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At least 109 records · Page 6Linked to original sources
PubMed2002

Peripheral nerve blocks for postoperative analgesia.

Peripheral nerve blocks are used as part of a preemptive and multimodal analgesic technique to provide safe and effective postoperative pain management with minimal side effects. They are used for a variety of surgical procedures in both inpatient and outpatient settings. Peripheral nerve blocks have resulted in shorter recovery times, decreased anesthesia-related complications, and better postoperative pain management. Peripheral nerve blocks, as part of a multimodal analgesic regimen, have decreased recovery times by lessening side effects (e.g., nausea, vomiting, drowsiness). Nerve blocks have allowed procedures previously performed only in hospitals to be performed on an outpatient basis by providing extended surgical area analgesia. The use of peripheral nerve blocks, however, requires skilled and knowledgeable clinicians. This article discusses the mechanism of action and the role of peripheral nerve blocks in multimodal analgesia, as well as perioperative nursing implications and management for upper and lower extremity peripheral nerve blocks.

Analgesia↗
PubMed1973

Pressure effect on the membrane action of a nerve-blocking spin label.

A reversible nerve-blocking spin label, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) was used to study the nature of anesthetic-binding sites in nerve membranes as a function of pressure. The nerve-blocking effect of TEMPO is enhanced under pressure. At atmospheric pressure, TEMPO blocks nerve conduction by solubilizing in the apolar region of the nerve membrane. However, the nerve-conduction-block by TEMPO at 150 atm of helium was related to the binding of TEMPO to a pressure-induced high-affinity polar site in the nerve membrane. The new TEMPO-binding site could not be detected in lipid model membranes and, thus, the involvement of membrane protein in the new site was inferred. Pressure may induce a nerve membrane conformation change in the presence of TEMPO. The observation that under different pressure, a single anesthetic, i.e., TEMPO, was capable of blocking nerve conduction by binding to two different sites within the nerve membrane, supports the view that there are multiple anesthetic receptor sites, which differ in chemical composition and location within the nerve membrane. These sites, when occupied by different classes of anesthetics, produce the general phenomenon of nerve-conduction block. The enhancement of nerve-conduction block by pressure may be due to the increased concentration of TEMPO in the new site in the nerve membrane under pressure.

Action Potentials↗
PubMed1991

[A report on 107 cases of obturator nerve block].

The obturator nerve passes in close proximity to the inferolateral bladder wall. Transurethral resection of bladder tumors close to these areas may stimulate the obturator nerve, causing violent adductor contraction and possible inadvertent bladder perforation. To avoid this reaction, local anesthetic blockade of the obturator nerve as it passes through the obturator canal is effective to stop adductor spasm during spinal anesthesia. We performed obturator nerve block in 107 cases by use of insulated needle and nerve stimulator, and measured the depth of the obturator nerve and that of the pubic tubercle. Obesity index was positively correlated with the depth of the obturator nerve as well as the pubic tubercle. However, no correlation was found between the obesity index and the difference of the depth of the obturator nerve and the depth of the pubic tubercle. It is suggested that if the needle is advanced in the direction of the obturator canal about 40mm further after reaching the pubic tubercle, the needle reaches the obturator nerve.

Adult↗
PubMed2005

Effect of neurolytic nerve block on systemic carrageenan-induced inflammatory response in mice.

BACKGROUND: Local tissue inflammation caused by injury or inflammatory processes may be reduced by section or local anaesthetic block of the nerve innervating the inflamed area. METHODS: Using a neurolytic nerve block, we assessed the systemic inflammatory response elicited by a local injection of carrageenan in mice. Sixty mice received a unilateral sciatic nerve block with 70% ethanol followed 5 days later by an injection of carrageenan on the ipsilateral or contralateral hind paw. Whole blood was sampled 15 h after carrageenan injection. RESULTS: Fifty-six animals had a complete nerve block. Tumour necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta) and interleukin 10 (IL-10) concentrations were measured in the plasma of 20 mice (10 in the ispilateral group and 10 in the contralateral group). In the remaining 36 mice (18 in each group), blood was cultured for 24 h in the presence of lipopolysaccharide or Staphylococcus aureus extract. TNF-alpha and IL-1beta production in the supernatant were, on average, 30% lower in the ispilateral group than in the contralateral group. CONCLUSION: A prolonged nerve block decreases the systemic consequences of the local inflammatory reaction elicited by carrageenan injection.

