The effect of solution temperature on the pain of peribulbar anesthesia

The prophylactic effect of photobiomodulation therapy on pain perception due to infiltration injection: a randomized clinical trial

OBJECTIVES

Fear of pain in dentistry especially the injection involved in most of the processes has always been an important issue preventing the patients from consulting a dentist at the right time. This study aims to evaluate the effect of photobiomodulation therapy on reduction of pain in infiltration injection.

MATERIALS AND METHODS

This trial is a crossover study including 30 patients. The patients are divided into two groups (laser therapy in the first period and placebo effect in the next period or vice versa with split-mouth design) using the covariate adaptive randomization method. All the patients received bilateral maxillary canine anesthesia in two periods performed with an ICT injection device (amount of anesthesia solution loaded: 1.8 mL) at a speed of 1 mL/min and a temperature of the solution of 37 °C. In each period, patients received either a prophylactic dose of 940-nm laser (500 mW, 10 J/cm2) or its placebo effect before the injection. The degree of pain perception after each sort of treatment is evaluated by both SEM (Sound, Eye, Motor, and Pain) and VAS (Visual Analogue Scale) scales.

RESULTS

According to analysis, all the patients scored a VAS scale under 3 in the period they received intervention. Also considering the SEM scale, most of the patients scored 0 in the intervention period. No adverse effect was reported during or after the process.

CONCLUSIONS

The study showed a significant effect of photobiomodulation on reducing pain perception during infiltration injection.

CLINICAL RELEVANCE

This method can be useful in order to lower the pain for the patients consulting a dentist and therefore facilitate consulting at early stages of the dental issues.

TRIAL REGISTRATION

The registration number (date) of the clinical trial in a Primary Registry in the WHO Registry Network is IR.ARAKMU.REC.1398.248(13/03/2020). The related URL is https://en.irct.ir/trial/45362 .

Effect of warming anesthetic on pain perception during dental injection: a split-mouth randomized clinical trial

BACKGROUND

The purpose of this study is to determine the effectiveness of warming anesthesia on the control of the pain produced during the administration of dental anesthesia injection and to analyze the role of Transient Receptor Potential Vanilloid-1 nociceptor channels in this effect.

PATIENTS AND METHODS

A double-blind, split-mouth randomized clinical trial was designed. Seventy-two volunteer students (22.1±2.45 years old; 51 men) from the School of Dentistry at the Universidad Austral de Chile (Valdivia, Chile) participated. They were each administered 0.9 mL of lidocaine HCl 2% with epinephrine 1:100,000 (Alphacaine®) using two injections in the buccal vestibule at the level of the upper lateral incisor teeth. Anesthesia was administered in a hemiarch at 42°C (107.6°F) and after 1 week, anesthesia was administered by randomized sequence on the contralateral side at room temperature (21°C-69.8°F) at a standardized speed. The intensity of pain perceived during the injection was compared using a 100 mm visual analog scale (VAS; Wilcoxon test p<0.05).

RESULTS

The use of anesthesia at room temperature produced an average VAS for pain of 35.3±16.71 mm and anesthesia at 42°C produced VAS for pain of 15±14.67 mm (p<0.001).

CONCLUSION

The use of anesthesia at 42°C significantly reduced the pain during the injection of anesthesia compared to its use at room temperature during maxillary injections. The physiological mechanism of the temperature on pain reduction could be due to a synergic action on the permeabilization of the Transient Receptor Potential Vanilloid-1 channels, allowing the passage of anesthetic inside the nociceptors.

Systematic review and meta-analysis of the effect of warming local anesthetics on injection pain

STUDY OBJECTIVE

Local anesthetics are the main class of analgesics used for pain management during laceration repair and other minor surgeries; however, they are administered by injection, which is painful. Warming local anesthetics has been proposed as a cost-free intervention that reduces injection pain. A systematic review of the effectiveness of this technique has not yet been undertaken. We determine the effectiveness of warming local anesthetics to reduce pain in adults and children undergoing local anesthetic infiltration into intradermal or subcutaneous tissue.

