Change in Modic type 1 and 2 signals after posterolateral fusion surgery.
METHODS
Prospective cohort study.


OBJECTIVE
To examine the change of Modic Type 1 to Type 2 after posterolateral fusion surgery.


BACKGROUND
Lumbar vertebral bone marrow change is divided into Modic types. Magnetic resonance imaging reveals Modic Type 1 and 2 signals. Some reports indicate that with time, Type 1 signals (intervertebral instability) change to Type 2 (restabilization), but the reliability of this assertion is unclear. The current study examines the change of Modic Type 1 signals to Type 2 after posterolateral fusion surgery.


METHODS
Patients with Modic Type 1 and 2 signals were selected (mean age, 65 years). All patients suffered low back pain and leg pain due to lumbar spinal canal stenosis, and underwent decompression and posterolateral fusion surgery. We evaluated change in Modic signal and severity of low back pain (Visual analogue scale score, Japanese Orthopedic Association score, and Oswestry Disability Index before and 24 months after surgery.


RESULTS
Of 21 patients with Modic Type 1 signals before surgery, 2 cases changed to normal bone marrow, 9 to Type 2, and 12 remained Type 1. Of 12 patients with Type 2 signals, none changed to Type 1, 2 changed to normal bone marrow, and 10 remained Type 2. Visual analogue scale score, Japanese Orthopedic Association score, and Oswestry Disability Index improved after surgery; however, low back pain was not significantly associated with signal change after surgery (P > 0.05).


CONCLUSIONS
In the current study, Modic Type 1 signals changed to Type 2; however, Type 2 did not change to Type 1, suggesting that Type 2 signals indicate a stabilized stage. For Modic Type 1 and 2 signals, there were changes to normal bone marrow signals in 4 cases. Therefore, degenerated bone marrow may be able to regenerate after surgical stabilization. We did not show a significant difference between low back pain and signal type.
Ohtori
Seiji
S
Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan. sohtori@faculty.chiba-u.jp
Yamashita
Masaomi
M
Yamauchi
Kazuyo
K
Inoue
Gen
G
Koshi
Takana
T
Suzuki
Munetaka
M
Orita
Sumihisa
S
Eguchi
Yawara
Y
Ochiai
Nobuyasu
N
Kishida
Shunji
S
Takaso
Masashi
M
Kuniyoshi
Kazuki
K
Ishikawa
Tetsuhiro
T
Arai
Gen
G
Miyagi
Masayuki
M
Kamoda
Hiroto
H
Nakamura
Junichi
J
Aoki
Yasuchika
Y
Takahashi
Kazuhisa
K
D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D017352:Echo-Planar Imaging / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D013123:Spinal Fusion / Q000639:trends*; D013130:Spinal Stenosis / Q000503:physiopathology* / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome