-Original-

Microsurgical Medial Fenestration with an Ultrasonic Bone Curette for Lumbar Foraminal Stenosis

Daijiro Morimoto¹, Toyohiko Isu¹, Kyongsong Kim², Atsushi Sugawara³, Ryoji Matsumoto¹ and Masanori Isobe¹

¹Department of Neurosurgery, Kushiro Rosai Hospital, Hokkaido
²Department of Neurosurgery, Graduate School of Medicine, Nippon Medical School
³Department of Neurosurgery, Iwate Medical School

Background: Misdiagnosis and inadequate treatment of lumbar foraminal stenosis (LFS) are the most common causes of failed back surgery. Although several surgical procedures have been reported, the optimal surgical treatment remains controversial.
Aim: We describe our method of microsurgical medial fenestration using an ultrasonic bone curette (Sonopet, Stryker Corp., Kalamazoo, MI, USA) to treat patients with LFS and report our early results.
Patients and Methods: We followed up 26 patients who had undergone microsurgical medial fenestration at least 1 year earlier. The patients were 15 men and 11 women with a mean age at surgery of 59.5 years; the mean follow-up period was 30.6 months. The affected nerve root was at L4 in 1 patient and at L5 in 25. Evaluation of our clinical results was based on the Japanese Orthopedic Association score.
Results: There were no intraoperative surgery-related complications. After surgery, 1 patient had recurrence of L5 radiculopathy associated with iatrogenic spondylolysis. He was successfully treated with resection of the inferior articular process without fusion surgery; there was loss of disc height without obvious instability at the corresponding level. The Japanese Orthopedic Association scores showed significant improvement at 1 month after surgery and at final follow-up (p<0.001). No patient had spinal instability or malalignment postoperatively.
Conclusions: Microsurgical medial fenestration using Sonopet, a less-invasive surgical technique that does not result in spinal instability or malalignment, yielded excellent clinical outcomes.

J Nippon Med Sch 2012; 79: 327-334

Keywords
lumbar foraminal stenosis, microsurgical medial fenestration, ultrasonic bone curette, minimal invasive surgery, clinical outcome

Correspondence to
Daijiro Morimoto, MD, PhD, Department of Neurosurgery, Kushiro Rosai Hospital, 13-23 Nakazono, Kushiro, Hokkaido 085-8533, Japan
dai_sampo@yahoo.co.jp

Received, December 7, 2011
Accepted, February 10, 2012