METHODS

We used published articles from MEDLINE (1950 to June 2010), EMBASE (1980 to June 2010), CINAHL (1982 to June 2010), the Cochrane Library (second quarter 2010), International Pharmaceutical Abstracts (1970 to June 2010), and ProQuest Dissertations and Theses database (1938 to June 2010). We included studies with randomized or pseudorandomized designs and healthy subjects or patients receiving subcutaneous or intradermal injection of local anesthetics that were warmed (body temperature) or not (room temperature). Studies of regional anesthesia and intraarticular, spinal, or periorbital administration of local anesthetics were excluded. Data were extracted onto predesigned forms and verified by 2 reviewers. Quality was assessed with the Cochrane risk of bias tool. The primary outcome was self-reported pain as assessed by a visual analog or numeric rating scale. Data were combined with mean differences with 95% confidence intervals (CIs) by using a random-effects model.

RESULTS

Twenty-nine studies were retrieved for close examination and 19 studies met inclusion criteria. A total of 18 studies with 831 patients could be included in a meta-analysis. Seventeen studies had an unclear risk of bias and 1 had a high risk of bias. A mean difference of -11 mm (95% CI -14 to -7 mm) on a 100-mm scale was found in favor of warming local anesthetics. Subgroup analysis of 8 studies investigating the effect of warming on buffered local anesthetics yielded similar results: -7 mm (95% CI -12 to -3 mm).

CONCLUSION

Warming local anesthetics leads to less pain during injection and therefore should be done before administration.

Peribulbar anesthesia for cataract surgery: effect of lidocaine warming and alkalinization on injection pain, motor and sensory nerve blockade

AIM

To compare self-reported pain and efficacy of warmed, alkalinized, and warmed alkalinized lidocaine with plain 2% lidocaine at room temperature for peribulbar anesthesia in cataract surgery.

MATERIALS AND METHODS

Through a prospective, single-blinded, randomized, controlled clinical trial 200 patients were divided into four groups. They received either lidocaine at operating room temperature 18 degrees C, control group (Group C), lidocaine warmed to 37 degrees C (Group W), lidocaine alkalinized to a pH of 7.09+/-0.10 (Group B) or lidocaine at 37 degrees C alkalinized to a pH of 6.94+/-0.05 (Group WB). All solutions contained Inj. Hyaluronidase 50 IU/ml. Pain was assessed using a 10-cm visual analog score scale. Time of onset of sensory and motor blockade and time to onset of postoperative pain were recorded by a blinded observer.

RESULTS

Mean pain score was significantly lower in Group B and WB compared with Group C (P<0.001). Onset of analgesia was delayed in Group C compared with Group B (P=0.021) and WB (P<0.001). Mean time taken for the onset of complete akinesia and supplementation required for the block was significantly lower in Group B. Time of onset of pain after operation was significantly earlier in Group W compared with Group C (P=0.036).

CONCLUSION

Alkalinized lidocaine with or without warming produced less pain than lidocaine injected at room temperature. Alkalinization enhances the effect of warming for sensory nerve blockade, but warming does not enhance alkalinization, in fact it reduces the efficacy of alkalinized solution for blocking the motor nerves in the eye.

The effect of warming local anaesthetic on the pain of injection during sub-Tenon's anaesthesia for cataract surgery

In a double blind, randomised controlled trial, we examined the effect of warming local anaesthetic solutions on the pain experienced by patients undergoing a sub-Tenon's block for cataract surgery. In all, 140 patients were randomly allocated to receive either local anaesthetic stored at room temperature (control group) or local anaesthetic warmed to 37 degrees C (study group). Pain scores were assessed using a verbal analogue scale from 0 to 10. There was no significant difference in pain scores between the two groups. We conclude that the practice of warming local anaesthetic prior to performing a sub-Tenon's block does not significantly reduce the amount of pain experienced by patients.

The use of peribulbar anaesthesia in paediatric cataract surgery (age 7-15 years) in a mobile eye camp in China

AIM

To evaluate the feasibility and acceptability of the use of peribulbar anaesthesia (PA) in paediatric cataract surgery in rural areas in China, where there are limitations in expertise and equipment for general anaesthesia (GA).

METHODS

We prospectively evaluated the feasibility and acceptability of carrying out paediatric cataract surgery under PA in children aged 7-15 years. Informed consent was obtained from the subjects and their parents. Children were assessed for their suitability for PA. Peribulbar anaesthesia was given as a peribulbar block using a 2% lidocaine, 0.5% bupivacaine-hyaluronidase mixture administered before lens aspiration with intraocular lens implantation. The acceptability of the PA was evaluated by questionnaire.

RESULTS

A total of 19 patients were recruited. Their mean age was 12 +/- 2 years (range 7-15 years). None required conversion to GA. All subjects regarded PA as either totally acceptable (63.2%) or acceptable (36.8%). The mean pain scores (from 0 to 100) during the injection and surgery were 28 +/- 26 and 6 +/- 8, respectively. Seventeen patients (89.5%) said they would prefer PA if choices in anaesthesia were offered again.

CONCLUSIONS

Peribulbar anaesthesia can be considered as a viable option in selected children undergoing cataract surgery when facilities for safe and optimal general anaesthesia are unavailable.

Techniques for reducing anesthetic injection pain

BACKGROUND

The authors conducted a study that considered family physicians' and dentists' knowledge and application of techniques to reduce the pain associated with anesthetic injections. They also assessed practitioners' discomfort with patients' injection pain and needle anxiety/phobia.

METHODS

The authors designed a questionnaire about awareness and use of 10 techniques for reducing pain of anesthetic injection and mailed it to 2,000 randomly selected family physicians and general dentists. They analyzed the data to examine differences between disciplines regarding awareness and use of techniques, reasons for not using techniques, number of injections given per week, and predictive value of certain demographic variables on reported use of individual techniques and on practitioner reactions to patients' pain and anxiety.

RESULTS

The response rate was 35 percent. The authors used the chi2 test for differences between disciplines' awareness of and use or nonuse of techniques, Wilcoxon testing to assess differences between disciplines' median values of number of weekly injections and logistic regression to study demographic variables' predictive values (P = .01). General dentists give more injections than do family physicians. Differences existed between disciplines' awareness and use of eight of 10 techniques. Disciplines reported cost and time issues as reasons for not using some techniques. Number of years in practice and age were associated with use of six techniques. Dentists reported feeling greater personal effects of patients' pain and needle anxiety/phobia than did family physicians.

CONCLUSIONS

Those not using pain-lessening techniques inaccurately identified time and cost as problems, suggesting that respondents may be less familiar with these techniques than otherwise reported. Further study is recommended.

CLINICAL IMPLICATIONS

Pain reduction techniques for anesthetic injection cost little to implement, are not time liabilities, and can lessen avoidable pain and reduce the incidence of needle phobia.

Anxiety in cataract surgery: pilot study

PURPOSE

To quantify the anxiety provoked by cataract surgery and establish whether the preoperative stage, the day of surgery, or the outcome was associated with unduly high anxiety.

SETTING

Moorfields Eye Hospital, London, United Kingdom.

METHODS

A cross-sectional survey of adult patients having cataract surgery under local anesthesia was done. The Hospital Anxiety and Depression (HAD) scale and a Visual Analog Scale (VAS) were used to quantify the patients' anxiety. Of the 108 patients enrolled, 38 were surveyed at the preassessment clinic, 36 at the day ward (operation day), and 34 at the postoperative clinic. For each stage, the patients were divided into groups: first-eye cataract surgery, second-eye cataract surgery, and combined (first- and second-surgery patients).

RESULTS

The average patient in the combined group found the preassessment stage to be more anxiety provoking than the operation day or the postoperative visit. The median HAD scale scores were 5, 4, and 2, respectively, and the median VAS anxiety scores, 4, 2, and 1.75. The HAD anxiety scores in the combined group were significantly different between the operation day and the postoperative visit (P <.05, Mann-Whitney U) but not between the preassessment and operation day. The VAS scores showed no significant differences among the 3 stages of treatment in the combined group. Different anxiety trends were found between the first- and second-surgery groups.