Anesthetics↗
PubMed2005

Anatomical considerations of the pediatric ilioinguinal/iliohypogastric nerve block.

BACKGROUND: The ilioinguinal/iliohypogastric nerve block is safe, effective and easy to perform in order to provide analgesia for a variety of inguinal surgical procedures in pediatric patients. A relatively high failure rate of 10-25% has been reported, even in experienced hands. The aim of this study was to determine the exact anatomical position of the ilioinguinal and iliohypogastric nerves in relation to an easily identifiable constant bony landmark, the anterior superior iliac spine (ASIS) in neonates and infants. The current ilioinguinal/iliohypogastric nerve block techniques were also evaluated from an anatomical perspective. METHOD: Dissections were performed on a sample of 25 infant and neonatal cadavers (mean weight = 2.2 kg; mean height = 45.6 cm). The distance from the ASIS to both the ilioinguinal and iliohypogastric nerves, on a line connecting the ASIS to the umbilicus was carefully measured using a digital caliper. Three techniques, commonly used in clinical practice, were simulated on the anatomical specimens. RESULT: The left and right ilioinguinal nerves were closer to the ASIS than previously described, i.e. 1.9 +/- 0.9 mm (mean +/- sd) and 2.0 +/- 0.7 mm, respectively. The mean distance from the left and right iliohypogastric nerves to the ASIS are 3.3 +/- 0.8 mm and 3.9 +/- 1.0 mm, respectively. CONCLUSIONS: We suggest that the high failure rate of the ilioinguinal/iliohypogastric nerve block in this age group could be due to lack of specific spatial knowledge of the anatomy of these nerves in infants and neonates. This cadaver-based study suggests an insertion point closer to the ASIS, approximately 2.5 mm (range: 1.0-4.9) from the ASIS on a line drawn between the ipsilateral ASIS and the umbilicus.

Cadaver↗
PubMedDate not supplied

Comparison of intraoral and percutaneous approaches for infraorbital nerve block.

OBJECTIVE: The infraorbital nerve block is frequently used during repair of facial lacerations; both percutaneous and intraoral approaches are used. The authors compared the two techniques for pain of administration and anesthetic effectiveness. METHODS: A prospective, randomized, single-blind, crossover study was conducted using 12 healthy volunteers, aged 25-41 years. No patient had prior experience with infraorbital nerve anesthesia, lidocaine allergy, active oral/facial infection, or previous facial fractures. Bilateral infraorbital nerve blocks were done using the intraoral technique on one side and the percutaneous technique on the other. Both techniques were used by the same investigator and were carried out with 27-gauge needles and 2.5 mL of 2% buffered lidocaine at room temperature injected over 20 seconds. The oral mucosa was topically anesthetized with viscous lidocaine for 1 minute prior to intraoral injection. The orders of the blocks and sides of the face anesthetized were randomized. Pain of injection, anesthetic efficacy (anesthesia of upper lip), time to anesthetic onset, and duration of anesthesia were evaluated. RESULTS: By visual-analog pain scale scores, there was less pain by the intraoral approach, although this difference did not achieve significance (p = 0.08). Overall, nine of the 12 subjects considered the intraoral technique less painful than the percutaneous approach (p = 0.14). The intraoral approach produced upper-lip anesthesia in 12 of 12 subjects, versus nine of 12 for the percutaneous technique (p = 0.25). The duration of anesthesia was longer with the intraoral approach (1.6 +/- 0.8 hours versus 0.9 +/- 0.4 hours) than with the percutaneous approach (p = 0.04). The two techniques were similar in times to anesthetic onset. CONCLUSION: The intraoral approach to the infraorbital nerve block after adjunctive topical anesthesia appeared at least as effective in producing upper-lip anesthesia as the percutaneous approach without adjunctive topical anesthesia. Although the volunteers subjectively preferred the intraoral approach and visual-analog pain scores were lower for this approach, these differences did not achieve statistical significance. The intraoral approach was associated with a longer duration of upper-lip anesthesia.

