Postlaminectomy adhesion of the cauda equina. Inhibitory effects of anti-inflammatory drugs on cauda equina adhesion in rats.

STUDY DESIGN: Effects of the systemic administration of anti-inflammatory drugs on cauda equina adhesion after lumbar laminectomy were evaluated in rats. OBJECTIVES: To obtain basic data on preventive measures for lumbar adhesive arachnoiditis. SUMMARY OF BACKGROUND DATA: Laminectomy-induced cauda equina adhesion has been proved by rat experiments and postoperative serial magnetic resonance imaging tests in humans. In rats, laminectomy induces an increase in vascular permeability, resulting in cauda equina adhesion. METHODS: Wistar rats laminectomized from L5 to L6 were divided into three groups: the control group received only vehicle solutions, the indomethacin group received oral indomethacin for 7 days, and the steroid group was administered intraperitoneal methylprednisolone for 3 days. At 24 hours and 3 weeks and 6 weeks after laminectomy, cauda equina adhesion and leakage of a protein tracer from the nutrient vessels were histologically compared in the three groups. RESULTS: Both indomethacin and methylprednisolone significantly suppressed cauda equina adhesion and protein leakage from the nutrient vessels at 24 hours after laminectomy. Rats treated with the anti-inflammatory drugs showed diminution of cauda equina adhesion and the neural degeneration at 3 weeks and 6 weeks after laminectomy. CONCLUSIONS: Anti-inflammatory drug administration before and after laminectomy suppressed cauda equina adhesion as well as facilitating recovery from cauda equina adhesion.

Postlaminectomy adhesion of the cauda equina. Changes of postoperative vascular permeability of the equina in rats.

STUDY DESIGN: The authors evaluated the vascular permeability changes of the cauda equina after lumbar laminectomy in rats. OBJECTIVES: To clarify the early vascular responses in postlaminectomy adhesive arachnoiditis. SUMMARY OF BACKGROUND DATA: Laminectomy-induced cauda equina adhesion has been visualized by postoperative serial magnetic resonance imaging in humans. In laminectomized rats, fibrinous exudation was apparent among the adhered cauda equina. To date, there has been no report of substantial changes in vascular permeability in the cauda equina after lumbar laminectomy. METHODS: Wistar rats laminectomized from L5-L6 were used for four studies; 1) Evans blue albumin tracer study; 2) horseradish peroxidase tracer study; 3) lanthanum tracer study; and 4) fluoroscein isothiocyanate-dextran (molecular weights: 20K, 70K, and 150K) tracer study. Untreated rats were used as controls. RESULTS: 1) In the laminectomized (L5-L6) area, the cauda equina tended to conglomerate from 3 hours after surgery; this was relatively resolved by 6 weeks. Extravascular leakage of Evans blue albumin in the cauda equina appeared at 3 hours after surgery and reached a plateau at 24 hours; it mostly disappeared by 6 weeks. At 24 hours after surgery, the extent of Evans blue albumin extravasation was seen in one or more levels adjacent to the laminectomized area. Evans blue albumin leakage and cauda equina adhesion started to appear in nearly a same phase after laminectomy, followed by a plateau of vascular permeability facilitating complete cauda equina adhesion by 24 hours after surgery. The restoration of Evans blue albumin leakage was noted 1 week after surgery, and tended to precede recovery of the cauda equina adhesion; 2) in the laminectomy group, Horseradish peroxidase penetrated from the lumen to the extracellular space beyond the basal laminae of the endothelial cells. Numerous horseradish peroxidase-labeled vesicles in the endothelial cells were found; 3) There was a significant increase in lanthanum distribution in the endothelial cytoplasm at the laminectomized levels. Lanthanum filled the interendothelial clefts beyond the tight junction, but did not penetrate through the perivascular basal laminae; 4) Fluoroscein isothiocyanate-dextran (20K, 70K, 150K) permeability increased in the laminectomy group, but there was no difference in extravasation of fluoroscein isothiocyanate-dextran, irrespective of the molecular weight. CONCLUSION: Laminectomy consistently induced an increase in vascular permeability in the cauda equina, an increase of vesicular transport in the endothelial cell, and opening of the tight junction early after laminectomy, suggesting breakdown of the blood nerve barrier in the cauda equina. The accelerated permeability may enhance cauda equina adhesion.

