Abstract
Background
Thermal ablation, usually performed with tumescent local anaesthesia (TLA), is the preferred method for varicose veins treatment. Tumescent local anaesthesia is always cited; however, little detail of the procedure is presented in publications. This retrospective audit of clinical tumescent local anaesthesia practice aims to provide detailed information on an important aspect of endovenous practice.
Methods
Patients who underwent three types of endothermal treatment (Venefit, Radiofrequency Induce Thermal Therapy and Endovenous Laser Ablation) to a single saphenous trunk using tumescent local anaesthesia were assessed. Differences in tumescent local anaesthesia volume per unit length of treated vein were assessed for the followings: type of saphenous trunk, length of vein treated, effect of additional phlebectomy and bilateral versus interval unilateral treatment for bilateral veins. Descriptive data are reported as mean and standard deviation, and groups were compared using the one-way ANOVA test.
Results
Between 2008 and 2014, single-saphenous-trunk ambulatory TLA thermal ablation was performed in 979 patients, mean age was 54 years. A total of 1229 limbs had truncal ablations and synchronous phlebectomy was performed in 470 limbs. No tumescent local anaesthesia-related complications occurred. There was no significant difference in standardised tumescent local anaesthesia volume per centimetre (ml) used for the three devices. Tumescent local anaesthesia volume per centimetre (ml) differed significantly between saphenous trunks. On average, a standard 10–12 ml/cm of tumescent local anaesthesia was used for saphenous trunks. Mean total tumescent local anaesthesia volume per patient, when treating the great saphenous vein alone, was 931 ml for bilateral and 425 ml for unilateral treatment.
Conclusion
This report of over 1000 endovenous procedures demonstrates safe performance of laser and radiofrequency treatments using tumescent local anaesthesia. Although no attempt was made to determine minimum volume requirements, a mean tumescent local anaesthesia volume of 10–12 ml/cm administered to the perivenous space provides adequate anaesthesia for truncal saphenous ablation.
Introduction
Ambulatory endovenous thermal ablation is the preferred method for treating varicose veins of saphenous trunk origin and is recommended by UK’s NICE as first choice for treatment of suitable varicose veins.1–3 Much has been written on thermal ablation therapies with focus on types of energy generator (predominantly lasers and radiofrequency) and differences in applicator catheters. However, the tumescent local anaesthesia (TLA) on which all endothermal therapies depend is frequently cited but rarely afforded detailed consideration in publications. Whilst a superficial search of publication databases for “tumescent local anesthesia” and “phlebology” might produce a number of hits (e.g. PubMed: 14 hits for articles published between 2007 and 2016), these comprise a combination of reviews, small studies of surgery, laser and powered phlebectomy, and TLA mention in papers on non-thermal non-tumescent techniques. None address the substance, technical or clinical aspects of TLA. One paper does report on total TLA volumes injected but is limited by small numbers. There is no detailed information available on TLA technique or consideration of TLA volumes for differing saphenous trunks in endovenous practice and only one small paper has published data on TLA volumes. 4 A 10 mm radius of TLA fluid around the target vessel or a minimum volume of 10 ml/cm of vein has been advocated but not evidenced in one commercial literature. 5 A few TLA factors that have previously been investigated include influence of TLA fluid temperature, effect of bicarbonate buffering and effect of antegrade or retrograde TLA fluid delivery.6–8
TLA has its origins in plastic surgery, in liposuction procedures, when large TLA fluid volume is injected to induce tumescence (tissue engorgement with fluid), as reported by Klein in 1985. 9 Endovenous experience with TLA dates back to the early 2000s, with the introduction of thermal ablation procedures into clinical practice. Effective delivery of peri-venous TLA solution achieves anaesthesia and vein compression with apposition of the vein wall to the catheter. This also acts as a heat-sink, protecting adjacent structures such as nerves and skin from thermal injury.
Pioneers of endovenous therapy delivered TLA by repeated hand injection of 20 ml syringe volumes. Manual injection has been superseded in the last decade by more ergonomic electromechanical pumps. Many protocols for the formulation of tumescent anaesthetic solution exist with the most common diluent being 0.9% saline and containing variable concentrations of local anaesthetic (typically Lidocaine and Prilocaine) with or without adrenaline. Sodium bicarbonate (8.4%) solution may be added to neutralise the pH. Although unlikely to be exceeded, it is wise to use the patient’s weight to calculate maximum allowable dose of the selected local anaesthetic and to ensure against inadvertent intra-procedural overdose even when large TLA volumes are used. There is no evidence of superiority for the local anaesthetic agent used for TLA beyond their toxicity differences (Table 1).
