Vol.2, No.9, 505-507 (2013) Case Reports in Clinical Medicine
Brain abscess from halo pin penetration
Rohit Patel, Bobby K. Desai*, T. James Gallagher
Department of Emergency Medicine, College of Medicine, University of Florida, Gainesville, USA;
*Corresponding Author: email@example.com
Received 9 October 2013; revised 7 November 2013; accepted 6 December 2013
Copyright © 2013 Rohit Patel et al. This is an open access article distributed under the Creative Commons Attribution License,
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Halo fixation devices are often employed for
critically ill or trauma patients with unstable cer-
vical pathologies. These include fractures, spi-
nal decompression and reconstruction proce-
dures. However, the critical care literature has
surprisingly little information in regard to asso-
ciated complications. Perry and Nickel pio-
neered the initial halo device in 1959 and soon
afterward recognized complications associated
with its use . They developed a detailed regi-
men to prevent abnormal pin placement and
infections. The details include pin placement in
“safe” zones, specific degrees of torque, and
techniques to minimize infection risk. Despite a
low death rate, a cerebral brain abscess often
leads to prolonged neurological morbidity .
Seizures and pneumocranium have also been
ascribed to intracranial penetration of halo pins
[3,4]. The following describes a patient with ce-
rebral abscess secondary to halo pin penetra-
tion. He then developed several other associ-
ated complications during hospitalization.
Keywords: Cerebral Abscess; Cranial Pin; Halo
Orthosis Device; Inner Tabl e of Skull; Complication
1.1. History and Presentation
A 50-year-old male presented to the University of
Florida emergency department (ED) with a history of
slurred speech and word finding difficulty. Two months
ago, his C2 fracture was stabilized with a halo device.
The injury resulted from an ATV accident. At the time of
initial discharge, he was neurologically intact. Loose
screws had required retightening in clinic five weeks
prior to this latest admission. Three weeks prior to arrival
in the ED, he had develop ed swelling of his face and p in
sites as well as purulent drainage around the pin sites.
This resolved with antibiotic treatment (amoxicillin-
clavulanate). One day prior to arrival, slurred speech and
word finding difficulty developed. The patient stated that
he awakened disoriented the night previous, noted
slurred speech, and had difficulty with specific words,
although he knew what he wanted to say. Two hours later,
he felt that the problems had resolved. However, he also
indicated that his handwriting looked like “gibberish”.
After phone consultation, he presented to the neurosur-
gery clinic. A diagnosis of cerebral infection was consid-
ered and the patient was sent to Emergency Department
for furthe r workup.
On examination, the patient was alert, awake, oriented,
and hemodynamically stable. Vital signs were within
normal limits. No abnormalities or localizing findings
were found on neurological examination. Speech was
completely intact. There was, however, erythema and a
small amount of purulent drainage from the pin sites. He
was afebrile and the white blood cell count (WBC) was
7000/cu mm. There were no signs of systemic infection.
1.3. Initial Treatment and Course
Head CT showed a new left parietal infarct and ade-
quate healing of the cervical spine fracture (Figure 1).
The halo was removed. Continued immobilization was
accomplished with a hard cervical collar. MRI & MRA
of the head and neck demonstrated meningitis, left fron-
tal cerebritis, and a left parietal intraparenchymal ab-
scess. The abscess appeared related to skull penetration
of the halo screws. Antibioitic treatment was initiated
with piperacilin-tazobactam. Surgical intervention was
planned (Figures 2(a) and (b)). Initial cultures were not
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K. C. Chou et al. / Natural Science 1 (2009) 505-507
Figure 1. CT brain without contrast. Ill defined area
of hypodensity in left parietal lobe with vasogenic
edema incompletely visualized due to halo device.
Figure 2. (a)-(b) MRI T1 pre and post contrast. Intracranial
infection with diffuse meningeal thickening and enhancement,
13 × 16 × 14 mm left parietal ring enhancing fluid collection
with adjacent vasogenic edema most consistent with abscess.