Expansive laminoplasty for lumbar intradural lipoma.

We evaluated the pre- and postoperative neurological state of 3 patients with lumbar intradural lipoma. Total resection of the lipoma in the cauda equina was impossible, and partial resection and expansive laminoplasty was carried out. Subsequent neural involvement may depend on the duration of symptoms rather than the extent of resection. Expansive laminoplasty is appropriate in these circumstances since decompression is combined with spinal stabilization.

Nutritional supply to the cauda equina in lumbar adhesive arachnoiditis in rats.

Laminectomy-induced cauda equina adhesion has been proved by rat experiments and postoperative serial MRI in humans. A degenerative change of the cauda equina has been proved when cauda equina adhesion has been prolonged. Since it has not been reported how the nutritional supply is changed in such a condition, we evaluated the glucose supply to the adhered cauda equina in rats. Wistar rats were divided into the following three groups: the control group which received no operation, the laminectomy group which underwent L5-L6 laminectomy only, and the koalin group which received 5 mg of kaolin on the dorsal extradural space following L5-L6 laminectomy. Based on 3H-methyl-glucose uptake study, we analyzed (1) glucose transport from the intraneural vessels to the nerve tissue, and (2) glucose transport from the cerebrospinal fluid to the nerve tissue. We evaluated the relation between the severity of cauda equina adhesion and 3H uptake into the cauda equina. Cauda equina adhesion was observed in 2 of 12 rats in the control group, in 3 of 12 rats in the laminectomy group, and in 18 of 20 rats in the kaolin group. In the 3H-methyl-glucose uptake study, at 12 weeks the glucose transport to the cauda equina from the vessels increased by 44%, and that from the cerebrospinal fluid decreased by 64% in the kaolin group compared with the control group. In the condition of complete cauda equina adhesion, the glucose transport to the cauda equina from the vessels increased by 53% and that from the cerebrospinal fluid remarkably decreased by 72% compared with the normal cauda equina. Considering the greater nutritional importance of the cerebrospinal fluid in the cauda equina, it is most likely that the impairment of nutritional supply to adhered cauda equina may lead to eventual neural degeneration.

Postoperative enteroparesis by patient-controlled analgesia combined with continuous epidural block for patients after posterior lumbar surgery.

This study evaluated postoperative enteroparesis influenced by patient-controlled analgesia combined with continuous epidural block in patients who underwent posterior lumbar surgery. One hundred nine patients were divided into three groups at random (group 1, controls (18 patients); group 2, postoperative patient-controlled analgesia and continuous epidural block (45 patients); group 3, one-shot epidural analgesia, postoperative patient-controlled analgesia, and continuous epidural block (46 patients). The patients in groups 2 and 3 had more satisfactory pain relief and needed analgesics less frequently. However, their clinical abdominal findings the morning after surgery were worse than those in control patients. The times when patients could take any nourishment and eat solid food (rice) were delayed by patient-controlled analgesia with continuous epidural block.

Significance of patient-controlled analgesia in combination with continuous epidural block for patients who underwent posterior lumbar surgery.

The purpose of the study was to evaluate the efficiency of patient-controlled analgesia (PCA) combined with continuous epidural block in patients who underwent lumbar spine surgery. In group 1 (postoperative PCA group), 23 patients were administered postoperative continuous epidural block in combination with analgesics, which was self-regulated by the patient using a device. In contrast, the 22 patients in group 2 (control group) received suppositories or intramuscular injections of analgesics on request. The following factors were compared between the two groups: pain relief according to the visual analog scale for pain assessment, the frequency of administration of analgesics, and side effects of the postoperative analgesia. The patients in group 1 had more satisfactory relief of pain according to the visual analog scale for pain assessment and needed suppositories and intramuscular injection of analgesics less frequently on the 1st, 2nd, and 3rd postoperative day. The time spent by nurses on pain management in group 1 was less than that in group 2. No patient had any serious complications in either group. In conclusion, the present patient-controlled method combined with postoperative continuous epidural block could decrease the intensity of postoperative pain and the amount of time spent by nurses on the administration of postoperative analgesics after lumbar spine surgery.