Adult circumcision can be performed under local or regional anesthesia. Medical indications for this procedure include phimosis, paraphimosis, recurrent balanitis and posthitis (inflammation of the prepuce). Nonmedical reasons may be social, cultural, personal or religious. The procedure is commonly performed using either the dorsal slit or the sleeve technique. The dorsal slit is especially useful in patients who have phimosis. The sleeve technique may provide better control of bleeding in patients with large subcutaneous veins. A dorsal penile nerve block, with or without a circumferential penile block, provides adequate anesthesia. Informed consent must be obtained. Possible complications of adult circumcision include infection, bleeding, poor cosmetic results and a change in sensation during intercourse. (+info)
Ropivacaine or 2% mepivacaine for lower limb peripheral nerve blocks. Study Group on Orthopedic Anesthesia of the Italian Society of Anesthesia, Analgesia, and Intensive Care.
BACKGROUND: Intra- and postoperative clinical properties of sciatic-femoral nerve block performed with either ropivacaine at different concentrations or mepivacaine have been evaluated in a multicenter, randomized, blinded study. METHODS: Adult patients scheduled for foot and ankle surgery were randomized to receive combined sciatic-femoral nerve block with 225 mg of either 0.5% (n = 83), 0.75% (n = 87), or 1% (n = 86) ropivacaine, or with 500 mg of 2% mepivacaine (n = 84). A thigh tourniquet was used in all patients. Onset time, adequacy of surgical anesthesia, time to offset of nerve block, and time until first postoperative requirement for pain medication were evaluated by a blinded observer. RESULTS: The adequacy of nerve block was similar in the four treatment groups (the ratios between adequate:inadequate: failed blocks were 74:9:0 with 0.5% ropivacaine, 74:13:0 with 0.75% ropivacaine, 78:8:0 with 1% ropivacaine, and 72:12:0 with 2% mepivacaine). The onset of the block was slower with 0.5% ropivacaine than with other anesthetic solutions (P < 0.001). Regardless of the concentration, ropivacaine produced a longer motor blockade (10.5+/-3.8 h, 10.3+/-4.3 h, and 10.2+/-5.1 h with 0.5%, 0.75%, and 1% ropivacaine, respectively) than with mepivacaine (4.3+/-2.6 h; P < 0.001). The duration of postoperative analgesia was shorter after mepivacaine (5.1+/-2.7 h) than after ropivacaine (12.2+/-4.1 h, 14.3+/-5 h, and 14.5+/-3.4 h, with 0.5%, 0.75%, or 1% ropivacaine, respectively; P < 0.001). Pain relief after 0.5% ropivacaine was 14% shorter than 0.75% or 1% ropivacaine (P < 0.05). During the first 24 h after surgery, 30-37% of patients receiving ropivacaine required no analgesics compared with 10% of those receiving mepivacaine (P < 0.001). CONCLUSIONS: This study suggests that 0.75% ropivacaine is the most suitable choice of local anesthetic for combined sciatic-femoral nerve block, providing an onset similar to mepivacaine and prolonged postoperative analgesia. (+info)
Clinically safe dosage of felypressin for patients with essential hypertension.
Hemodynamic changes were evaluated in patients with essential hypertension when felypressin of various concentrations was administered. The parameters studied were systolic pressure, diastolic pressure, heart rate, left ventricular systolic phase, and endocardial viability ratio. Results showed that blood pressure tended to increase, and the value of 1/pre-ejection period2 (PEP2) tended to decrease, upon administration of 3 ml of 2% propitocaine containing 0.06 international units/ml (IU/ml) of felypressin. Significant increase of blood pressure and decrease in 1/PEP2 was noted upon administration of 3 ml of anesthetic solution containing 0.13 IU/ml of felypressin. No ischemic change of the myocardium was detected even with the highest felypressin concentration (3 ml of 2% propitocaine containing 0.25 IU/ml of felypressin). These results suggest that the clinically safe dosage of felypressin for patients with essential hypertension is approximately 0.18 IU. This amount is equivalent to 6 ml of 3% propitocaine with 0.03 IU/ml of felypressin, which is a commercially available local anesthetic for dental use. It seems that the decrease in 1/PEP2 that occurred during blood pressure increase was due to the increase in afterload caused by contraction of the arterioles. Although in the present study no ischemic change was noted, special care should be taken to prevent myocardial ischemia in patients with severe hypertension. (+info)
Prolonged diplopia following a mandibular block injection.
A case is presented in which a 14-yr-old girl developed diplopia after injection of the local anesthetic Xylotox E 80 A (2% lidocaine with 1:80,000 epinephrine). Since the complication had a relatively slow onset and lasted for 24 hr, the commonly suggested explanations based on vascular, lymphatic, and neural route theories do not adequately fit the observations. No treatment, other than reassurance, was necessary, and the patient recovered fully. (+info)
Efficacy of mandibular topical anesthesia varies with the site of administration.
