Keywords
ioCT - spinal - epidural - hematoma - complication
Introduction
Anterior cervical spine operations involve decompression of the spinal canal and cervical
nerve roots by discectomy or corpectomy in combination with fusion via cage or replacement
of a vertebral body. Bailey and Badgley,[1] Smith and Robinson,[2] and Cloward[3] introduced the technique first in the 1950s and the early 1960s.
The reported rates of clinical success in the literature are high[4] and low-complication rates described, such as wound infection (0.4–2%), cerebral
spinal fluid leak (1%), hematoma (1%), hoarseness or dysphagia (9%), nonfusion[5] or accelerated adjacent disc degeneration (2.9%).[6] One of the most serious adverse events associated with cervical spine surgery is
a postoperative spinal epidural hematoma (SEH), compressing the cervical spinal cord.
Although rates of SEH after lumbar spine surgery are reported in 33 to 100%[7]
[8]
[9] on imaging, most of them remain asymptomatic. Reported rates of symptomatic SEH
after anterior decompressive cervical spine surgery vary from 0.1 to 3.2%, slightly
elevated in case of corpectomy compared with multilevel discectomy and fusion.[10]
[11] If this occurs and is not evacuated immediately, persistent neurological deficits
(viz., such as paralysis or even death because of compromised spontaneous breathing)
may occur.
Here, we present a case of SEH after two-level discectomy leading to paralysis within
an hour postoperatively, and the advantage of an intraoperative CT (ioCT) providing
an immediate diagnosis and control of hematoma evacuation.
Case Report
A 69-year-old female patient presented with cervical radiculopathy and myelopathy.
Magnetic resonance imaging (MRI) of the cervical spine revealed a multilevel cervical
spondylotic myelopathy (CSM) at C4/5 and C5/6 ([Fig. 1]). Anterior decompression and fusion (ACDF) of both levels was performed uneventfully.
Fig. 1 (a) Sagittal MRI scan showing cervical myelopathy at level C4/5 and C5/6, (b) axial
slice at level C4/5, and (c) at level C5/6 with concentric constriction of the spinal
canal. MRI, magnetic resonance imaging.
After weaning the patient presented without neurological deficit. Within 45 minutes
after surgery, deterioration with progressive motor deficit to complete tetraplegia
developed in the recovery unit. Because of this dramatic deficit and a rising sensory
deficit level during preparation for reintubation, an emergency MRI scan was dismissed.
A CT scan in the operation theater with the patient already positioned for anterior
cervical surgery was performed instead (11.55 am) in suspicion of a spinal cord compression due to cage dislocation or hematoma. It
revealed a massive ventral hematoma preponderantly behind C3 and C4 with compression
of the spinal cord ([Fig. 2a]).
Fig. 2 (a) CT scan 1 hour after two-level ACDF of a patient developing complete tetraplegia.
A large hematoma ventral to the dural sac can be seen from C2 to C6, (b) ioCT scan
after corpectomy C5 revealing a residual hematoma behind the vertebral body of C2
to C3, (c) second ioCT scan after additional corpectomy of C4, showing minimal residual
hematoma behind C2, and (d) not compressing the spinal cord. ACDF, anterior decompression
and fusion; CT, computed tomographic, ioCT, intraoperative CT.
The wound was rapidly reopened, the plate and both cages removed and hematoma was
sucked through the intervertebral spaces within less than 30 minutes after the initial
scan. Corpectomy of the C5 was performed and a blood clot was removed behind C4 supported
by rinsing via an external ventricular drainage catheter until the hematoma seemed
to be evacuated adequately. Using the ioCT, another scan was performed 58 minutes
after the skin incision and a residual hematoma behind the vertebral body C3 was detected
([Fig. 2b]).
The approach was enlarged by additional corpectomy of C4 to ensure an adequate evacuation
of the hematoma. The second ioCT (104 minutes after the incision) showed only a small
residual hematoma behind C2 without significant compression of the spinal cord and
the dural sac ([Fig. 2c]). Osteosynthesis was achieved using a 35-mm mesh-cage, packed with autograft bone
and a ventral fixation with a 45-mm plate.
After prolonged hemostasis and wound closure, a last control scan was performed, showing
a sufficient ventral decompression and confirmed correct positioning of the bicortical
screws ([Fig. 3]). Before reoperation prophylactic intravenous antibiotic and intravenous corticoid
was administered.
Fig. 3 Postoperative control scan, showing adequate decompression and sufficient anchoring
of the bicortical screws in C6 vertebral body.
After extubation the patient presented with physiological movement of the upper and
lower limbs and spontaneous breathing. Meticulous testing on the first postoperative
day revealed a mild paraparesis (weak 4 out of 5) without a sensory deficit.
Supported by physiotherapeutic and ergotherapeutic treatment, the patient could be
mobilized rapidly and she was able to walk alone for short distances after 2 weeks.
For further rehabilitation, the patient was transferred to a specialized center, where
the neurological deficits further declined. After 1 month of the operation the patient
had recovered completely from her major neurological deficits.
