This study evaluated the effectiveness of a selective nerve root block (SNRB) for a lumbar spinal stenosis (LSS) that indicated surgery.

Twenty-one LSS patients, who were indicated for surgery but could not be operated on due to a high anesthetic risk, were evaluated retrospectively an evaluated on average of 19.5 months (range, 12 to 60 months) following the SNRB from April 1998 to October 2002. There were 9 males and 12 females with a mean age of 66.4 years (range, 59 to 78 years). The medical records and radiologic studies were reviewed, and a telephone interview was carried out where needed. The anesthetic risk was evaluated by the American Society of Anesthesiologists (ASA) physical status classification. The Kirkaldy-Willis criteria (at 9 months after SNRB and last FU) and the recurrence of symptoms (at 2 weeks, 1 month, 3 months, 5 months, 9 months after the SNRB, and the last FU) were analyzed.

Among the 21 patients, 8 patients were in the ASA class 3, 13 in class 4. The major physical conditions that indicated a high anesthetic risk was cardiac problems in 17 patients, renal problems in 2, and endocrine problem in 2. The interval between the onset of symptom and the SNRB ranged from one month to 30 years (average, 41.6 months). All but 3 patients had a recurrence of their symptoms at an average 1.9 months (range, 1 day to 9 months) after the SNRB. According to the Kirkardy-Wills criteria, 9 months after SNRB, the results were good in 1 patient, fair in 2, and poor in 18. At the last follow-up, all but 4 patients did not show a chang in their status according to the Kirkardy-Wills criteria, and 4 patients improved (poor to good in 2, poor to fair in 2) without treatment.

The symptoms of LSS improved for a very short period (average, 1.9 month) by SNRB. These results suggest that SNRB suitable for the LSS patients who require need surgery.