Comparison of technical and block characteristics of different combined spinal and epidural anesthesia techniques.

BACKGROUND AND OBJECTIVES: The combined spinal and epidural (CSE) technique can reduce or eliminate some of the disadvantages of spinal and epidural anesthesia, while still preserving their advantages. CSE anesthesia is now commonly performed with a single-segment needle-through-needle technique; however, this technique involves some controversies about needle handling and the risk of catheter migration. To avoid some of these potential problems, special CSE sets have been produced. In the present study, 2 of these sets were compared with the traditional double-segment technique. METHODS: Ninety patients undergoing orthopedic surgery of the lower extremity were randomly allocated into 3 groups of equal size: Group 1, CSE set with an interlocking device between the spinal and epidural needle; group 2, CSE set with a "backeye" at the epidural needle curve for the passage of the spinal needle; group 3, double-segment technique. All epidural needles were 18-gauge, and spinal needles were 27-gauge with a pencil-point tip. In groups 1 and 2, the puncture was performed at the L3-4 interspace, and in group 3 the epidural catheter was first inserted at the L2-3 interspace followed by spinal puncture one interspace lower. Hyperbaric 0.5% bupivacaine, 2 mL, was used for the spinal block, and 4 mL of 2% lidocaine with epinephrine through the epidural catheter was used as a test dose. The block performance characteristics were recorded, and the level of analgesia was studied in a blinded fashion. Postoperatively, a bolus of epidural morphine 2 to 4 mg was used for the control of postoperative pain. All patients were interviewed on the 1st and the 7th postoperative days. Afterwards, the needles and catheters were examined by microscopy. RESULTS: The frequency of the successful CSE block was higher in groups 3 (100%) and 2 (90%) than in group 1 (63%) (P <.05). The mean duration of successful block performance, as well as the median level of analgesia, were similar in all the groups. One case of epidural catheter migration intrathecally was observed (group 1). Postoperative nausea and vomiting occurred in 23% of patients, and the incidence of postdural puncture headache was 2.2%. The incidence of backache at the puncture site was similar in the groups. Microscopy showed 6 distorted spinal needle tips (all in group 1), but no material damage to the epidural catheters. CONCLUSIONS: The use of the CSE sets does not seem to save time compared with the double-segment technique. Technical problems, unsuccessful CSE block, and damaged spinal needle tip were noted relatively often with the interlocking CSE set. Anesthetic characteristics in the successful blocks were similar with the different techniques.

Comparison of three catheter sets for continuous spinal anesthesia in patients undergoing total hip or knee arthroplasty.

BACKGROUND AND OBJECTIVES: Continuous spinal anesthesia (CSA) with microcatheters may be complicated because of technical problems. In elderly patients, some of the problems may be solved by using thicker catheters. A recent invention, involving a catheter-over-needle system, may prevent leakage of cerebrospinal fluid (CSF) and may also improve the prediction of the intrathecal position of the catheter tip. METHODS: This study included 90 patients undergoing primary hip or knee replacement, randomly allocated into 3 groups, with 30 patients in each group: Group EC, a 24-gauge epidural catheter through a 19-gauge Tuohy needle; group MC, a 28-gauge microcatheter through a 22-gauge spinal needle; group SC, a 22-gauge spinal catheter over a 27-gauge spinal needle through an epidurally placed 18-gauge Crawford needle. All subarachnoid catheterizations were performed with the patient in the lateral position and the initial spinal block dose was 2 mL of plain 0.5% bupivacaine. Increments of 0.5 mL were administered when required. The block performance characteristics were recorded, and the level of analgesia was studied in a blinded fashion. Catheter function during the postoperative infusion was assessed. Afterwards the needles and catheters were examined by microscopy. RESULTS: The frequency of the successful catheterization was higher in the EC and MC groups (90% in each) than in the SC group (63%) (P <.05). The mean duration of the successful catheterizations, as well as the median level of analgesia, were similar in the groups. The postoperative infusion had to be stopped in 3, 1, and 1 patients in groups EC, MC, and SC, respectively, because of a technical reason. No neurologic sequelae occurred in this study. Microscopy showed 4 distorted spinal needle tips (2 each with MC and SC) and minor material damage of the SC catheters when bone had been met during block performance. CONCLUSIONS: Placement of the SC catheters was unsuccessful to a high degree, and bone contact produced distortion of the tip of some of these catheters. Otherwise, the quality associated with catheterization time, anesthetic distribution, and catheter function was similar with the 3 catheters.