Discussion
ACDF is the primary approach for treating CSM. Common complications such as wound
problems, temporary hoarseness, or mild dysphagia range up to 10%[5] in patients undergoing ACDF. Symptomatic SEH after cervical discectomy are described
with an incidence between 0.1 and 0.2%,[9] whereas asymptomatic SEH seem to happen in 30 up to 100% of patients after lumbar
spine surgery.[7]
[8]
[9] In cervical spine surgery, however, a postoperative SEH becomes symptomatic earlier
due to different relation of the neural tissue to the volume of the spinal canal.
In case of new neurological deficits immediately after cervical spine surgery, three
major differential diagnoses have to be made: either a dislocation of the implant
or a postoperative hematoma can compress the spinal cord, leading to a rising motor
or sensible deterioration. Also, an ischemic damage to the spinal cord has to be concerned
as a potential differential diagnosis.
Hans et al described a second look operation without follow-up imaging in suspicion
of local hematoma after acute deterioration in patients after ACDF.[12] Hematomas, however, can spread to levels above, and below the level actually operated.
In fact, in the presented case we found a hematoma spreading over more than two levels.
An adequate decompression would not be possible by removing the implants alone, but
a corpectomy had to be performed. The fact that acute compression of the spinal cord
by coagulated blood has a poor prognosis, if not removed quickly, affirms the need
of adequate and immediate imaging in the case of these complications.
The acute imaging was performed using an ioCT, which delivered precise information,
especially in the detection of hematomas. Also, an eventual dislocation of the implants
could be excluded quickly. Even if MRI is the most effective diagnostic tool for detecting
postoperative SEH or confirmation of an ischemic damage, it is time-consuming, it
can be challenging from a logistical point of view, and it is not always available
immediately ([Fig. 4], online-only). After the sudden progressive neurological deterioration, an ischemic
process was considered in the differential diagnosis, but in order to not lose time,
the CT was performed as first-line imaging in our operating room. If there would not
have been an hemorrhagic explanation for the presented deterioration, the loss of
time would have amounted to only 10 minutes and an immediate MRI could have been performed
for further evaluation thereafter.
Fig. 4 Flowchart comparing the two possible scenarios if a neurological deterioration develops
in the recovery unit. Immediate return to the operating room and rapid imaging using
the CT provides sufficient information in case of hematoma or cage dislocation. If
the CT gives no explanation for the neurological deficits, an MRI is required additionally,
delayed not more than 10 minutes. CT, computed tomography; MRI, magnetic resonance
imaging.
Visualization of the processes dorsal to the cervical vertebrae is difficult in a
regular ACDF approach because it provides only a narrow space to explore the spinal
canal. Even if the approach is amplified in our case with a corpectomy of C5, it can
be difficult to assess the situation at levels superior or inferior to the bony decompression.
Even if a sufficient decompression of the SEH seems to be accomplished, an adequate
intraoperative imaging modality can reassure the success of the operation. Due to
these considerations, several intraoperative imaging tools have been introduced in
neurosurgery, each with its advantages and limitations. Intraoperative MRI suites
surely provide the best visualization of the spinal cord structures, but it resembles
a quite expensive and time-consuming modality.[13] Furthermore, the method has its limitations after ACDF—procedures because of artifacts
of implanted cages, especially in operations with additional anterior plating. Also,
intraoperative ultrasound is deviously limited in visualizing structures dorsal the
vertebral bodies; it may provide information about the spinal cord after amplified
ventral exposure via corpectomy, but especially in degenerative spinal cord compression
with ossified posterior longitudinal ligament, it has limited utility due to artifacts
from residual ossification and limitation by the bony exposure.[14] The value of intraoperative three-dimensional fluoroscopy has instead proven to
give adequate information of (bony) decompression in ACDF—procedures[15] and is widely used. In comparison to ioCT, however, its image quality is inferior
and could miss a hematoma.
The ioCT is widely used in spinal surgery, mostly in fusion-procedures for navigated
placement of pedicle screws, as described in numerous studies. But it also provides
the possibility of immediate confirmation of adequate decompression in handling SEH
after decompressive cervical procedures. To our knowledge, at this time there are
no similar reports in literature about the advantage of ioCT in complication management
after cervical spine surgery.
In the presented case, not only the diagnosis of SEH but also repeated CT during decompression
had dramatic clinical relevance. It led to an additional corpectomy one level above
(see [Fig. 2]), although the senior neurosurgeon (C.T.) had judged the space-occupying hematoma
to be removed. Adequate treatment of a severe complication could be achieved only
by intraoperative imaging in this patient. It must be assumed that stopping surgery
after one-level corpectomy would have necessitated a second revision surgery.
Conclusion
Symptomatic SEH can be readily detected on the operating table, prompting immediate
revision surgery in case of a new postoperative neurological deficit. Without this
imaging modality, a time delay can be associated with a high risk of persistent deficits.
What is more, ioCT allows intraoperative assessment of the adequacy of hematoma removal
and decompression. This avoids further neurological damage and repeated revision surgery
in case of hematoma spread along the spinal cord.
