very common in ponies

5
Incomplete retention
  • Epididymal tail descended but testis still in
    abdomen

6
Complete retention
  • Testis and epididymal tail both in abdomen
  • Note that there is a small vaginal process and
    the remains of the gubernaculum (inguinal
    extension) through the inguinal canal

7
Abdominal retention
  • Note that complete retention is more common on
    the left whilst complete and incomplete retention
    are equally represented on the right side all
    to do with timing of descent of left and right
    testes

8
Positioning for cryptorchidectomy
Penis pulled forwards inguinal and paramedian
areas prepped
Dorsal recumbency good anaesthesia
9
Inguinal exploration
  • ALWAYS explore inguinal region surgically, even
    though you cannot feel anything
  • LOOK for scars though they only tell you
    someone has made a hole

10
Inguinal exploration
  • Cut through skin where the scrotum should be
    then DISCARD SCALPEL there are large veins down
    there (one shown here) so continue by blunt
    dissection

11
Inguinal exploration
  • You may find a stump with a muscle (the
    cremaster) on the outside open it carefully.
  • If you find, as here, blood vessels and the
    deferent duct, then it has been castrated (on
    that side at least)

12
Inguinal exploration
  • You may find a testis inside its vaginal tunic
    (as here)
  • Remove it and the animal has then been castrated
    on that side

13
Inguinal exploration
  • You may find a vaginal tunic which when you cut
    into it, you find epididymal tail (e), deferent
    duct (v) and body of epididymis (b) as here.
  • See next slide

14
Inguinal exploration
  • You may be able to deliver the testis by traction
    on the epididymal body

Anatomy slide shows why this works they are
attached to each other
15
Inguinal exploration
  • You may find inguinal extension of gubernaculum
    difficult to recognise as you may guess from
    this picture
  • This is a case of complete retention
  • See next slide

16
Inguinal exploration
  • You then be able to identify a small vaginal
    process and inside it a ligament traction on
    this may deliver the epididymal tail and then the
    testis

Anatomy slide shows why this works they are
attached to each other
17
Where now ?
  • The chart shows the options-
  • Invasive via inguinal canal are no longer
    recommended they have a high rate of
    post-operative prolapse of gut !!!

18
Where now ?
  • The chart shows the options
  • Non-invasive via inguinal canal (Adams) is also
    no longer used it was, in any case, based on a
    misunderstanding of the anatomy !!!!!

19
Where now ?
  • The chart shows the options
  • Non-invasive via inguinal canal (Inguinal
    extension) is the one described on slide 16

20
Where now ?
  • The chart shows the options
  • Invasive via body wall (flank) is no longer
    used it has no advantage over paramedian and is
    more difficult if both testes are in the abdomen.

21
Where now ?
  • The chart shows the options
  • Invasive via body wall (paramedian) was
    originally devised in the early 1800s (pre
    Lister, pre chloroform !) and then lost favour
    until re-discovered at Leahurst by Prof JG
    Wright in the late 1950s

22
Where now ?
  • The chart shows the options
  • Not shown is laparoscopic removal which is
    gaining favour

23
Paramedian
  • Paramedian incision parallel to opening of sheath
    and at that level too far back may be easier to
    get testis, but there is cod-fat to cut through
    too far forwards and it is difficult to
    exteriorise testis

24
Paramedian
  • Below fat lies tendon of external and internal
    oblique combined incise along length of incision

25
Paramedian
  • Below tendons of external and internal oblique
    combined lies straight abdominal muscle (also
    called rectus abdominis) split along fibres
    along length of incision

26
Paramedian
  • Below straight abdominal muscle lies tendon of
    transverse muscle, fibres at right angles to
    incision split along fibres at right angles to
    incision and puncture peritoneum below and enter
    peritoneal cavity.

27
Paramedian
  • Put your hand in
  • How are you going to find the testis working
    completely blind ?
  • It all follows from the anatomy shown at the
    beginning of this presentation
  • See next slides

28
Paramedian
  • Dissection of rig pig head to right and tail to
    left
  • Gut removed
  • Caudal abdomen exposed
  • Bladder (b) reflected caudally to expose cut end
    of rectum (r) at entrance to pelvic canal
  • See next slide

29
Paramedian
  • Dissection of rig pig head to right and tail to
    left
  • Note testis (t) and epididymal tail (e)
  • Note ligament ( proper ligament of testis)
    joining testis (t) to epididymal tail (e)

30
Paramedian
  • Note ligament going from epid tail into vaginal
    process
  • AND
  • Deferent duct going from epid tail to dorsal
    surface of bladder

31
Paramedian
  • If testis does not fall into your hand (most are
    soft and floppy), then find the deferent duct on
    dorsal surface of bladder, follow to epid tail
    and thence to testis
  • (By now you should know that these are connected
    to one another)

32
Paramedian
  • And pull out a plum !
  • Use emasculator for haemostasis (ligatures rarely
    required)

33
Paramedian
  • Repair transverse tendon and straight abdominal
    muscle in one layer as shown.
  • (there were some cracks in the glass of the slide
    hope you can work out what is crack and what is
    not)

34
Paramedian
  • Then, matress sutures in combined tendon of
    internal and external oblique.
  • Close dead space in fat.
  • Suture skin (all absorbable)

35
Dont forget !
  • Laparoscopic removal has been developed since I
    gave up doing any surgery
  • However, failure rate of paramedian, even in
    inexperienced hands, is probably less than for
    inguinal non-invasive and laparoscopic removal.
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