Abstract

Minimally invasive modalities have demonstrated efficacy in the treatment of neurogenic claudication. Direct comparisons, however, between complication rates of these newer techniques with open surgical techniques for lumbar decompression are lacking. This single-institution study examined neurogenic claudicants between August 2007 and June 2009. A total of 26 patients received open surgical decompression, and 23 patients microendoscopicdecompression. Baseline demographic characteristics, peri-operative morbidity and mortality, length of hospital stay, and final disposition following hospitalization were recorded. Morbidity was divided into major and minor categories as defined by degree of requisite intervention and adverse impact on hospital stay. Average age, number of surgical levels, and pre-operative American Society of Anesthesiologists Physical Status Index scores were similar in each group (p>0.05). While minimally invasive surgery may be associated with slightly longer operative times, there is decreased blood loss, shorter hospital stays, and likely decreased requirements for ancillary support services upon discharge.

Copyright © 2011 Elsevier Ltd. All rights reserved.

Abstract

BACKGROUND:

Lumbar spinal stenosis and neurogenic claudication functionally impact thousands of patients per year. Those who fail conservative therapies and are not surgical candidates due to co-morbid conditions have few interventional options available. The recently described mild® procedure (Minimally Invasive Lumbar Decompression) is a candidate to fill this void. While 2 studies have reported no major adverse events with this procedure, the typical post-procedure patient course has not been previously described.

OBJECTIVE:

To examine the minor adverse events and periprocedural course associated with mild. Additionally, to evaluate the efficacy of the procedure with regard to pain relief and functional status.

DESIGN:

Retrospective evaluation.

METHODS:

Forty-two consecutive patients meeting magnetic resonance imaging (MRI) criteria for mildunderwent the procedure performed by 2 interventional pain management physicians working at the same center. The pre and post procedure visual analog scale (VAS) as well as markers of global function were recorded. Major and minor adverse events were tracked and patient outcomes reported.

RESULTS:

There were no major adverse events reported. Of the minor adverse events, soreness lasting 3.8 days was most frequently reported. No patients required overnight observation and only 5 required postoperative opioid analgesics. Patients self-reported improvement in function as assessed by ability to stand and ambulate for greater than 15 minutes, whereas prior to the procedure 98% reported significant limitations in these markers of global functioning. Visual analog pain scores were significantly decreased by 40% from baseline. Eighty-six percent of the patients reported that they would recommend the mild procedure to others.

CONCLUSION:

The mild procedure appears to be a safe and likely effective option for treatment of neruogenic claudication in patients who have failed conservative therapy and have ligamentum flavum hypertrophy as the primary distinguishing component of the stenosis.

Abstract

BACKGROUND:

Neurogenic claudication due to lumbar spinal stenosis is a common problem that can be caused by many factors including hypertrophic ligamentum flavum, facet hypertrophy, and disc protrusion. When standard medical therapies such as pain medication, epidural steroid injections, and physical therapy fail, or when the patient is unwilling, unable, or not severe enough to advance to more invasive surgical procedures, both physicians and patients are often left with a treatment dilemma. Patients in this study were treated with mild, an ultra-minimally invasive lumbar decompression procedure using a dorsal approach. The mildprocedure is performed under fluoroscopic imaging to resect bone adjacent to, and achieve partial resection of, the hypertrophic ligamentum flavum with minimal disruption of surrounding muscular and skeletal structure.

OBJECTIVE:

To assess the clinical application and patient safety and functional outcomes of the mildlumbar decompression procedure in the treatment of symptomatic central canal spinal stenosis.

STUDY DESIGN:

Multi-center, non-blinded, prospective clinical study.

SETTING:

Fourteen US spine specialist practices.

METHODS:

Between July 2008 and January 2010, 78 patients were enrolled in the MiDAS I Study and treated with the mild procedure for lumbar decompression. Of these patients, 6-week follow-up was available for 75 patients. OUTCOME ASSESSMENT: Visual Analog Score (VAS), Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), and SF-12v2 Health Survey. Outcomes were assessed at baseline and 6 weeks post-treatment.

RESULTS:

There were no major device or procedure-related complications reported in this patient cohort. At 6 weeks, the MiDAS I Study showed statistically and clinically significant reduction of pain as measured by VAS, ZCQ, and SF-12v2. In addition, improvement in physical function and mobility as measured by ODI, ZCQ, and SF-12v2 was statistically and clinically significant in this study.

