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 Abstract
Major vascular injury during lumbar discectomy
is a rare complication of one of the
commonest surgical procedures performed in
the Neurosurgical unit.
Its occurrence may be associated with high
morbidity and mortality, particularly if
it is not diagnosed at an early
stage.
We illustrate, in our case, the early
manifestations of the injury and the
associated hypovolemic shock. In addition,
we describe the management approach and
the mechanism of this injury.
Other types of injuries will be referred to
during the discussion of this case.
Patient Report
A 38-year-old male, weighing 63 Kg with
hemoglobin level of 16.1 gm/L and ASA I,
was scheduled for L5/S1 microdiscectomy.
Anesthesia was induced with Propofol 150 mg,
Fentanyl 250 µg and Pancuronium 8 mg.
The patient was intubated and was then
turned into prone position on Wilson's
frame, and anesthesia was maintained by
O2/Air and Isoflurane with continuous
infusion of Remifentanil.
After four hours of surgery, the surgeon noticed
excessive bleeding from the surgical site
associated with a drop in the blood
pressure to 85/43, which responded to an
immediate fluid transfusion. One
hour later, there was another severe drop
of blood pressure to 57/30 and tachycardia
of 114/ min, which were reasonably
corrected with an infusion of crystalloids
and colloids. Here we suspected the
possibility of vascular injury, as the
volume of blood loss from the operation
site did not match with the hypotensive
episodes that the patient had. At the end
of surgery and on turning the patient into
the supine position, the patient was
hemodynamically unstable; in addition, the
patient showed a localized swelling on the
left side of the abdomen.
The vascular surgeon was called upon
urgently. During that period central
venous catheter, arterial line, Foley
catheter and nasogastric tube were all
inserted. A Cell saver and a Level 1
System Pressure Infuser were
requested. Meanwhile, we decided to
reduce the fluid resuscitation until the
surgeon was able to secure the
bleeder. A longitudinal abdominal
mid line incision was performed, then
posterior peritoneal dissection of the
infra renal part of the aorta, and both
common iliac arteries, revealed a
1.5 cm irregular tear that was
situated on the posterior wall of the
aorta and one cm above the
bifurcation. This was repaired using
Dacron mesh. The resuscitation
fluids included six units of each of the
following: Packed Red Cells, Fresh Frozen
plasma, Platelets concentrate,
Cryoprecipitate and a total of 9.5 L of
crystalloids and colloids.
Prior to the laparotomy the patient's laboratory
results were Hemoglobin 6.2 gm/L and a pH
of 7.072. In the immediate
postoperative period, the results were
Hemoglobin 14.2 gm/L and a pH 7.237.
Sodium Bicarbonate was not given.
Postoperatively, the patient was kept on the
ventilator, his hemodynamics were stable
as well as his renal profile. He was
extubated after a few days and discharged
from the hospital after 15 days without
obvious neurological deficit. However, on
interviewing him, he complained of lack of
concentration and loss of appetite.
Discussion
Symptomatic perforation of the anterior spinal ligament has
an overall incidence of 17 per 10,000
cases (1). The history of vascular injury
during disc surgery goes back to 1945 when
it was first reported by Linton and White
(2).
Since then, there have been many
other reports about this type of injury.
Vascular injury may involve the
left iliac artery, which is the most
common injury as it lies immediately
anterior to L4/5 disc space, the right
iliac artery, the aorta, the inferior vena
cava, the iliac veins and formation of
arteriovenous fistulae. Therefore, this
type of injury may be presented in various
ways such as hypovolemic shock (3, 4) or
heart failure (5).
There are other injuries recorded
during lumbar discectomy such as visceral
and ureteral (6, 7, 8). However,
major vascular injury remained the most
serious with a high percentage of
mortality.
Goodkin and
Laska (9) have collected 21 cases of
injuries during lumbar discectomy for the
period between 1985 and 1998 that
underwent litigation. However, the
real number of injuries were
imprecise. In their collection, only
18 of those cases were vascular
injuries. One third of the injured
were diagnosed in the operating room and
in 50 percent of those, the diagnoses were
delayed. The mortality rate was 33.3
percent. One third of the patients
with major vascular injury showed bleeding
into the disc space; other signs such as
abdominal distension and hypotension were
delayed.
Perforation of the anterior longitudinal ligament by may be performed by
either a Pituitary rongeur (fig 1),
forceps or a curette. This
perforation is usually the first sign
noticed by the surgeon in such cases.
There are many other predisposing factors to
this kind of injury such as peridiscal
fibrosis (10), previous intra-abdominal
surgery, and surgery for recurrent disc
herniation. The anatomical proximity
of the major vessels to the vertebral
bodies (fig 2) as well as other abdominal
structures are other factors that make
this type of injury possible.
There are several possible reasons behind the delay in the diagnosis of
some of these cases, some of which are:
a) the tamponade effect in the
prone position, which may keep a tear in a
vessel sealed (especially a venous tear)
until the patient is turned to the supine
position, b) the small surgical site,
especially in microdiscectomy, using an
operating microscope, and c) blood seeps
to the retroperitoneal area which may let
the injury go undetected by the surgeon.
High suspicion was practiced in this case, an additional large caliber
intravenous cannula was inserted and
extubation was delayed at the conclusion
of surgery until patient's condition was
verified. Pending securing the
injured vessel, we reduced the
resuscitation fluid to avoid raising the
blood pressure fearing ongoing bleeding.
Mattox et al.(11) have purported to show
that aggressive fluid resuscitation is not
beneficial in patients with truncal
penetrating trauma who are able to have
rapid operation.
However, there is no evidence from randomized controlled trials for or
against early volume of intravenous fluid
administration in uncontrolled hemorrhage
in prehospital settings (12).
Conclusion
Lumbar laminectomy and microdiscectomy are
common surgical procedures in Neuro and
Orthopedic units.
One major sign that should alert the
anesthesiologist to the possibility of
this injury is unexplained hypotension and
tachycardia. In young and healthy
patients, 30 to 40 percent of total blood
volume must be lost before signs of
hypovolemia arise.
Early detection of these major vascular injuries
is crucial in saving patients lives.
However, there are times when this type of
injury is diagnosed late, either in the
recovery room or even one day later (13,
14), therefore the nursing staff must be
aware of this possibility.
We think that Hydroxyethyl Starch (HES) was not a good choice for
resuscitation. Conditions where HES
should be used, with caution, are major
trauma and increased blood loss where a
possibility of coagulopathy due to HES may
lead to further blood and blood components
transfusion and therefore transfusion
risks (15).
References
Other
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