Adult↗
PubMed1995

Relation between functional deficit and intraneural local anesthetic during peripheral nerve block. A study in the rat sciatic nerve.

BACKGROUND: During peripheral nerve block, local anesthetic (LA) penetrates within and along the nerve to produce the observed functional deficits. Although much is known about the kinetics and steady-state relation for LA inhibition of impulse activity in vitro in isolated nerve, little is known about the relation between functional loss and intraneural LA content in vivo. This study was undertaken to investigate the relation of functional change to intraneural LA. METHODS: A sciatic nerve block was performed in rats with 0.1 ml 1% lidocaine radiolabeled with 14C. The total intraneural uptake of LA was determined at different times after injection, and the distribution of lidocaine along the nerve was assayed at different stages of functional block. Drug content was also compared with equilibrium lidocaine uptake in the isolated rat sciatic nerve. RESULTS: Total intraneural lidocaine in vivo increased to near steady-state in about 3 min, stabilizing at approximately 14.3 nmol/mg wet tissue for about 12 min before decreasing to zero at 70 min after injection. Although intraneural lidocaine was 1.6% of the injected dose during full block, only 0.3% was left when deep pain sensation returned and 0.065% was still detected when functions fully recovered. Despite these large differences in total lidocaine content, the longitudinal distribution remained constant. Intraneural lidocaine concentrations obtained at full block and partial recovery could be achieved in vitro by equilibration in 0.7-0.9 and 0.2-0.3 mM lidocaine, respectively. CONCLUSIONS: During peripheral nerve block only a small amount of injected LA penetrates into the nerve. The intraneural content of LA correlates with the depth of functional block.

Animals↗
PubMed1984

Treatment of chronic pain with nerve blocks and stimulation.

Nerve blocks and impulse augmentation represent two relatively noninvasive somatic procedures of use in the treatment of some chronic pain patients. In this paper the author outlines the clinical evidence for these procedures and the nature of the procedures. The author argues for their usefulness in modulating pain and their place within a more complete multi-disciplinary program.

Afferent Pathways↗
PubMed2005

Localized electrical nerve blocking.

Localized electrical nerve blocking was investigated in computer simulation and in vivo trials for sinusoidal frequencies between 5 and 20 kHz. Computer simulations indicated that a localized transmission block of the axons could occur in each of the axon models. An approximation of nerve stimulation was derived from individual axon simulations conducted over axon diameters of 5-15 microm and electrode to axon distances of 0.25 to 2.0 mm. Examination of the membrane voltage and ionic gate potentials indicated that the block could be attributed to an elevated membrane voltage. The elevated membrane voltage could prevent conduction of action potentials through the region of the sinusoidal currents. At lower amplitudes, the sinusoidal current could stimulate the axon and generate a continuous series of action potentials. In vivo trials demonstrated that the sinusoidal frequencies of greater than 10 kHz would cause a localized block in rats. Sinusoidal frequencies below 5 kHz would lead to a reduction in muscle force that appeared to be caused by depletion of transmitter at the neuromuscular junction. As indicated by the computer models of rat nerves, the endplate depletion block occurred at a lower frequency (below 5 kHz) than the block (above 10 kHz). A partial block of the axon was demonstrated, suggesting that sinusoidal currents could be used to provide selective stimulation if they are combined with distal electrical stimulation.

Action Potentials↗
PubMed1994

Intercostal nerve block.

The intercostal nerve block is an effective and relatively safe intervention for postoperative pain control after upper abdominal and thoracic surgery. It may be done in the operating room or in the PACU. Understanding the mechanics of the technique can help to improve care of patients receiving this intervention.

Humans↗
PubMed1981

Wrist and digital nerve blocks.

Wrist and digital nerve blocks are useful for the management of many common problems of the hands and fingers, including fractures, lacerations, and infections requiring drainage. The principal nerves in the wrist (radial, median, and ulnar), and the digital nerves in the hand or fingers are anatomically superficial. They can be easily located and are accessible for percutaneous injection of anesthetic agents such as lidocaine (Xylocaine), bupivacaine (Marcaine), and mepivacaine (Carbocaine). Careful selection of the anesthetic agent and type of nerve block can provides safe and effective anesthesia for many surgical procedures of the hands and fingers.

