Patients with proximal junctional kyphosis requiring revision surgery have higher postoperative lumbar lordosis and larger sagittal balance corrections.
METHODS
Case control study.


OBJECTIVE
To evaluate risk factors in patients in 3 groups: those without proximal junctional kyphosis (PJK) (N), with PJK but not requiring revision (P), and then those with PJK requiring revision surgery (S).


BACKGROUND
It is becoming clear that some patients maintain stable PJK angles, whereas others progress and develop severe PJK necessitating revision surgery.


METHODS
A total of 206 patients at a single institution from 2002 to 2007 with adult scoliosis with 2-year minimum follow-up (average 3.5 yr) were analyzed. Inclusion criteria were age more than 18 years and primary fusions greater than 5 levels from any thoracic upper instrumented vertebra to any lower instrumented vertebrae. Revisions were excluded. Radiographical assessment included Cobb measurements in the coronal/sagittal plane and measurements of the PJK angle at postoperative time points: 1 to 2 months, 2 years, and final follow-up. PJK was defined as an angle greater than 10°.


RESULTS
The prevalence of PJK was 34%. The average age in N was 49.9 vs. 51.3 years in P and 60.1 years in S. Sex, body mass index, and smoking status were not significantly different between groups. Fusions extending to the pelvis were 74%, 85%, and 91% of the cases in groups N, P, and S. Instrumentation type was significantly different between groups N and S, with a higher number of upper instrumented vertebra hooks in group N. Radiographical parameters demonstrated a higher postoperative lumbar lordosis and a larger sagittal balance change, with surgery in those with PJK requiring revision surgery. Scoliosis Research Society postoperative pain scores were inferior in group N vs. P and S, and Oswestry Disability Index scores were similar between all groups.


CONCLUSIONS
Patients with PJK requiring revision were older, had higher postoperative lumbar lordosis, and larger sagittal balance corrections than patients without PJK. Based on these data, it seems as though older patients with large corrections in their lumbar lordosis and sagittal balance were at risk for developing PJK, requiring revision surgery.


METHODS
3.
*Spine and Scoliosis Service, Hospital for Special Surgery, New York, NY †Pediatric/Adult Spinal Deformity Service, Barnes-Jewish Hospital, St. Louis, MO ‡Adult and Pediatric Spinal Deformity Service, Barnes-Jewish Hospital, St. Louis, MO §Department of Orthopaedic Surgery, Hallym University Sacred Heart Hospital, Medical College of Hallym University, Chuncheon, Gangwon-do, Korea ¶Department of Orthopaedic Surgery, College of Medicine, Chung-Ang University, Seoul, Korea; and ‖Department of Orthopaedic Surgery-Spine Division, Washington University in St. Louis, St. Louis, MO.
Han Jo
HJ
Kim
Keith H
KH
Bridwell
Lawrence G
LG
Lenke
Moon Soo
MS
Park
Kwang Sup
KS
Song
Chaiwat
C
Piyaskulkaew
Tapanut
T
Chuntarapas
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000601:surgery*; D008141:Lordosis / Q000000981:diagnostic imaging / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation; D016896:Treatment Outcome