Keywords
craniotomy - hematoma - pseudoaneurysm - superficial temporal artery
Introduction
A superficial temporal artery (STA) pseudoaneurysm after a craniotomy is rare, with
only 16 cases reported in the literature—the majority of these were found in subcutaneous
pulsatile and painless masses.[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16] Herein, we report a case of an STA pseudoaneurysm with severe subcutaneous bleeding
after craniotomy, and provide a review of the literature. To our knowledge, only three
similar cases have been reported.[6]
[9]
[10]
Case History
A 47-year-old man with a history of hypertension was brought to the emergency department
of our hospital due to sudden onset of headache, right hemiparesis, and consciousness
disturbance (20 JCS: Japan Coma Scale).
On arrival, the head computed tomography (CT) scan showed a left subcortical hemorrhage
([Fig. 1A]). Craniotomy was performed on the same day.
Fig. 1 (A) Axial image of head computed tomography on admission. Intracranial hematoma was
detected in the left frontal lobe. (B, C) Photographs before the second surgery. Severe subcutaneous swelling was identified
in the left frontal region (▲). The superficial temporal artery (STA) was palpable
on the occipital side of the skin incision (—). A pulsative portion of the subcutaneous
mass was identified on the frontal side of the STA (△). A pulsatile portion of the
mass was identified on the frontal side of the STA.
For the first surgery, a coronal skin incision was made, and a right frontal craniotomy
was performed. A microscope was introduced to aid removal of the hematoma located
directly below the craniotomy. For skin closure, a 3–0 absorbent thread (Vicryl plus
3.0; Ethicon Co., Somerville, New Jersey, USA) was used subcutaneously, while a stapler
was used superficially. During the period from skin incision to closure, the left
STA was preserved posterior to the skin incision, and the surgery was completed without
damage to the STA.
The postoperative course was good, with mild paralysis of the right upper and lower
limbs and clear consciousness. Normal blood pressure was maintained by oral administration
of a calcium channel blocker. The surgical wound was in good condition, and the hooks
were removed on the 7th postoperative day. On the 20th day after surgery, the patient
noted pain and swelling of the wound, despite no prior reports of wound swelling.
The swelling gradually worsened within 1 hour, the sutures tore, and bleeding was
observed. An emergency head CT scan (plain and contrast) revealed a 13 × 21 × 22 mm
aneurysm in the parietal branch of the left STA with a marked subcutaneous hematoma
([Fig. 1B,C]). Because the patient experienced a severe headache, emergency surgery was performed.
There were no abnormal findings on preoperative blood tests, including blood coagulation
and fibrinolysis function.
At surgery, the STA was palpable caudal to the prior skin incision ([Fig. 2A]). Additionally, a pulsating spot was observed on the frontal side of the STA within
the area of severe head swelling ([Fig. 2A,B]). This area was considered to be a pseudoaneurysm ([Fig. 2A]). The skin incision was extended caudally, and the STA was identified. During removal
of as much of the hematoma as possible, arterial bleeding was observed from the hematoma
area. Thus, the secured STA was temporarily blocked and the prior skin incision was
fully opened to sufficiently remove the hematoma. The STA was then traced distally,
and was found to be disrupted within the hematoma, with the distal end identified
nearby. Both ends were collected for pathology and ligated with silk thread.
Fig. 2 An axial (A) and coronal (B) view of gadolinium-enhanced computed tomography (CT) before the second surgery showing
a left subcutaneous hematoma (↓). A pool of contrast medium (⇩) was identified in
the hematoma, which was consistent with a pseudoaneurysm. (C) Three-dimensional CT angiography revealed a pool of contrast medium arising from
the left superficial temporal artery.
Pathology showed true blood vessels with elastic fibers ([Fig. 3A,B]). Membranous tissue with calcification consisting of some fibrous tissue was also
observed ([Fig. 3A,B]). The area was diagnosed as a pseudoaneurysm because elastic fibers were not identified.
Fig. 3 Histopathological examination of the surgical specimen. (A) Hematoxylin and eosin staining (×40 magnification). (B) Elastica van Gieson staining (×40 magnification). In the true vessel wall, internal
elastic fibers were identified by Elastica van Gieson staining (▲). The area of the
membranous tissue was diagnosed as a pseudoaneurysm because no elastic fibers were
identified (△).
After the second surgery, the patient's headache improved, and the hooks were removed
on the 7th day. There was no recurrence of subcutaneous swelling. The patient was
transferred to a rehabilitation hospital at 14 days after the second surgery.
Discussion
In head and neck aneurysms, the frequency of STA pseudoaneurysms was reported as 0.5
to 2.5%,[17] of which approximately 75% were caused by blunt head trauma.[18] This is because the STA runs just below the scalp, on top of the hard skull, making
it vulnerable to trauma.[17]
[18] Damage to the arterial wall can result in hematoma formation beneath the scalp,
while in some cases blood flow may remain between the hematoma cavity and the vessel
lumen. In this condition, the hematoma is absorbed and a fibrous coating develops
around it, forming a pseudoaneurysm.[17]
[18] Histological findings in our case showed evidence of true blood vessels and fibrous
tissue, without elastic fibers, in the excised area, which was consistent with a pseudoaneurysm.
