Less invasive surgery for treating adult spinal deformities: ceiling effects for deformity correction with 3 different techniques.
OBJECTIVE
Minimally invasive surgery (MIS) options for the treatment of adult spinal deformity (ASD) have advanced significantly over the past decade. However, a wide array of options have been described as being MIS or less invasive. In this study the authors investigated a multiinstitutional cohort of patients with ASD who were treated with less invasive methods to determine the extent of deformity correction achieved.


METHODS
This study was a retrospective review of multicenter prospectively collected data in 85 consecutive patients with ASD undergoing MIS surgery. Inclusion criteria were as follows: age older than 45 years; minimum 20° coronal lumbar Cobb angle; and 1 year of follow-up. Procedures were classified as follows: 1) stand-alone (n = 7); 2) circumferential MIS (n = 43); or 3) hybrid (n = 35).


RESULTS
An average of 4.2 discs (range 3-7) were fused, with a mean follow-up duration of 26.1 months in this study. For the stand-alone group the preoperative Cobb range was 22°-51°, with 57% greater than 30° and 28.6% greater than 50°. The mean Cobb angle improved from 35.7° to 30°. A ceiling effect of 23° for curve correction was observed, regardless of preoperative curve severity. For the circumferential MIS group the preoperative Cobb range was 19°-62°, with 44% greater than 30° and 5% greater than 50°. The mean Cobb angle improved from 32° to 12°. A ceiling effect of 34° for curve correction was observed. For the hybrid group the preoperative Cobb range was 23°-82°, with 74% greater than 30° and 23% greater than 50°. The mean Cobb angle improved from 43° to 15°. A ceiling effect of 55° for curve correction was observed.


CONCLUSIONS
Specific procedures for treating ASD have particular limitations for scoliotic curve correction. Less invasive techniques were associated with a reduced ability to straighten the spine, particularly with advanced curves. These data can guide preoperative technique selection when treating patients with ASD.
University of Miami, Neurosurgery, Miami, Florida.
Michael Y
MY
Wang
Praveen V
PV
Mummaneni
Kai-Ming G
KM
Fu
Neel
N
Anand
David O
DO
Okonkwo
Adam S
AS
Kanter
Frank
F
La Marca
Richard
R
Fessler
Juan
J
Uribe
Christopher I
CI
Shaffrey
Virginie
V
Lafage
Raqeeb M
RM
Haque
Vedat
V
Deviren
Gregory M
GM
Mundis
D000368:Aged; D001863:Bone Screws; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods; D013131:Spine / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome