5. DISCUSSION
The principle of surgical treatment for pyogenic spondylitis is
curettage of the infected lesions with spinal fusion.5Anterior curettage and bone grafting combined with posterior
instrumented fixation have demonstrated good results in maintaining
local spinal alignment.6 However, a combined anterior
and posterior approach is highly invasive. Thoracotomy has been reported
to be strongly associated with respiratory
complications,7 particularly in older patients.
Because the patient in the present case was elderly and had a long
history of pyothorax, the patient’s pleura and vessels were expected to
be severely adhered to the vertebrae using the transthoracic approach,
thereby increasing the difficulty and risk of surgery. Therefore,
single-stage posterior fixation with PPS in combination with curettage
of the vertebral bodies using the separated posterolateral approach was
selected for treatment.
We previously reported a lateral rhachotomy and posterior spinal fusion
with compression hooks for thoracic tuberculous
spondylitis.3 The drawbacks of this method were
relatively weak fixation compared to pedicle screw
systems.8 PPS fixation is more rigid than the hook
system. In addition, PPS is assumed to reduce the risk of instrument
contamination compared to the hook system, which requires conventional
spinal exposure. In an analysis of 10 reports of pyogenic spondylitis
treated with single-stage debridement and spinal instrumentation using
an open, identical approach, Przybylski et al.9reported that 7 out of 106 cases demonstrated recurrent infection. In
the present case, spinal fixation with PPS and curettage were
independent approaches. The PPS was placed closer than usual to the
midline so that screw heads and rods were isolated from the infected
lesion. A thick muscular septum between the posterior instruments and
infected vertebral lesion is expected to prevent the instruments from
bacterial contamination.