الفهرس 
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Abstract
Pedicle screw insertion is typically used for degenerative, neoplastic,
infectious, and deformative pathologies associated with axial instability. The
most common technique for the placement of pedicle screws remains the
conventional use of dorsal anatomic landmarks with or without fluoroscopic
assistance. Pedicle screws proper placement is important not only for the
prevention of neurological injury but also for the maintenance of long-term
spinal stability. This study aimed to determine the incidence of screw
misplacement and complications in a group of 32 patients who underwent
lumbosacral transpedicular screw fixation performed using the conventional
open fluoroscopic guided technique.
This was a prospective evaluation study. Subjects were chosen from 2
hospitals: (1) Menofia University Hospital, Egypt and (2) Al-Helal hospital
in Cairo, Egypt. Our study concentrated on degenerative indications
(Herniated intervertebral disc: 14 cases; and spondylolisthesis: 18 cases).
Instrumentation using transpedicular screw fixation was performed between
L3 to S1. The mean age of the patients was 51.8[ranging from 31 to 70
years]. with 13 men and 19 women.
Evaluation of screw placement was performed according to the criteria
initially described by Gertzbein and Robbins modified to include assessment
in the coronal and sagittal reformatted images. Patients who did not have a
postoperative CT scan were excluded from the study. A total of 162 pedicle
screws were evaluated. All patients were followed clinically and
radiologically for at least 6 months after the procedure. After discharge from hospital, clinical and radiological assessment was done at one, three and six months. A correlation between clinical symptoms and radiological violation
was reported.
In this study, 26.5% of screws breached the pedicle wall. However, the
majority (74.4 %, 32/43) of breaches were graded B (<2 mm). None of the
patients with screws presenting this grade of violation developed symptoms
related to the positioning of the screws, therefore in this study, the overall
“clinically acceptable” accuracy rate (<2 mm) was 93.2%. However, these
breaches are representative of the real world and may have clinical
consequences and therefore were included in the final analysis.
In the current study, the neurological injury, defined as the presence of new
postoperative radicular pain and/or sensorimotor weakness, 1.2% (2/162) of
the screws perforated the pedicle by 4 mm or more. Radicular pain without
sensory or motor deficits occurred only in one patient. In 1 patient (3.1% of
all patients), a 51-year-old female with spondylolisthesis at L4-L5, there was
a 5mm medial breach of the right L5 pedicle. This was associated with a
transient right side L5 transient sensory radiculopathy that resolved
spontaneously at the follow-up evaluation. None of the patients with pedicle
violations of >4 mm had postoperative neurologic symptoms and showed no
radiographic signs of instability. No patient developed adjacent segmental
instability after surgery. No assembly disengagement or broken screws were
noted in any patient during follow-up. The number of clinical symptoms
related to screw misplacement in our study appears well within the
previously reported incidence. Nevertheless, no early revision was
performed for screw misplacement.