CONCLUSION

The average patient was not unduly anxious about cataract surgery.

A single-centre study of 1000 consecutive peribulbar blocks

PURPOSE

To assess the efficacy and safety of the peribulbar block as practised by anaesthetists in a District General Hospital and also to assess the effect of using the 'painless local' subconjunctival injection on the pain of the peribulbar block.

METHOD

Audit data collected from 1000 consecutive patients undergoing peribulbar blocks with 2% lignocaine were analysed. Efficacy was assessed by visual rating scores for operative pain, eye movement, intraocular pressure and reinjection rate, and safety by looking at complications. Comparison of pain of injection scores was used to assess the effect of the 'painless local' injection. Visual rating scores for pain were analysed using the Mann-Whitney U-test.

RESULTS

Akinesia was achieved in 79% of blocks and operative pain scores were very low (median = 0, IQR = 0). All complications recorded were minor and there were no sight- or life-threatening events. The 'painless local' injection given to 499 patients resulted in significantly lower visual rating scores for pain of injection (p<0.05).

CONCLUSION

These data suggest that the peribulbar block is a safe and effective method of providing anaesthesia for eye surgery provided that it is taught methodically and practised by experienced staff. The 'painless local' injection reduces the pain experienced during administration of this block.

The methodologic quality of clinical trials on regional anesthesia for cataract surgery

OBJECTIVE

To assess the methodologic quality of published randomized trials of regional anesthesia management strategies for cataract surgery.

DESIGN

Literature review and analysis.

METHOD

We performed a systematic search of the literature to identify all articles pertaining to regional anesthesia for cataract surgery on adults. Overall quality scores and scores for individual methodologic domains were based on the evaluations of two investigators experienced in methodologic research who independently reviewed all relevant articles using a quality abstraction form.

MAIN OUTCOME MEASURES

Study quality in each of five domains: representativeness, bias and confounding, intervention description, outcomes and follow-up, and statistical quality and interpretation.

RESULTS

Eighty-two randomized clinical trials were identified with a mean overall quality score of 44%. The mean domain scores ranged from 37% for representativeness to 58% for outcomes and follow-up. Forty percent or fewer studies received the maximum score for reporting the setting, the population, and the start and end dates; describing the inclusion and exclusion criteria; adequately randomizing subjects; and adequately masking individuals participating in the study. Key outcomes were often inadequately reported, including the distribution of patient-reported pain scores and the mean surgical time.

CONCLUSIONS

Greater attention to methodologic quality and detailed reporting of study results will improve the ability of readers to interpret the results of clinical trials assessing regional anesthesia for cataract surgery.

Synthesis of the literature on the effectiveness of regional anesthesia for cataract surgery

OBJECTIVE

To synthesize the findings of the randomized trials of regional anesthesia management strategies for cataract surgery.

DESIGN

Literature review and analysis.

METHOD

The authors performed a systematic search of the literature to identify all articles pertaining to regional anesthesia during cataract surgery on adults. One investigator abstracted the content of each article onto a custom-designed form. A second investigator corroborated the findings. The evidence supporting the anesthesia approaches was graded by consensus as good, fair, poor, or insufficient.

MAIN OUTCOME MEASURES

Evidence supporting the effectiveness of different forms of regional anesthesia.

RESULTS

There was good evidence that retrobulbar and peribulbar blocks provide equivalent akinesia and pain control during cataract surgery. Additionally, sub-Tenon's blocks were at least as effective as retrobulbar and peribulbar blocks. There was good evidence that retrobulbar block provides better pain control during surgery than topical anesthesia, and there was fair evidence that peribulbar block provides better pain control than topical anesthesia.

CONCLUSIONS

This synthesis of the literature demonstrates that currently used approaches to anesthesia management provide adequate pain control for successful cataract surgery, but there is some variation in the effectiveness of the most commonly used techniques. Data are needed on patient preferences to determine the optimal strategies for anesthesia management during cataract surgery.

Prilocaine versus lignocaine for minor lid procedures

PURPOSE

To determine whether prilocaine is a more comfortable local infiltration anaesthetic agent than the more widely used lignocaine for minor eyelid procedures.

METHODS

A prospective randomised study was undertaken to compare the discomfort between local infiltration of plain 2% prilocaine versus its equivalent, plain 2% lignocaine. One hundred and twenty-five patients were recruited. Pain was assessed subjectively using a visual analogue pain score, graded from 0 to 10.

RESULTS

The mean pain score for the prilocaine group was 1.82 compared with 3.19 for the lignocaine group. Using the Mann-Whitney U-test for significance, U = 1236.5; p < 0.001.

CONCLUSION

Prilocaine is a more comfortable local infiltration anaesthetic agent than lignocaine when used for minor eyelid procedures.

Comparison of analgesia and akinesia after retrobulbar injections at different speeds

PURPOSE

To assess how the speed of injection of local anesthetic solutions affected pain of injection, bulbar akinesia and analgesia with retrobulbar anesthesia (RBA).

METHODS

70 patients undergoing RBA for cataract surgery were enrolled in a prospective masked trial. They were allocated randomly to receive 5 ml anesthetic solution injected either within 20 seconds (group A) or within 60 seconds (group B). Additionally, akinesia of the orbicularis muscle was created according to O'Brien's technique. The pain of injection was registered on an ordinal analogue scale immediately before and after RBA. The following data were collected before and 20 minutes after retrobulbar injection: eye motility (Kestenbaum test), and corneal sensitivity (0: no sensitivity; 1: sensitivity remaining). Data were also collected on age, sex, and bulbar length, and any side effects of the intervention.

RESULTS

Injection pain did not differ in the two groups. After RBA horizontal and vertical eye motility was slightly lower in group A than group B. Persistent motility was found in 18 patients in group A and 16 in group B. Median horizontal and vertical motility was 0 mm in both groups. Four patients in group A and five in group B had corneal sensitivity persisting after RBA.

CONCLUSIONS

This comparison of different injection velocities brought to light no significant differences regarding bulbar analgesia and akinesia after RBA.

Anesthesia for cataract surgery

Developments of anesthesia for cataract surgery emerging from literature published during the scanning period include new drugs for sedation before general anesthesia and some discussion about monitoring. A few articles report on both improvements in and complications of peribulbar and retrobulbar injections. There are studies confirming the efficacy of sub-Tenon and topical anesthesia, sometimes associated with facial block. A tendency toward topical anesthesia emerged. Intraocular drug delivery was studied for toxicity both for cornea and for retina, in experimental and clinical settings.

Does warming of anesthetic solutions improve analgesia and akinesia in retrobulbar anesthesia?

PURPOSE

The authors assess the effect of warming local anesthetic solutions on pain of injection and on bulbar akinesia and analgesia of retrobulbar anesthesia (RBA).

METHODS

Seventy patients undergoing RBA for cataract surgery were enrolled in a prospective, double-blind trial. They were allocated randomly to receive 5 ml either warm (37 degrees C) or cold (20 degrees C) anesthetic solution for RBA. Additionally, O'Brien's method was used to create an akinesia of the orbicularis oculi muscle. The following data were collected before and 20 minutes after retrobulbar injection: pain of injection, eye motility (Kestenbaum test), and corneal sensitivity (0: no sensitivity; 1: sensitivity remaining) at four different sites. The pain of injection was registered using an ordinal analogous scale before and immediately after the injection. Furthermore, data acquisition included any possible side effects and the bulbar length, measured with ultrasound.

RESULTS

The score for injection pain (4.5 +/- 2.3 points), horizontal eye motility (0.2 +/- 0.8 mm), vertical eye motility (0.9 +/- 2.1 mm) all were lower for the warm group in comparison to the cold group (average pain score: 5.2 +/- 2.6 points; horizontal eye motility: 0.7 +/- 1.6 mm; vertical eye motility: 1.2 +/- 2.0 mm). Two patients in the warm group and four patients in the cold group had remaining corneal sensitivity. None of the differences were significant.

CONCLUSIONS

Data indicate no significant difference in bulbar analgesia and akinesia after RBA between injections of warm and cold anesthetic solutions.