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Case 36a
by
Professor Chua Chung Nen & Dr. Ngo Chek Tung
A 12 year-old
boy fell at home against the wall where a fishhook was hanging. The fishhook
entered the right upper eyelid (Figure 1) through the upper fornix
(Figure 2). The local doctor
attempted retrograde removal ie. removing the eyelid through its original
track but without success. He was given tetanus injection and referred to
our eye department. Examination showed normal vision in both eyes measuring
6/6 and the ocular movement was full which excluded extraocular muscles
involvement (Figure 3). The X-rays showed the possibility of frontal sinus
penetration by the point of the fish hook (Figure 4) and a
CT scan was ordered to better localize the position of the point. The reconstructed CT scans showed the
point of the
fishhook was extracranial and spare the frontal sinus (Figure 5).
Figure 5.
Reconstructed CT scans show the skull and frontal sinus were not penetrated
by the fishhook.
a. Why can't the
hook be removed by the retrograde method?
To understand why a fishhook can't be removed
by the retrograde method ie. along its entry site, one needs to understand
its structure (Figure 6).
Figure 6. Terminology of a fish hook.
The part of the hook that prevents
retrograde method is the barb which keeps the point embedded in the
fish’s mouth, and if the point is deep in the tissue as in our
patient retrograde removal is difficult and may cause serious damage to
adjacent structures.
b. How may the
fishhook be removed?
There are two methods1
suitable for removing the fish hook in this case (See Figure 7):
a. Method 1: The
advance and cut method. In this method, the hook is advanced through the
skin and the barb is then cut off. The remaining hook is backed through
the entry wound. This method is best for hook with a single barb.
b. Method 2: The cut
and advance method. The eye of the fish hook is cut off and the
remaining hook is pulled through the skin by advancing the point of the
hook. This method is especially suitable by hook with multiple barbs.
Although the fishhook in our patient has a
single barb, we chose method 2 over method 1 because the position of the
hook is such that if we were to advance it the shank will press on the
globe and additional pressure transmitted during cutting of the barb may
damage the globe.
The fishhook in this case was thick and
several cutting instruments were used before we eventually cut off the
eye using a large size bone cutter borrowed from the orthopaedic theatre
(Figure 8). A suprabrow skin incision was made near the point of the
hook and the hook was advanced through the skin (Figure 9). A lid
guard was inserted between the shank and the globe to protect the eye
during removal of the hook (Note: This is an important
step to avoid accidental globe perforation by the hook. Figure
10). The hook was removed by grasping the point using a pair of
artery forceps and pulled through the skin incision. All the procedures
were performed using topical ocular anaesthesia and skin and fornix
infiltration with 1% lignocaine. Apart from some postoperative eyelid
swelling, the patient recovered well (Figure 11).
Figure 8. Several cutting instruments were
tried before a large size bone cutter succeeded in
removing the eye of the hook.
Figure 9. An incision was made near the
point of the hook. The hook was then advanced through
the incision.
Figure 10. A lid guard was inserted to
protect the globe before the hook was removed by grasping
the point with a pair of artery forceps.
Figure 11. Post-operative lid swelling and
the offending hook.
An alternative method of removal was
described by Ma and Lin2: The tip of the hook is advanced
through the anaesthetised skin to expose the barb and the point. The
barb is cut off using the needle holder. The barbless hook is gently
withdrawn through the entry site (Figure 12). Because the barb is
smaller than the point or the eye, a smaller instrument and less force
is needed to cut the barb. Additionally, removing the hook through the
entry site rather than advancing the whole hook reduces tissue trauma.
Reference:
1. Gammons MG, Jackson E. Fishhook removal. Am
Fam Physician. 2001 Jun 1;63(11):2231-6.
2. Ma HP and Lin ACM. A simple method for removal of fish hooks in the
emergency department. Br. J. Sports Med. 2005;39;116-117.
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