Technical aspects and postoperative sequelae of spinal and epidural anesthesia: a prospective study of 3,230 orthopedic patients.

BACKGROUND AND OBJECTIVES: Major complications after spinal or epidural anesthesia are extremely rare. The occurrence of less serious and transient sequelae and complaints may be underestimated if there is no established organization for the systematic and continuous surveillance of patients after anesthesia. This study was designed to evaluate the possible relationship between various block-related occurrences and the intra- and postoperative side effects and complaints. METHODS: This prospective study included 3,230 orthopedic patients operated on under neuraxial block. The block was performed by single-dose (single-shot spinal anesthesia [SPIN], 80.6%), continuous spinal anesthesia (CSA, 10.3%), or combined spinal and epidural anesthesia (CSE, 9.1%) technique. The patient position during surgery and a detailed description of block performance and equipment, as well as all intraoperative problems, were immediately recorded. Every patient was given a standardized questionnaire to be completed and returned after 1 week. RESULTS: The overall incidence of paresthesia was 12.8%, being most frequent during spinal catheter insertion with multiple attempts. Postoperative sensory disturbances (numbness, dysesthesia) occurred unrelated to paresthesia elicited by the puncture or catheterization. The failure rates (SPIN, 1.0%; CSA, 1.5%; and CSE, 1.0%) were quite low. Asystole with successful resuscitation, occurred in 1 patient with CSE but, overall, hemodynamic perturbations were more common with the continuous techniques. On the first postoperative day, decreased sensation of the skin was significantly more frequent after the continuous techniques, still present in 6.5% of SPIN patients, 6.1% of CSA patients, and 17.2% of CSE patients 1 week after surgery. These disturbances were also related to the use of a tourniquet and lateral position of the patient during surgery. The frequency of postdural puncture headache (PDPH) was similar for the different techniques (SPIN, 0.9%; CSA, 1.5%; and CSE, 1.7%). About one third of the patients reported strong postoperative pain on the day after the operation, and 5.6% continued to report this at 1 week. CONCLUSIONS: Although sensory changes were quite frequent, they were mild and transient. Rather than having been caused by the anesthetic technique, per se, a "nonanesthetic" reason (position, tourniquet, immobilization) should also be considered as their origin. Sensory disturbances, as well as strong pain for at least a week, were reported by several patients, and to become aware of these problems and improve the quality of treatment, a universal regional anesthesia follow-up system is recommended.

Microscopic analysis of three different spinal needle tips after experimental subarachnoid puncture.

BACKGROUND AND OBJECTIVES: Previous studies have shown the vulnerability of the tips of cutting type thin spinal needles and the possibility of foreign material passing into the subarachnoid space during the lumbar puncture. We made a microscopic analysis to compare two commonly used noncutting pencil-point spinal needles with different tip designs. Needles with a cutting tip design were included as reference. METHODS: Four fresh cadavers were placed in the lateral position and their backs were scrubbed with disinfectant solution containing 0.1% fluorescein. Thirty-two spinal needles (27 gauge) of each type (modified Quincke, modified Sprotte, and modified Whitacre) were inserted through an introducer at interspaces L2-5 into the subarachnoid space. Under visual control (spinal canal opened ventrally) all the needle tips were cut after successful subarachnoid puncture; 16 needles of each tip design were investigated under a fluorescence microscope, and another 16 needle tips were collected into test tubes and cytocentrifuged smears were prepared. The tips and smears with the most obvious findings were photographed under a microscope. RESULTS: On microscopy, only 2 needle tips were damaged (1 modified Quincke and 1 modified Whitacre). Visible fluorescent tissue particles were more frequently seen on modified Quincke needles (56%) compared with modified Sprotte (37%) and Whitacre (37%) needles (NS). In the cytocentrifugation smears, the largest clusters of epithelioid cells and muscle fibers were observed in the Quincke group. In the Whitacre group many fewer and smaller cell clusters including small muscle particles were seen, and only minor epithelioid cells were found in the Sprotte group. CONCLUSIONS: Tissue coring seems to be a common phenomenon during lumbar puncture. The most prominent attachments appeared with a cutting Quincke-type spinal needle.

