mild procedure for the treatment of
lumbar spinal stenosis: procedure description & safety
®
author: eric j. grigsby, md
Devices Designed for Safety
background
(mild) is a minimally invasive treatment for
pain relief from symptomatic lumbar spinal
stenosis LSS). LSS is a common problem that
can be caused by many factors including
ligamentum flavum hypertrophy. The mild
technique provides removal of small but
adequate amounts of ligament and lamina,
circumventing the need for aggressive
resection of bone and muscle, and avoiding
surgical implants.
objectives
To describe the mild procedure and to
report on safety of this minimally invasive
interlaminar lumbar decompression
method.
methods
Safety of the mild procedure has been
collected for over 250 mild patients.
All patients were treated with the mild
procedure for symptomatic lumbar spinal
stenosis. mild is performed through a 5.1
mm Portal under fluoroscopic guidance,
using light sedation. mild decompression
can be performed unilaterally or bilaterally,
at single or multiple levels.
4.7M 5.1 mm mild® Portal
mild® Portal Stabilizer
Minimizes Tissue Disruption
Minimizes Medial & Lateral Movement
Top Cutting Surface
Cuts Only at Correct Angle
Spoon‐Bill
Maintains Posterior Safety Approach mild®
Depth Guide
mild® Tissue Sculpter
Ensures Depth of Cutting Device
mild®
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Allows Resection & Retraction of Ligamentous Tissue
Key Procedure Safety Points
Posterior approach
Fluoroscopic imaging
Small mild® Portal access (6 G, 5.1 mm)
Local anesthesia with light sedation
No removal of major spinal support structures
Bilateral one‐level operative time < 1 hour
• Patients > 60 years old
• Symptoms
• Uni‐ or bilateral leg pain
• Occurs with axial loading, especially when walking
• Leg pain, numbness, or weakness • Occurs with walking a predictable distance
• Relieved by bending forward, sitting, raising foot or lying down
• Neurogenic back pain • Diagnosis of LSS—patient history of lumbar neurogenic claudication, confirmed via imaging studies
mild® is a Therapeutic Option‐
& You Know When to Stop
Trajectory Planning
Debulk The Ligamentum Flavum • mild® treats LSS by debulking the ligamentum flavum and portions of the lamina to restore space in the spinal canal. Restore Space
In Spinal Canal
• The restoration of space in the canal can be confirmed during the procedure utilizing the epidurogram. • Changes noted in epidurogram (thicker/straighter)
• Improved/easier contrast flow
• Limited remaining tissue available to be removed
6
Contralateral Oblique View
Needle Placement & Epidurogram conclusion
Conclusions:
The mild procedure is a safe method for
the treatment of LSS. No serious device
or procedure-related adverse events were
reported in over 250 mild patients with
follow-up ranging from acute to one
year. This minimally invasive procedure
allows decompression with minimal
tissue disruption. mild offers an early
LSS treatment option following failed
conservative therapy, but prior to more
invasive surgical treatment.
mild® Typical Clinical Findings
• Radiating to buttocks with ambulation
results
Data were collected and reviewed on
over 250 patients treated with the mild
procedure. To date, there have been no
reports of mild device or procedure-related
serious adverse events (dural tears, nerve
root damage, post-op infection requiring
surgical intervention, hemodynamic
instability, hematomas, blood transfusions
or post-op spinal structural instability).
Posterior Approach & Image Guidance‐
Provide Additional Safety
mild® Tissue Sculpter Use
Needle
• Best imaging view
• Presents the thickest cross‐section of the lamina • Positions the layer of epidural contrast immediately deep to the inner table of the lamina
40‐ 45Angle from AP
Ligamentum Flavum
Safety Comparisons
Discussion & Conclusions
Safety Analysis* mild® Patients Deer/Kapural
Publication on mild® Patients
SPORT **
Number of Patients 263
90
394
Dural Tears
0%
0%
9.2%
Blood Transfusions
0%
0%
14.3%
Overall Adverse Events
Intraoperative
Complications
0%
0%
9.9%
Postoperative Complications
0%
0%
12.3%
*No major intraoperative or postoperative mild Device or procedure‐related adverse events (blood transfusions, dural tears, hematomas, nerve root damage) reported in any studies, publications, or presentations.
** Weinstein, et al, for the SPORT Investigators. Surgical versus Nonsurgical Therapy for LSS. NEJM 2008;358:794‐810.
• mild® is SAFE as demonstrated in > 250 cases
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No dural tears
No blood transfusions
No nerve root damage No hematomas
• mild® safety compares favorably to reports from both open surgery and minimally‐invasive surgery published literature
• mild® offers a safe new therapeutic option, addressing a previous gap in choices available in the LSS treatment algorithm