LIMITATIONS:

This is a preliminary report encompassing 6-week follow-up. There was no control group.

CONCLUSIONS:

In this 75-patient series, and in keeping with a previously published 90-patient safety cohort, the mild procedure proved to be safe. Further, based on near-term follow-up, the mildprocedure demonstrated efficacy in improving mobility and reducing pain associated withlumbar spinal canal stenosis.

Abstract

BACKGROUND AND OBJECTIVES:

Lumbar canal stenosis is a common source of chronic low back and leg pain. MinimallyInvasive Lumbar Decompression (mild(R)) is a new minimally invasive treatment for pain relief from symptomatic central lumbar canal stenosis. The procedure involves limited percutaneous laminotomy and thinning of the ligamentum flavum in order to increase the critical diameter of the stenosed spinal canal. The objective of this technical report is to evaluate the acute safety of the mild procedure.

METHODS:

Manual and electronic chart survey was conducted by 14 treating physicians located in 9 U.S. states on 90 consecutive patients who underwent the mild procedure. Patients within local geographical practice areas were selected in keeping with product Instructions For Use. Those patients requiring lumbar decompression via tissue resection at the perilaminar space, within the interlaminar space and at the ventral aspect of the lamina were treated. Data collected included any complications and/or adverse events occurring during or immediately following the procedure prior to discharge.

RESULTS:

Of 90 procedures reviewed, there were no major adverse events or complications related to the devices or procedure. No incidents of dural puncture or tear, blood transfusion, nerve injury, epidural bleeding, or hematoma were observed.

LIMITATIONS:

Data were not specifically collected; however, regardless of difficulty, in this series none of the procedures were aborted and none resulted in adverse events. Efficacy parameters were not collected in this safety survey.

CONCLUSIONS:

This review demonstrates the acute safety of the mild procedure with no report of significant or unusual patient complications. To establish complication frequency and longer-term safety profile associated with the treatment, additional studies are currently being conducted. Survey data on file at Vertos Medical, Inc.

Abstract

STUDY DESIGN:

Outcomes of muscle-preserving interlaminar decompression (MILD) for the lumbar spine are reported.

OBJECTIVE:

To verify the clinical findings of lumbar MILD.

SUMMARY OF BACKGROUND DATA:

A preliminary short-term follow-up study of lumbar MILD demonstrated satisfactory neural recovery and reduced invasiveness. METHODS.: The initial 105 consecutive patients withlumbar spinal canal stenosis were included in this study. A total of 210 intervertebral levels were decompressed. There were 48 women and 57 men, and the mean patient age was 68.8 years. The postoperative follow-up period ranged from 8 to 44 months (mean 21.3 months). Eighty-one patients showed cauda equina claudication, and 75 patients complained of radicular pain. Preoperative imaging studies demonstrated that all patients had moderate-to-severe spinal canal stenosis, 75 patients had degenerative spinal canal stenosis, and the remaining 30 had degenerative spondylolisthesis. Pre- and postoperative Japanese Orthopedic Association scores, intraoperative blood loss, surgical complications, and postoperative ambulation were recorded. RESULTS.: One hundred five patients underwent lumbar MILD procedure for 210 interspinous levels, 42 patients for 2 levels, 37 patients for 1 level, 17 for 3 levels, 7 for 4 levels, and 2 for 5 levels. Cerebrospinal fluid leakage due to dural tear occurred in 2 patients. Expansion of the operative field was not necessary to repair the dura mater. The mean operation time was 104.9 minutes per level, and mean intraoperative blood loss was 29.4 g per level. Neurologic improvement was demonstrated in all patients. The mean recovery rate calculated with pre- and postoperative Japanese Orthopedic Association scores was 64.9%. Patients started to stand or walk an average of 2.5 days after surgery. None of the patients presented with wound infection. There was no neurologic complication in this series.

CONCLUSION:

In MILD for the lumbar spine, damage to the posterior stabilizing structures such as the intervertebral facet joints, paravertebral muscles, thoracolumbar fascia, supra- and interspinous ligaments, can be minimized, while preserving the function of the spinous processes as lever arms for lumbar extension.

