The correction of severe deformity often needs osteotomy to improve
the correction in the frontal plane and even moreso in the sagittal
plane. Pedicle subtraction osteotomy (PSO) allows correction in the
sagittal plane of about of 30 at the level of a single vertebra and
restores the sagittal balance in severe deformity.
Materials and methods: We retrospectively studied 15 cases of
pedicle subtraction ostetomy operated between November 2006 and
November 2008. Ten were female and 5 male; the ages were
between 37 and 74 years (mean 59). The diagnosis was: 6 kyphotic
scoliosis, 3 lumbar kyphosis, 2 Scheuermann disease, 2 ankylosing
spondylitis, 2 post-traumatic kyphosis. The levels of osteotomy
were: 1 in T3, 1 in T7, 3 in T12, 1 in L1, 4 in L2, 4 in L3, 1 in L5.
The surgical technique was the same independently of the level. The
arc of the vertebra and the 2 pedicles were removed, and after the
two corresponding nerve roots had been isolated we proceeded to
enlarge the vertebral canal with partial bilateral laminotomy cephalically
and caudally; the two cranial nerve roots were also isolated.
Careful haemostasis is necessary to reduce bleeding which can
sometimes be relevant. The spongy vertebral body is resected
through the enlarged pedicular holes. The posterior wall is removed
thus isolating the posterior longitudinal ligament after careful haemostasis
of the venous plexus. We completed the osteotomy of the
vertebral body with bilateral wedge resection of the lateral part. The
possible correction is obtained with the visual control and somatosensory
and motor –evoked potential monitoring. After the
correction of the sagittal plane has been evalued the internal fixation
with pedicular screws includes at least 2 vertebrae cephalically and
2 vertebrae caudally.
Result: The mean correction was 31 and corrected the sagittal
deformity with good restoration of sagittal balance. In the revision
surgery the anterior flexion of the body has also been corrected.
Complications were minor and without consequences (2 duralesions
repaired with suture, no neurological complication).

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