1.4. Hospital Course
Evacuation of the abscess was through a left frontal
and parietal craniotomy. Intra-op cultures grew a small
amount of MSSA. Two days postop, after being trans-
ferred to the floor, the patient experienced an un-wit-
nessed fall. Prior to the event, he had experienced in-
creasing confusion. A nurse went into room to check on
the patient and found him on the floor awakes but still
confused with his c-collar in place. An emergent CT scan
demonstrated a 6.5 × 4.5 cm hematoma within the pre-
vious left parietal operative bed. He was again returned
to the OR for hematoma evacuation (Figure 3). Postop,
his neurological status continued to improve. The Infec-
tious Disease service recommended a six-week course of
Cerebral abscess related to a halo screw represents a
rare complication and requires early recognition . To
date minimal information has appeared in the critical
care related literature. Halo devices have many advan-
tages. The halo effectively maintains spinal column
alignment. It can be easily applied and has minimal in-
terferences with mandibular function. Furthermore it pro-
vides earlier mobilization.
Garfin et al.  reviewed 179 cases to identify risks
with the external halo device and found that pin loosen-
ing occurred in 36% of patients, pin site infectio n in 20%,
severe pin discomfort in 18%, dysphagia in 2%, and
dural penetration in 1%.
A cerebral abscess can occur through improper pin
placement with penetration of the (inner table) due
topoor hygiene, or loosening or over-torqued cranial pins
. Saeed et al. described 16 cases of halo pin associated
cerebral abscess . The most common presenting symp-
tom was headache (8 cases), followed by fever (4 cases),
nausea/vomiting (3 cases), focal neurological deficits (2
cases), altered mental status (2 cases), and localized pain
(2 cases). The most common location of the abscess was
the parietotemporal area. S. aureus was isolated in 14 of
the 16 cases. The remaining cases showed S. epidermidis,
Peptococcus, or no organisms.
Penetration of the pins through the inner table of the
skull can create a direct route into the intracranial cavity.
Pins are constructed so that there is a sharp point and a
broader body to prevent such occurrence. However, it
may still occur particularly in an area of thin bone. “Safe”
zones have been recommended such as the posterolateral
aspects of the calvaria where the density of bone is
greater. This area corresponds to the 4 o’clock and 8
o’clock positions. The 12 o’clock position involves the
anterior calvaria or glabella and the 6 o’clock location
represents the posterior calvaria or posterior occipital
protuberance. Although the scar created by placement
Figure 3. CT without contrast after fall and evacuation (on
right). Large left parietal operative site hemorrhage and extra
axial blood collection with associated mass effect with herni-
ation and hydrocephalus.
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R. Patel et al. / Case Reports in Clinical Medicine 2 (2013) 505-507
Copyright © 2013 SciRes. OPEN ACCESS
through the temporalis muscle is within the hairline and
more aesthetic, penetration of the pins through the tem-
poralis muscle is painful and may impede the ability to
chew without discomfort. The bone underlying this area
is also thinner and prone to puncture with repeated pin
loosenin g  .
Initial pin placement requires appropriate torque to
prevent loosening and possible skull penetration. Rizzolo
et al.  compared 102 patients with a pin torque of
either 6 or 8 inch-pounds. Thosepins inserted with 6
inch-lbs torque had fewer complications, including loos-
ening, infection, pin change, or loss of pin. Pande et al.
 reported a case of transient brain injury from pin
penetration into thetemporoparietal region of the brain
. This developed 6 hours after the halo was retight-
ened. The patient demonstrated drowsiness, facial
asymmetry, and a weak left hand grip. There was no in-
fection and the patient recovered. The pin was replaced.
Poor pin site hygiene can also lead toinfection. Water
and mild soap are recommended for cleaning the sites.
Agents including povidone-iodine, hydrogen peroxide,
and chlorhexidine have shown higher infection rates .
Also, excessive cleaning can lead to excess granulation
tissue around the pins and subsequent loosening.
Re-tightening of the pins generally occurs at 24 hours
and again after 1 week. Also routine follow up should be
done at 4 - 6 week inter vals.
Antibiotic therapy has been more successful when
begun prior to actual abscess formation. Once an abscess
develops, surgical evacuation completed with antibiotic
therapy becomes the only available option. Some cases
have presented as orbital pain, aphasia, seizure, lethargy,
disorientation, or psychosis [13,14]. As previously men-
tioned, even if adequately treated, these symptoms can
be associated with serious long term cerebral paren-
chyma damage. These include interference with the nor-
mal propagation of electrical impulses, and the site now
becomes a potential seizure focus [5 ,6].
Patients with halo placement are often in the ICU.
Awareness of potential complications from these devices
must be part of the clinicians’ competence. Those with
halo pins and a clinical picture suggestive of infection
require close and detailed evaluation. Pin site infection
should be promptly treated to prevent pin penetration
into the brain and possible deep cranial infection. Early
recognition may reduce morbidity.
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