Does Minimally Invasive Percutaneous Posterior Instrumentation Reduce Risk of Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery? A Propensity-Matched Cohort Analysis.
BACKGROUND
Proximal junctional kyphosis (PJK) is a known complication after spinal deformity surgery. One potential cause is disruption of posterior muscular tension band during pedicle screw placement.


OBJECTIVE
To investigate the effect of minimally invasive surgery (MIS) on PJK.


METHODS
A multicenter database of patients who underwent deformity surgery was propensity matched for pelvic incidence (PI) to lumbar lordosis (LL) mismatch and change in LL. Radiographic PJK was defined as proximal junctional angle >10°. Sixty-eight patients made up the circumferential MIS (cMIS) group, and 68 were in the hybrid (HYB) surgery group (open screw placement).


RESULTS
Preoperatively, there was no difference in age, body mass index, PI-LL mismatch, or sagittal vertical axis. The mean number of levels treated posteriorly was 4.7 for cMIS and 8.2 for HYB (P < .001). Both had improved LL and PI-LL mismatch postoperatively. Sagittal vertical axis remained physiological for the cMIS and HYB groups. Oswestry Disability Index scores were significantly improved in both groups. Radiographic PJK developed in 31.3% of the cMIS and 52.9% of the HYB group (P = .01). Reoperation for PJK was 4.5% for the cMIS and 10.3% for the HYB group (P = .20). Subgroup analysis for patients undergoing similar levels of posterior instrumentation in the cMIS and HYB groups found a PJK rate of 48.1% and 53.8% (P = .68) and a reoperation rate of 11.1% and 19.2%, respectively (P = .41). Mean follow-up was 32.8 months.


CONCLUSIONS
Overall rates of radiographic PJK and reoperation for PJK were not significantly decreased with MIS pedicle screw placement. However, a larger comparative study is needed to confirm that MIS pedicle screw placement does not affect PJK.
*Department of Neurosurgery and§§Department of Orthopaedic Surgery, University of California, San Francisco, California;‡Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan;§Weill Cornell Brain and Spine Center, New York, New York;¶Department of Neurological Surgery, University of Miami, Miami, Florida;‖San Diego Center for Spinal Disorders, La Jolla, California;#Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York;**Department of Neurosurgery, University of South Florida, Tampa, Florida;‡‡Department of Neurosurgery, University of Pittsburgh, Pittsburgh, Pennsylvania;¶¶Cedars-Sinai Spine Center, Los Angeles, California;‖‖Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois;##Rocky Mountain Scoliosis & Spine, Denver, Colorado;***Department of Neurosurgery, University of Virginia, Charlottesville, Virginia.
Praveen V
PV
Mummaneni
Paul
P
Park
Kai-Ming
KM
Fu
Michael Y
MY
Wang
Stacie
S
Nguyen
Virginie
V
Lafage
Juan S
JS
Uribe
John
J
Ziewacz
Jamie
J
Terran
David O
DO
Okonkwo
Neel
N
Anand
Richard
R
Fessler
Adam S
AS
Kanter
Frank
F
LaMarca
Vedat
V
Deviren
R Shay
RS
Bess
Frank J
FJ
Schwab
Justin S
JS
Smith
Behrooz A
BA
Akbarnia
Gregory M
GM
Mundis
Christopher I
CI
Shaffrey
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008141:Lordosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D057216:Propensity Score; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D012600:Scoliosis / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000601:surgery*; D016896:Treatment Outcome