J Korean Soc Spine Surg.  2007 Jun;14(2):79-86. 10.4184/jkss.2007.14.2.79.

Minimally Invasive Microscopic Decompression with Tubular Retractor System in Lumbar Spinal Stenosis: Results Comparing with Open Microscopic Decompression

• Jang JH
• Kim JD
• Cha SW

• KMID: 1941659
• DOI: http://doi.org/10.4184/jkss.2007.14.2.79

Abstract

PURPOSE: To compare the two methods of decompression using a microscope with a tubular retractor system and open microscopic decompression in lumbar spinal stenosis.
MATERIALS AND METHODS
The records of patients that had undergone decompression from May 2000 to April 2005 were reviewed. The average follow-up period was 29 months (4~60 months). The duration of hospital stay, estimated blood loss, relief of pain, and operating time were reviewed retrospectively. Analysis was conducted by telephone interview and chart review (McNab's criteria). Pre- and post-operative Visual Analogue Scale (VAS) scores and JOA scores were also evaluated.
RESULTS
Of the total 53 patients, open microscopic decompression was performed on 27 patients, and 26 patients received surgery using microscopic decompression with tubular retractors. There were no patients who had serious complications such as infection or nerve root injury in either of the groups. The average estimated blood loss was 205 cc for the open microscopic decompression group versus 120 cc in the minimally invasive microscopic decompression (MIMD) group (p=0.019). The mean operating time was 2.5 hours in the open microscopic decompression group and 2.2 hours in the MIMD group (p=0.048). As shown by the clinical results, good or excellent results were shown by the McNab's criteria after operation, 85.1% for the open microscopic decompression group and 94.7% for the MIMD group, respectively. The JOA score improved after surgery, with average scores of 14.5 to 24.5 in the open microscopic decompression group, and 15.9 to 25.6 in the MIMD group. The VAS score was reduced after surgery, with an average score of 8.0 to 3.7 in the open microscopic decompression group, and 8.3 to 2.6 in the MIMD group.
CONCLUSION
In terms of blood loss, the MIMD group showed significantly better results than the open microscopic decompression group. The clinical results showed no statistically significant difference between the two groups.

Keyword

Lumbar spinal stenosis; Minimally invasive microscopic decompression; Open microscopic decompression

MeSH Terms

Decompression*
Follow-Up Studies
Humans
Interviews as Topic
Length of Stay
Retrospective Studies
Spinal Stenosis*

Figure

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  Fig. 1. METRx systems (Medtronic-Sofamor Danek, Memphis, TN), (A) METRx system: guide wire, Soft tissue dilator (5.3 mm,9.4 mm, 12.8 mm, 14.8 mm, 16.8 mm, 18.8 mm, 20.8 mm, 22.8 mm), qudrant split blade system (24 mm), (B) flexible arm assembly, (C, D) Kerrison rongeur, curette, probe, dissector, burr.

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  Fig. 2. Sequential dilation and tubular retractor insertion. The tubular retractor is placed over sequential dilators.

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  Fig. 3. Final qudrant split blade system is placed. The flexible arm is secured and sequential dilators are removed.

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  Fig. 4. (A) Ipsilateral laminectomy is performed by burring through the lamina to thickened ligamentum flavum. (B) The retractor is angled toward the midline. The lamina beneath the spinous process is removed. The angling of the tubular retractor allows contralateral decompression.

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