Computed tomography evaluation of superior-segment facet-joint violation after pedicle instrumentation of the lumbar spine with a midline surgical approach.
METHODS
Retrospective study.


OBJECTIVE
To determine the frequency of pedicle screw violation of superior nonfused facet joints adjacent to the most cephalad pedicle screws after a midline approach for lumbar fusion.


BACKGROUND
Facet-joint violations have been evaluated in patients undergoing lumbar pedicle screw instrumentation and fusion with a Wiltse muscle-splitting approach, but not via the more common midline approach.


METHODS
Between 1995 and 2003, 204 patients underwent this procedure. Computed tomography scans (within 1 year postsurgery) were evaluated independently for superior facet-joint violation. chi tests were used to examine bivariate associations of superior level facet-joint violation, patient age, construct level, diagnosis, and revision status for significance (P < or = 0.05).


RESULTS
Superior-level facet-joint violation occurred in 24% of patients and 15% of screws, twice as often on the left side (P = 0.0396) than on the right, more frequently in single than in multiple-level procedures (P < 0.0001), and most frequently with the most cephalad screws at L5 (48%). We found no significant associations between violation rates and other designated parameters.


CONCLUSIONS
The left side, single-level fusion, and most cephalad pedicle screws at L5 are targets for interventions to reduce pedicle violations in this procedure.
Moshirfar
Ali
A
Department of Orthopaedic Surgery, Johns Hopkins Bayview Medical Center, Baltimore, MD 21224-2780, USA. ehenze1@jhmi.edu
Jenis
Louis G
LG
Spector
Leo R
LR
Burke
Patrick J
PJ
Losina
Elena
E
Katz
Jeffrey N
JN
Rand
Frank F
FF
Tromanhauser
Scott G
SG
Banco
Robert J
RJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws / Q000009:adverse effects*; D005260:Female; D005593:Fracture Fixation, Internal / Q000009:adverse effects; D006801:Humans; D016268:Internal Fixators / Q000009:adverse effects; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D021801:Zygapophyseal Joint / Q000473:pathology / Q000601:surgery*