Abstract

STUDY DESIGN:

Outcomes of muscle-preserving interlaminar decompression (MILD) for the lumbar spine are reported.

OBJECTIVE:

To verify the clinical findings of lumbar MILD.

SUMMARY OF BACKGROUND DATA:

A preliminary short-term follow-up study of lumbar MILD demonstrated satisfactory neural recovery and reduced invasiveness. METHODS.: The initial 105 consecutive patients withlumbar spinal canal stenosis were included in this study. A total of 210 intervertebral levels were decompressed. There were 48 women and 57 men, and the mean patient age was 68.8 years. The postoperative follow-up period ranged from 8 to 44 months (mean 21.3 months). Eighty-one patients showed cauda equina claudication, and 75 patients complained of radicular pain. Preoperative imaging studies demonstrated that all patients had moderate-to-severe spinal canal stenosis, 75 patients had degenerative spinal canal stenosis, and the remaining 30 had degenerative spondylolisthesis. Pre- and postoperative Japanese Orthopedic Association scores, intraoperative blood loss, surgical complications, and postoperative ambulation were recorded. RESULTS.: One hundred five patients underwent lumbar MILD procedure for 210 interspinous levels, 42 patients for 2 levels, 37 patients for 1 level, 17 for 3 levels, 7 for 4 levels, and 2 for 5 levels. Cerebrospinal fluid leakage due to dural tear occurred in 2 patients. Expansion of the operative field was not necessary to repair the dura mater. The mean operation time was 104.9 minutes per level, and mean intraoperative blood loss was 29.4 g per level. Neurologic improvement was demonstrated in all patients. The mean recovery rate calculated with pre- and postoperative Japanese Orthopedic Association scores was 64.9%. Patients started to stand or walk an average of 2.5 days after surgery. None of the patients presented with wound infection. There was no neurologic complication in this series.

CONCLUSION:

In MILD for the lumbar spine, damage to the posterior stabilizing structures such as the intervertebral facet joints, paravertebral muscles, thoracolumbar fascia, supra- and interspinous ligaments, can be minimized, while preserving the function of the spinous processes as lever arms for lumbar extension.

Abstract

STUDY DESIGN:

Outcomes of muscle-preserving interlaminar decompression (MILD) for the lumbar spine are reported.

OBJECTIVE:

To verify the clinical findings of lumbar MILD.

SUMMARY OF BACKGROUND DATA:

A preliminary short-term follow-up study of lumbar MILD demonstrated satisfactory neural recovery and reduced invasiveness. METHODS.: The initial 105 consecutive patients withlumbar spinal canal stenosis were included in this study. A total of 210 intervertebral levels were decompressed. There were 48 women and 57 men, and the mean patient age was 68.8 years. The postoperative follow-up period ranged from 8 to 44 months (mean 21.3 months). Eighty-one patients showed cauda equina claudication, and 75 patients complained of radicular pain. Preoperative imaging studies demonstrated that all patients had moderate-to-severe spinal canal stenosis, 75 patients had degenerative spinal canal stenosis, and the remaining 30 had degenerative spondylolisthesis. Pre- and postoperative Japanese Orthopedic Association scores, intraoperative blood loss, surgical complications, and postoperative ambulation were recorded. RESULTS.: One hundred five patients underwent lumbar MILD procedure for 210 interspinous levels, 42 patients for 2 levels, 37 patients for 1 level, 17 for 3 levels, 7 for 4 levels, and 2 for 5 levels. Cerebrospinal fluid leakage due to dural tear occurred in 2 patients. Expansion of the operative field was not necessary to repair the dura mater. The mean operation time was 104.9 minutes per level, and mean intraoperative blood loss was 29.4 g per level. Neurologic improvement was demonstrated in all patients. The mean recovery rate calculated with pre- and postoperative Japanese Orthopedic Association scores was 64.9%. Patients started to stand or walk an average of 2.5 days after surgery. None of the patients presented with wound infection. There was no neurologic complication in this series.

CONCLUSION:

In MILD for the lumbar spine, damage to the posterior stabilizing structures such as the intervertebral facet joints, paravertebral muscles, thoracolumbar fascia, supra- and interspinous ligaments, can be minimized, while preserving the function of the spinous processes as lever arms for lumbar extension.