Clinical outcome following DIAM implantation for symptomatic lumbar internal disk disruption: a 3-year retrospective analysis.
OBJECTIVE
Internal disk disruption (IDD), an early event of lumbar disk degeneration, is the most common cause of low back pain. Since increased intradiskal pressure (IDP) is associated with symptoms and progression of disk degeneration, unloading a painful disk with an interspinous process device (IPD) is a rational treatment option. The goal of this study was to evaluate the effectiveness of dynamic stabilization with an IPD in the treatment of symptomatic IDD of the lumbar spine.


METHODS
Patients with symptomatic IDD were treated with implantation of an IPD, the device for intervertebral assisted motion (DIAM). Diagnosis of IDD was based on typical MRI finding of posterior annular high-intensity zone and positive provocative test on discography. IDP was analyzed intraoperatively. Axial back and leg pain was evaluated with visual analog scale, functional status with Oswestry Disability Index, and final clinical outcomes with Odom criteria. Data from 34 patients followed up for at least 3 years were collected.


RESULTS
DIAM implantation significantly reduced IDP (n=11,P<0.0001). All 34 patients reported symptom relief. Thirty-one patients (91%) remained symptom free until the last followups. Three patients (9%) experienced recurrence of pain, of which the causes were unrelated to the IDD or surgery. Disk status at the DIAM-implanted segments remained stable. Segmental flexion/extension mobility was preserved in 27 of 30 patients with preoperative mobility. No proximal or distal adjacent segment degeneration was observed. The final clinical outcomes were excellent/good in 31 and fair/poor in three patients.


CONCLUSIONS
For patients with symptomatic IDD, dynamic stabilization with DIAM provides pain relief and functional improvement. The implantation maintains disk status and prevents progression of disk degeneration, without compromising segmental flexion/extension mobility or causing adjacent segment degeneration.
Department of Neurosurgery, E-Da Hospital.
Kang
K
Lu
Department of Neurosurgery, E-Da Hospital.
Po-Chou
PC
Liliang
Department of Neurosurgery, E-Da Hospital.
Hao-Kuang
HK
Wang
Department of Neurosurgery, E-Da Hospital.
Jui-Sheng
JS
Chen
Department of Neurosurgery, E-Da Hospital.
Te-Yuan
TY
Chen
Department of Family Medicine, E-Da Hospital.
Ruyi
R
Huang
Department of Neurosurgery, E-Da Hospital; Department of Neurosurgery, E-Da Cancer Hospital, College of Medicine, I-Shou University, Kaohsiung, Taiwan.
Han-Jung
HJ
Chen
DIAM; internal disk disruption; interspinous process device; intradiskal pressure; lumbar disk degeneration