Minimally Invasive Technique for Decompression of Lumbar Foraminal Stenosis Using a Spinal Microendoscope: Technical Note

Abstract

Background: Lumbar foraminal stenosis is a troublesome disease. Decompression of the whole length of the nerve root from the spinal canal to extraforaminal zone is often a surgical requirement due to the difficulty in identifying the nerve compression site before surgery, making preservation of the posterior elements difficult. The authors report a minimally invasive microendoscopic technique for lumbar foraminal stenosis to decompress the entire length of the nerve root from the spinal canal to the extraforaminal zone while preserving the posterior elements.

Surgical Procedure: A tubular retractor is inserted towards the base of the transverse process of the upper vertebra with the retractor tilted inward at a 45-degree angle or greater. Approximately one-third of the pedicle is resected caudally from the base of the transverse process to the spinal canal. After identification of the nerve root, compression factors around the nerve are excised from the spinal canal to the extraforaminal zone without damaging posterior elements such as the facet joints and pars interarticularis.

Results: We treated 6 patients with lumbar foraminal stenosis using this procedure. There were no complications during the operation, and satisfactory results were obtained in all cases.

Conclusions: This microendoscopic technique proved to be useful for the treatment of lumbar foraminal stenosis.

Key words

lumbar foraminal stenosis - minimally invasive spine surgery - microendoscopic surgery - lumbar spine

References

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Appendix

Japanese Orthopaedic Association score for low back pain

I. subjective symptoms
low back pain	none			3
	occasional mild pain			2
	occasional severe pain			1
	continuous severe pain			0
leg pain	none			3
	occasional slight pain			2
	occasional severe pain			1
	continuous severe pain			0
walking ability	normal			3
	able to walk farther than 500 m although it results in symptoms			2
	unable to walk farther than 500 m			1
	unable to walk farther than 100 m			0
II. objective findings
straight leg raising test	normal			2
	30°–70°			1
	<30°			0
sensory disturbance	none			2
	slight disturbance (not subjective)			1
	marked disturbance			0
motor disturbance	normal			2
	slight weakness (grade 4 of 5 in manual muscle-testing)			1
	marked weakness (grade 3–0 of 5 in manual muscle-testing)			0
III. activity of daily living	very difficult	Difficult	Easy
turn over while lying	0	1	2
standing	0	1	2
washing face	0	1	2
leaning forward	0	1	2
sitting (about 1 h)	0	1	2
lifting or holding heavy objective	0	1	2
walking	0	1	2
IV. bladder function	normal			0
	mild dysuria			−3
	severe dysuria			−6
total				29 points

Correspondence