[Less invasive calibration of lumbar canal stenosis. Results with a tubular muscle retraction system used in 35 patients].
BACKGROUND
The purpose of this study was to evaluate retrospectively the indications, surgical technique, and postoperative findings in a series of 35 patients presenting lumbar canal stenosis due to osteoarthritic degeneration who underwent surgery using a tubular system for muscle retraction.


METHODS
This retrospective analysis included 35 patients, 28 with lumbar canal stenosis on a single level and seven with stenosis on two levels. On the stress images, 8 of these 35 patients presented stable degenerative spondylolisthesis. The surgical technique consisted in using a tubular system for muscle retraction. This enabled access for magnification and microsurgery of the canal, which was opened via an interlaminal approach. Concentric endocanal treatment was thus achieved without laminectomy. The same surgeon performed these 35 operations. The following variables were noted: patient age, level of canal narrowing, initial symptoms, duration of the operation, postoperative pain, use of analgesics, duration of hospital stay, clinical outcome at one and six months.


RESULTS
The postoperative period (mean postoperative stay 2.5 days) was generally uneventful with little pain (mean VAS 0.8). This can be explained by the absence of invasive dissection. Disinsertion of the paravertebral muscles and use of elevators can induce muscle ischemia. The spine is not destabilized since laminectomy is avoided. The six-month outcome showed relief of the initial symptom for 84% of patients. There were two dural breaches with no clinical impact and one patient required revision surgery because of destabilization of a degenerative spondylolisthesis. One other patient also required revision for complementary laminectomy.


CONCLUSIONS
The short-, mid-, and long-term results of spinal canal recalibration using a less invasive approach to lumbar canal stenosis via a tubular system for muscle retraction has provided encouraging results in terms of symptom relief. The early postoperative period is short and uneventful allowing earlier resumption of daily activities. This technique reduces the cost of hospitalization and drugs and is adapted for geriatric patients. The long-term outcome with this technique should be assessed in terms of spinal stability after recalibration.
Faure
P-A
PA
Service de neurochirurgie, CHU de Limoges, 2, avenue Martin-Luther-King, 87042 Limoges cedex, France. partickalainfaure@yahoo.fr
Caire
F
F
Moreau
J-J
JJ
D000368:Aged; D000369:Aged, 80 and over; D002138:Calibration; D004106:Dilatation / Q000295:instrumentation; D019723:Endoscopes; D004867:Equipment Design; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007902:Length of Stay; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D008297:Male; D008866:Microsurgery / Q000295:instrumentation*; D008875:Middle Aged; D009460:Neurologic Examination; D038361:Neuronavigation / Q000295:instrumentation*; D010147:Pain Measurement; D011183:Postoperative Complications / Q000175:diagnosis; D012189:Retrospective Studies; D013130:Spinal Stenosis / Q000175:diagnosis* / Q000601:surgery*; D013168:Spondylolisthesis / Q000175:diagnosis* / Q000601:surgery*; D013525:Surgical Instruments