Anesthetics, Local↗
PubMed1997

Treatment of external urethral sphincter hypertonicity by pudendal nerve block using phenol solution in patients with spinal cord injury.

We report our experience utilizing the technique of phenol block of the pudendal nerve in the treatment of voiding dysfunction due to hypertonicity of the external urethral sphincter. We have performed 13 pudendal nerve blocks using a 7% phenol solution in seven patients with spinal cord injury who could not obtain relaxation of the external urethral sphincter with a large postvoid urine residual (150 ml to 600 ml) despite large doses of antispasticity drugs and intermittent catheterisations over three weeks. These drugs were discontinued at least 48 hours before this procedure. The efficacy of the pudendal nerve block could also be tested by the ease of facilitating micturition during or just after the block and measuring the amount of postvoid residual urine and intravesical leak pressure. A pudendal nerve block was produced by injecting a 7% phenol solution medial to the ischial tuberosity having specifically localized the nerve by electrical stimulation. This procedure improved the voiding pattern dramatically, leading to a full stream of urine and a remarkable decrease of postvoid residual volume and intravesical leak pressure. The mean difference of the postvoid residual volume and the intravesical leak pressure before and after pudendal nerve block was 255.7 ml and 57.5 cmH2O, respectively. We conclude that pudendal nerve block with a phenol solution as a treatment of external urethral sphincter hypertonicity was effective, easy to perform, and had no complication. This treatment should be considered as a possible alternative to more invasive surgical procedures.

Adult↗
PubMed2004

Leg weakness is a complication of ilio-inguinal nerve block in children.

BACKGROUND: Ilio-inguinal nerve block is commonly used in children to provide analgesia after surgery in the groin. Several case reports and clinical studies have described leg weakness after this technique and suggest that it may caused by inadvertent femoral nerve block. No prospective studies describing the incidence of this complication have been published. METHODS: We carried out a prospective, observational study to find out how many children had leg weakness after ilio-inguinal nerve block. We studied 200 children having day-case surgery in the groin under a general anaesthetic with an ilio-inguinal nerve block. All children performed a simple leg-raising test with each leg before induction of general anaesthesia with a standardized ilio-inguinal nerve block on the side of surgery. When the child was awake and comfortable after surgery, they repeated the leg-raising test. RESULTS: Sixteen of 182 children (8.8%) had leg weakness after surgery on the side of the nerve block only, as detected by a leg-raising test. CONCLUSIONS: Leg weakness consistent with a femoral nerve block occurs after ilio-inguinal nerve block in approximately one in nine children.

Ambulatory Surgical Procedures↗
PubMed1996

[Venous surgery of the lower limb: value of nerve blocks].

The author describes his experience of 152 cases of saphenous veins surgery performed under sciatic and femoral blocks. These nerves were located by a nervestimulation. Femoral nerve was blocked under the inguinal ligament; the sciatic nerve is blocked by the posterior approach, at the buttocks. 152 patients, 136 cases were considered satisfactory: patients felt comfortable during and after the surgery; the stripper got up the vein more easily because of the vasoplegia; very good haemodynamic stability during changes in positioning; excellent nociceptive protection during the surgery. Sixteen cases were not satisfactory: the patient couldn't overcome his anxiety; the anaesthesiologist made technical mistakes; unbearable pain at the infero-internal face of the knee during the stripping. Considering these results, the blocks of the lower extremity could be an alternative to other anaesthetic techniques.

Adult↗
PubMed1999

Selective lumbar spinal nerve block, a review.

Selective spinal nerve block is a useful tool in today's multidisciplinary approach to the diagnosis and treatment of low back pain. The indications, sources of spinal pain, block technique, result interpretation, complications and clinical applications relevant to the subject are discussed. The value of a spinal nerve block relies on an understanding of the pain elements in the back, nerve innervations and careful patient selection. If the technique is performed properly and the results are interpreted cautiously, selective spinal nerve block may prove helpful, especially for patients from whom diagnostic information is inadequate. In some cases, therapeutic effect including that from surgical intervention can be achieved selectively at the symptomatic root. However, controversy remains and therefore well designed clinical studies are needed to provide more information about the validity of this diagnostic and therapeutic modality.

Back Pain↗