This study compared the threshold of pain sensitivity in the anterior mandibular mucobuccal fold with the posterior. This was followed by a comparison of the reduction of needle insertion pain in the anterior mucobuccal fold and the pterygo-temporal depression by either topical anesthesia or nitrous oxide inhalation. The pain threshold was determined by an analgometer, a pain-measuring device that depends on pressure readings; additionally, pain caused by a needle inserted by a normal technique was assessed using a visual analog scale (VAS). The threshold of pain was significantly lower in the incisor and canine regions than in the premolar and the molar regions (P < 0.001). Compared to a placebo, topical anesthesia significantly reduced the pain from needle insertion in the mucobuccal fold adjacent to the mandibular canine (P < 0.001), but did not significantly reduce pain in the pterygotemporal depression. The addition of 30% nitrous oxide did not significantly alter pain reduction compared to a control of 100% oxygen. These results suggest that topical anesthesia application may be effective in reducing the pain of needle insertion in the anterior mandibular mucobuccal fold, but may not be as effective for a standard inferior alveolar nerve block. The addition of 30% nitrous oxide did not lead to a significant improvement. (+info)
Anti-ganglioside antibodies can bind peripheral nerve nodes of Ranvier and activate the complement cascade without inducing acute conduction block in vitro.
The neurophysiological effects of nine neuropathy-associated human anti-ganglioside antisera, three monoclonal antibodies to ganglioside GM1 (GM1) and of the cholera toxin B subunit (a GM1 ligand) were studied on mouse sciatic nerve in vitro. GM1 antisera and monoclonal antibodies from patients with chronic motor neuropathies and Guillain-Barre syndrome, and GQ1b/ disialosyl antisera and monoclonal antibodies from patients with chronic ataxic neuropathies and Miller Fisher syndrome were studied. In vitro recording, for up to 6 h, of compound nerve action potentials, latencies, rise times and stimulus thresholds from isolated desheathed sciatic nerve was performed in the presence of antiganglioside antibodies and fresh human serum as an additional source of complement. No changes were observed over this time course, with 4-6 h values for all electrophysiological parameters being within 15% of the starting values for both normal and antibody containing sera and for the cholera toxin B subunit. Parallel experiments on identically prepared desheathed nerves performed with 0.5 nM saxitoxin led to complete conduction block within 10 min of application. Under identical conditions to those used for electrophysiological recordings, quantitative immunohistological evaluation revealed a significant increase in IgM (immunoglobulin M) deposition at nodes of Ranvier from 5.3+/-3.1% to 28.7+/-8.4% (mean+/-SEM) of desheathed nerves exposed to three normal and three antibody containing sera, respectively (P < 0.03). Complement activation was seen at 100% of normal and 79% of disease-associated IgM positive nodes of Ranvier. These data indicate that anti-ganglioside antibodies can diffuse into a desheathed nerve, bind to nodes of Ranvier and fix complement in vitro without resulting in any overt physiological deterioration of the nerve over 4-6 h. This suggests that the node of Ranvier is relatively resistant to acute antiganglioside antibody mediated injury over this time scale and that anti-ganglioside antibodies and the cholera toxin B subunit are unlikely to have major direct pharmacological effects on nodal function, at least in comparison with the effect of saxitoxin. This in vitro sciatic nerve model appears of limited use for analysing electrophysiologically the effects of anti-ganglioside antibodies on nerve function, possibly because its short-term viability and isolation from circulating systemic factors do not permit the evolution of an inflammatory lesion of sufficient magnitude to induce overt electrophysiological abnormalities. In vivo models may be more suitable for identifying the effects of these antibodies on nerve conduction. (+info)
Conduction block in carpal tunnel syndrome.
Wrist extension was performed in six healthy subjects to establish, first, whether it would be sufficient to produce conduction block and, secondly, whether the excitability changes associated with this manoeuvre are similar to those produced by focal nerve compression. During maintained wrist extension to 90 degrees, all subjects developed conduction block in cutaneous afferents distal to the wrist, with a marked reduction in amplitude of the maximal potential by >50%. This was associated with changes in axonal excitability at the wrist: a prolongation in latency, a decrease in supernormality and an increase in refractoriness. These changes indicate axonal depolarization. Similar studies were then performed in seven patients with carpal tunnel syndrome. The patients developed conduction block, again with evidence of axonal depolarization prior to block. Mild paraesthesiae were reported by all subjects (normals and patients) during wrist extension, and more intense paraesthesiae were reported following the release of wrist extension. In separate experiments, conduction block was produced by ischaemic compression, but its development could not be altered by hyperpolarizing currents. It is concluded that wrist extension produces a 'depolarization' block in both normal subjects and patients with carpal tunnel syndrome, much as occurs with ischaemic compression, but that this block cannot be altered merely by compensating for the axonal depolarization. It is argued that conduction slowing need not always be attributed to disturbed myelination, and that ischaemic compression may be sufficient to explain some of the intermittent symptoms and electrodiagnostic findings in patients with carpal tunnel syndrome, particularly when it is of mild or moderate severity. (+info)
Respiratory effects of low-dose bupivacaine interscalene block.
In this double-blind study, interscalene brachial plexus (ISBP) block was performed in 11 volunteers using 10 ml of either 0.25% (n = 6) or 0.5% (n = 5) bupivacaine with epinephrine 1:200,000. Diaphragmatic excursion, respiratory function and neural function were assessed for 90 min. Our results showed that hemidiaphragmatic excursion declined significantly after block in the 0.5% group and paradoxical movement during inspiration was more common than in the 0.25% group. Forced vital capacity and forced expiratory volume in 1 s declined significantly in the 0.5% group (mean 74.6 (SD 13.0)% and 78.2 (19.9)% of baseline, respectively) but not in the 0.25% group. Sensory anaesthesia in the upper limb was found consistently in both groups, although biceps paralysis occurred earlier after 0.5% bupivacaine. We conclude that ISBP block using 10 ml of 0.25% bupivacaine provided upper limb anaesthesia to pinprick in C5-6 dermatomes with only occasional interference with respiratory function. (+info)