Reports of pseudoaneurysms after craniotomy are rare, with only 16 cases in the literature
([Table 1]).[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16] Reported causes of STA damage include subcutaneous suture needles, hook retractor,
or three-point pin fixators.[6]
[7]
[8]
[13]
[16] Systemic diseases including hemophilia or vasculitis, and background such as triple
H therapy after subarachnoid hemorrhage, are also risk factors for pseudoaneurysms.[6]
[9]
[11]
[12] Furthermore, even if there is only endothelial damage without bleeding, surgical
manipulation or electrocoagulation may lead to formation of fusiform dilatation and
subsequent minor bleeding, resulting in pseudoaneurysm formation.[1]
[5]
[8]
[13] In our case, the STA was not injured during surgery and was clearly distant from
the site of the Mayfield 3-point pin fixator. Thus, the pseudoaneurysm in present
case may have resulted from microtrauma to the intima caused by surgical manipulation
or electrocautery.[1]
[3] Alternatively, the STA may have been injured during subcutaneous closure, resulting
in a small unnoticed bleed that caused the pseudoaneurysm.[1]
[5]
[8]
[13]
Table 1
Reported cases of pseudoaneurysm of the STA after craniotomy
|
Author
|
Sex
|
Age
|
Cause of craniotomy
|
Cause of STA injury
|
Duration (days)[a]
|
Rupture of pseudoaneurysm
|
Treatment
|
|
Shimoda et al (1988)[11]
|
Male
|
17 yo
|
Removal of intracranial hematoma
|
Unknown
|
40
|
No
|
Embolization
|
|
Fernández-Portales et al (1999)[4]
|
Male
|
51 yo
|
Clipping for ruptured aneurysm
|
Pin head holder
|
35
|
+
|
Extirpation
|
|
Tsutsumi et al (2000)[13]
|
Male
|
48 yo
|
Clipping for ruptured aneurysm
|
Possibly suture needle
|
40
|
No
|
Extirpation
|
|
Lee et al (2002)[8]
|
Male
|
52 yo
|
Clipping for ruptured aneurysm
|
Possibly suture needle
|
110
|
No
|
Extirpation
|
|
Hakan et al (2011)[5]
|
Female
|
58 yo
|
Clipping for ruptured aneurysm
|
Unknown
|
4 d
|
No
|
Extirpation
|
|
Bobinski et al (2004)[2]
|
Male
|
74 yo
|
Clipping for ruptured aneurysm
|
Unknown
|
17
|
No
|
Injection of thrombin glue
|
|
Wang et al (2011)[14]
|
Male
|
28 yo
|
Clipping for ruptured aneurysm
|
Possibly suture needle
|
25
|
No
|
Extirpation
|
|
Terterov et al (2012)[12]
|
Male
|
31 yo
|
Clipping for ruptured aneurysm
|
Possibly suture needle (triple H)
|
22
|
No
|
Coil embolization andsealed with liquid Onyx
|
|
Kobayashi et al (2013)[7]
|
Female
|
41 yo
|
Microvascular decompression
|
Pin head holder
|
71
|
No
|
Extirpation
|
|
Honda et al (2013)[6]
|
Male
|
57 yo
|
Clipping for ruptured aneurysm
|
Possibly suture needle (triple H)
|
1
|
+
|
Emergency surgery
|
|
Wright et al (2015)[15]
|
Male
|
78 yo
|
Removal of meningioma
|
Unknown
|
21
|
No
|
Coiling
|
|
Madhusudan et al (2015)[9]
|
Male
|
57 yo
|
Removal of high-grade glioma
|
Possibly suture needle (vasculitis)
|
8
|
+
|
Emergency surgery
|
|
Anania et al (2018)[1]
|
Unknown
|
3 wo
|
Surgery for craniosynostosis
|
Unknown
|
17
|
No
|
Extirpation
|
|
Entezami et al (2019)[3]
|
Male
|
83 yo
|
Removal of high-grade glioma
|
Unknown
|
Na
|
+
|
Embolized and surgery
|
|
Zheng et al (2021)[16]
|
Male
|
36 yo
|
Removal of epidural hematoma
|
Fish hook retractor
|
1
|
No
|
Extirpation
|
|
Shields et al (2021)[10]
|
Male
|
38 yo
|
Surgery for cerebrospinal fluid leak repair
|
Unknown
|
14
|
+
|
Emergency surgery
|
|
Present case
|
Male
|
47 yo
|
Removal of intracranial hematoma
|
Unknown
|
20
|
+
|
Emergency surgery
|
Abbreviations: STA, superficial temporal artery; wo, weeks old; yo, years old.
a The duration until the subcutaneous mass was identified after surgery.
The risk factors and probability of pseudoaneurysm rupture are unknown. Nevertheless,
massive bleeding was reported in 4 of 16 cases of pseudoaneurysm after craniotomy
(25%),[6]
[9]
[10] which is not uncommon. In these four cases of massive hemorrhage, including the
present case, no obvious pulsatile mass was observed prior to the pseudoaneurysm rupture.
However, this may be because careful monitoring for pseudoaneurysm formation was not
performed after the first surgery. Thus, careful monitoring of the wound after craniotomy
may allow for earlier and less invasive treatment.
Conclusion
Pseudoaneurysms of the STA after craniotomy may result in a severe subcutaneous hematoma
that requires surgical removal. After craniotomy, the patient should be carefully
monitored for the appearance of pseudoaneurysms in the surgical wound, even if there
is no intraoperative bleeding from the STA.