Comparison of double-hole and single-hole pencil-point needles for spinal anesthesia with hyperbaric bupivacaine.

BACKGROUND AND OBJECTIVES: The use of thin single-hole pencil-point (SHPP) spinal needles may be a reason for subarachnoid maldistribution of local anesthetic. A new double-hole pencil-point (DHPP) needle may be preferable because of a theoretic more uniform initial distribution of local anesthetic. METHODS: This was a prospective, double-blinded study of 50 patients randomly selected to have spinal anesthesia using either single-hole 27-gauge (B. Braun, Melsungen, Germany) or double-hole 26-gauge (A.L.B. Medical Inc., U.S.A.) pencil-point needles. The former were inserted with the side port directed caudally and the latter with openings in both caudal and cranial direction. Two milliliters of hyperbaric 0.5% bupivacaine were injected in 1 minute, and sensory and motor block were studied at regular intervals during spinal anesthesia. All patients were interviewed on the first (personal) and the seventh (mailed questionnaire) postoperative day. Furthermore, microscopic inspection of the spinal needles was performed. RESULTS: There were no statistically significant differences in sensory or motor block levels between the two needle types at any time during spinal anesthesia. Likewise, there was no difference in the duration of spinal block. The postanesthetic side effects (headache, backache, pricking, numbness, weakness) were similar in both groups. Light and electron microscopic examination showed resistance of the SHPP needles to tip damage. On the other hand, the DHPP needle tips seemed to be distorted quite frequently, and, even in unused needles, the tip was blunt and asymmetric. CONCLUSION: There was no difference between the spread of analgesia using either SHPP or DHPP spinal needles. The DHPP needles appear to be vulnerable to tip damage from mechanical contact.

Comparison of postanesthetic sequelae after clinical use of 27-gauge cutting and noncutting spinal needles.

BACKGROUND AND OBJECTIVES: The tips of the bevels of thin spinal needles may be easily damaged by bony contact during puncture attempts. In this respect and also because they are less traumatic by design, noncutting, pencil-point-tip needles may be beneficial. A prospective clinical comparison of postanesthetic effects of the use of 27G Quincke-type and pencil-point spinal needles was therefore performed. METHODS: The study included 400 spinal anesthesia patients, in 200 of whom the initial needle was a 27-gauge Quincke type, a 27-gauge pencil-point needle being used in the other 200. Altogether, 464 needles had to be used; in 30 cases the pencil-point needle was replaced by a 27- or 25-gauge Quincke-type needle. A block performance form was filled in, and the patients were interviewed personally on the first postoperative day and by means of a mailed questionnaire on the 14th day. RESULTS: The tips of the Quincke-type needles were distorted in a blunt, bent or hooked manner in 13% of the initial and 14% of the final needles. The severity of the damage was related to the count category of bony contacts during puncture (0, 1-4, or 5 or more). The occurrence of postdural puncture headache was not, however, related either to damage of the needles or to the number of puncture attempts. Diffuse (not posture-dependent) headache occurred more often after the use of the Quincke-type needle than after use of the pencil-point needles, the tips of which remained intact in each case. CONCLUSION: Postanesthetic sequelae, including postdural puncture headache (overall incidence 2.5%), were not related to the shape of the spinal needles or to the damage of the Quincke-type needles.