Comparison of teriparatide and bisphosphonate treatment to reduce pedicle screw loosening after lumbar spinal fusion surgery in postmenopausal women with osteoporosis from a bone quality perspective.
METHODS
Prospective study.


OBJECTIVE
To examine the efficacy of teriparatide or bisphosphonate treatment to reduce pedicle screw (PS) loosening after instrumented lumbar posterolateral fusion in postmenopausal women with osteoporosis.


BACKGROUND
Failure of fixation caused by loosening of PSs in osteoporosis is a problem in spinal surgery. Oral administration of bisphosphonate or intermittent injection of parathyroid hormone treatment increases bone mass and reduces the risk of osteoporotic vertebral fractures. Although these treatments may be factor in improving bone quality, a clinical study of the efficacy of bisphosphonate or parathyroid hormone for reducing PS loosening that addresses the quality of the bone marrow and pedicle cortex has not yet been reported.


METHODS
Sixty-two women with osteoporosis diagnosed with degenerative spondylolisthesis were divided into 3 groups: a teriparatide group (daily subcutaneous injection of 20 μg of teriparatide, n = 20), a bisphosphonate group (daily oral administration 2.5 mg of risedronate, n = 20), and a control group (without medication for osteoporosis, n = 22). All patients underwent decompression and 1- or 2-level instrumented posterolateral fusion with a local bone graft. Loosening of PSs and surgical outcome were evaluated radiographically, clinically, and by computed tomography 12 months after surgery.


RESULTS
At 12-month follow-up, the incidence of PS loosening was 7% to 13% in the teriparatide group, 13% to 26% in the risedronate group, and 15% to 25% in the control group. The incidence of PS loosening in the teriparatide group was significantly lower than that in the risedronate or the control group (P < 0.05). In contrast, the extent of PS loosening in the risedronate group was not significantly different from that in the control group (P > 0.05).


CONCLUSIONS
Our findings suggest that administration of teriparatide increased the quality of the lumbar spine bone marrow and pedicle cortex.
Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan. sohtori@faculty.chiba-u.jp
Seiji
S
Ohtori
Gen
G
Inoue
Sumihisa
S
Orita
Kazuyo
K
Yamauchi
Yawara
Y
Eguchi
Nobuyasu
N
Ochiai
Shunji
S
Kishida
Kazuki
K
Kuniyoshi
Yasuchika
Y
Aoki
Junichi
J
Nakamura
Tetsuhiro
T
Ishikawa
Masayuki
M
Miyagi
Hiroto
H
Kamoda
Miyako
M
Suzuki
Gou
G
Kubota
Yoshihiro
Y
Sakuma
Yasuhiro
Y
Oikawa
Kazuhide
K
Inage
Takeshi
T
Sainoh
Masashi
M
Takaso
Tomoaki
T
Toyone
Kazuhisa
K
Takahashi
D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000627:therapeutic use; D001863:Bone Screws; D012968:Etidronic Acid / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy*; D058866:Osteoporotic Fractures / Q000517:prevention & control; D011446:Prospective Studies; D000068296:Risedronic Acid; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D019379:Teriparatide / Q000627:therapeutic use*; D016896:Treatment Outcome
D050071:Bone Density Conservation Agents; D019379:Teriparatide; D000068296:Risedronic Acid; D012968:Etidronic Acid