Background: Lumbar spinal stenosis (LSS)
occurs with increasing prevalence in the elderly
population. The American Academy of Orthopedic
Surgeons has estimated that by 2021,
2.4 million adults in the United States (8-11% of
the population) will be affected by this condition.
Surgical options for LSS are being performed
with increased frequency, high cost, and substantial
risk of life-threatening complications.
While nonsurgical treatment options for LSS are
available, they are limited by patient selection
(ligamentum flavum hypertrophy) or high rates
of reoperation (Interspinous process spacer
devices).
This study is the first to suggest a minimally
invasive treatment option for disc-predominate
lumbar central canal stenosis.
Objectives: To evaluate the clinical efficacy of
radiofrequency facilitated manual semi-endoscopic
discectomy utilizing the Disc FX® system
in the treatment of disc-predominate lumbar
spinal stenosis.
Study Design: Single center, prospective, observational
study.
Setting: Multi-specialty private practice clinic.
The Medical Group of South Florida, Jupiter, FL.
Methods: This study involved 6 patients with
disc-predominant lumbar central spinal stenosis.
All patients were treated with the Disc FX®
system. Radiographic evidence of central lumbar
stenosis was confirmed by measurement of minimum
AP canal diameter (mm) performed by 1
board-certified neuroradiologist. Inclusion criteria
included absence of lumbar surgery, physical
therapy within the previous 6 months, failure of
epidural steroid injections (3) within the previous
8 months, spondylolisthesis limited to Grade I,
disc height > 50%, presence of low back axial
pain + leg pain exacerbated by walking, and
relieved with sitting or forward flexion, absence
of dermatomal radicular leg pain, radiographic
evidence of disc displacement > 4 mm from disc
endplate. Zurich claudication (symptom severity
and physical function scale was administered 1
week preoperatively, and again 6 months postoperatively.
There were no patients lost to follow up.
Results: All patients in the study demonstrated
moderate-severe or severe central canal stenosis,
with an average AP canal diameter of 6.63
mm for all treated disc levels and 5.5 mm for the
most severe levels. There was a mean improvement
of 57% in a symptom severity scale and
56% in the physical function scale at 6 months.
This exceeds the improvement reported with
interspinous spacer devices.
Limitations: Limitations include very small
sample size, observational design, non-randomization,
absence of share controls, short
follow-up period.
Conclusion: For patients suffering from discpredominant
lumbar spinal stenosis, The Disc
FX® System provides an effective, low-cost
alternative to surgical intervention.
Key words: Spinal, stenosis, claudication, disc,
Disc FX®, operative, minimally invasive, Zürich
claudication score