Cryptorchidism in the horse

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Cryptorchidism in the horse

• Dr JE Cox
• Division of Equine Studies

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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

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The phenomenon of cryptorchidism in horses

• Temporary inguinal retention
• Permanent inguinal retention
• Incomplete abdominal retention
• Complete abdominal retention

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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

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Incomplete retention

• Epididymal tail descended but testis still in
  abdomen

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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

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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 !!!

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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 !!!!!

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Where now ?

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

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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

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Where now ?

• The chart shows the options
• Not shown is laparoscopic removal which is
  gaining favour

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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

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Paramedian

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

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Paramedian

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

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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.

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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

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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

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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)

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Paramedian

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

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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)

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Paramedian

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

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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)

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Paramedian

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

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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.