|
PROSPECTIVE RADIOGRAPHIC
AND CLINICAL OUTCOMES AND COMPLICATIONS OF SINGLE SOLID ROD INSTRUMENTED
ANTERIOR SPINAL FUSION IN ADOLESCENT IDIOPATHIC SCOLIOSIS.
FA Sweet,
LG Lenke,
K Blanke,
J Whorton,
KH Bridwell
St. Louis, MO, USA
PURPOSE:
To prospectively evaluate outcomes and critically review radiographic
results and complications associated with single solid rod anterior spinal
fusions in adolescent idiopathic scoliosis (AIS) with 2 year minimum follow–up
(range 2 to 4 years).
METHODS:
89 consecutive patients at a single institution with thoracic (n=45) or
lumbar (n=44) AIS were treated by one of two surgeons with a similar anterior
surgical technique using intradiscal structural (Harms) cages placed below
T12, rib autograft, and anterior single solid rod convex compressive instrumentation.
86 patients (95%) were evaluated prospectively with the SRS outcome instrument
and upright radiographs.
RESULTS
(Radiographic):
|
|
Coronal
|
Sagittal (degrees)
|
|
|
Cobb
Degrees
|
Plumb
cm
|
*LIV trans
mm
|
+LIV
tilt
degrees
|
T5
–T12
|
T12
–L2
|
T12
–LIV
|
T12
–Sacrum
|
Instrument
levels
|
|
Thoracic Fusions
(n=43)
|
|
|
Pre
|
55
|
1.6
|
24
|
27
|
24
|
–8
|
–––
|
–65
|
24
|
|
1wk
|
26
|
1.4
|
10
|
12
|
27
|
–6
|
–––
|
–55
|
26
|
|
2yrs
|
29
|
1.0
|
12
|
11
|
30
|
–7
|
–––
|
–63
|
30
|
|
Lumbar Fusions (n=43)
|
|
|
Pre
|
50
|
3.6
|
33
|
29
|
–––
|
0
|
–6
|
–60
|
–6
|
|
1wk
|
13
|
2.2
|
10
|
7
|
–––
|
–7
|
–13
|
–57
|
–12
|
|
2yrs
|
15
|
1.4
|
14
|
6
|
–––
|
–6
|
–10
|
–59
|
–9
|
|
*LIV–trans=LIV translation
from Midline:
+LIV–tilt=LIV angle to the horizontal
|
Coronal correction was 47% in the thoracic
spine and 70% in the lumbar spine. Kyphosis was improved in thoracic fusions
(+6°) and lordosis maintained in lumbar fusions. 5% (n=4) of patients
developed a pseudarthrosis, three with implant failure. Two required a
posterior fusion. A third is considering re–fusion for a re–operation
rate of 2.3% (n=2). The fourth patient was asymptomatic and appeared fused
at two–year follow–up. Two were smokers. Two patients with thoracic pseudarthrosis
had hyper–kyphosis (>40° T5–T12) and weighed more than 70 kg.
RESULTS:
(Clinical outcome): SRS domain average raw scores were mildly improved
for function pre to post op (20.6 to 22.7), worse for pain (19.7 to 16.9)
and unchanged for self–image (10.8 to 10.8). With the SRS satisfaction
domain 87% responded they were satisfied with their results and 88% would
undergo the same treatment again. Patients with pseudarthrosis did not
have significantly lower final SRS scores (93 avg for 3 patients, the
fourth patient scored 77) than those with solid fusions (97 avg, n=82).
CONCLUSION:
Anterior instrumented fusions for AIS using a single solid rod had good
radiographic and clinical outcomes. Consideration should be given to alternate
techniques in larger adolescents (>70kg) with thoracic hyper–kyphosis
(>40°). Poor radiographic outcomes did not correlate with final SRS scores.
|
|