Maximum dosage of commonly used local anaesthetic agents in mg per kg and per 70 kg man, and preparations with and without adrenaline 1:200,000.
Whilst is may seem obvious to state that the amount of TLA fluid needed is “enough to compress the vein and provide adequate insulation”, actual data on TLA practice is lacking. The aim of this paper is to provide detailed data on TLA volumes (and corresponding LA dosages) from over 1000 procedures to act as a point of reference and to inform on this often skirted area of endovenous practice. This report aspires to aid beginners who find TLA to be particularly challenging.
Methods
Contemporaneous records of all patients who underwent ambulatory thermal ablation therapy with TLA by a single experienced endovenous surgeon using his published technique were assessed. 10 Three types of ablation therapy were used during the studied period as follows: Endovenous Laser Ablation (EVLA, Biolitec 810 nm laser system®, biolitec AG, Vienna, Austria), Venefit (Venefit, Closurefast, VNUS Medical Technologies, Inc., Sunnyvale, CA) and Radiofrequency Induce Thermal Therapy (RFiTT®; Olympus, Hamburg, Germany). This report is informed by peri-procedural data collected on a prospectively maintained database and interrogated with particular reference to TLA volumes in patients who had treatment to only one saphenous trunk per limb. Limbs where more than one saphenous trunk was treated were excluded. However, bilateral limb treatment was included provided only a single saphenous trunk had been treated in each limb. Treatments were performed in four hospitals in Worcestershire. Patients were offered synchronous phlebectomy when funded (two private hospitals) but not in two public hospitals.
When performed, phlebectomy was undertaken using local injection of the TLA solution, without administration of additional LA. No foam sclerotherapy was performed in this group of patients. Treated legs were dressed by application of a rolled dressing pad (Zetuvit® E, Hartmann, Paul-Hartmann-Stasse 12, Heidenhelm, Germany) over the treated vein to capture TLA liquid escape and secured with Pehahaft compression bandaging (Selles Medical Ltd, Hull, East Yorkshire, UK). Bandages were exchanged for thigh-length RAL class II compression stockings after 48 h. All procedures were ambulatory and patients were discharged home within 30 min of returning to the ward, with instructions advising immediate and frequent ambulation. No analgesia was prescribed, but patients were advised to take over-the-counter analgesics should these be required and to return to work when they felt it was appropriate.
TLA procedure
Administration of TLA followed the same protocol at all hospital sites with the only difference being TLA volume delivered. This was influenced by patient-related factors such as bodily habitus, the length of vein treated and, when phlebectomy was performed, the number and size of the varices. TLA infusion of 500 mg of Prilocaine (50 ml vial of Citanest, AstraZeneca UK Ltd, Macclesfield, Cheshire) and 20 ml of 8.4% bicarbonate in 1000 ml of 0.9% saline (without adrenaline) was made up at room temperature by the scrub nurse immediately prior to commencing the procedure.
After on-table vein cannulation at the most distal refluxing site, the applicator catheter was introduced and advanced to the relevant saphenous junction. Patients were then placed in Trendelenburg’s position (10–15°) to facilitate vein emptying. A long 22G needle attached to sterile flexible tubing with injection driven by a foot-pedal controlled electromechanical pump (VNUS Medical Technologies, Inc., 5799 Fontanoso Way, San Jose) was used for TLA infiltration. Pump flow rate was adjusted to inject at 30–50% depending on patient comfort. Injection was performed under direct ultrasound visualisation with the probe held longitudinal to catheter (in the direction of injection with the non-injecting hand) to allow visualisation of tumescent delivery beyond the immediate site of injection. When required additional sterile sonic gel was used to aid duplex imaging during the TLA fluid placement.
To minimise patient discomfort, injection was commenced at the (previously anaesthetised) site of cannulation and progressed cranially, with careful attention to patient’s reactions, until good placement of TLA fluid had been achieved (Figure 1).
Duplex ultrasound image showing the endovenous device applicator and vein with surrounding TLA fluid in longitudinal (a) and transverse (b) views.
One important practical technique that helps to minimise needle puncture (and maximise fluid injected via each puncture) was achieved by making the initial skin and fascia entry at a steep angle for commencement of injection. The needle was then partially withdrawn (out of fascia without exiting the skin) and then placed at shallower angles to more proximal parts of the vein to deliver more TLA fluid to more cranial aspects of the vein (Figures 2 and 3). This, together with remote “stripping” of perivenous tissue by the pump pressure, minimised skin puncturing. Another effective ploy to improve patient comfort was to place a small amount of TLA fluid sub-dermally (via the previous puncture) at the intended site of the next skin puncture site. Care was taken to achieve a minimum 10 mm depth of TLA fluid between the vein and skin in thin patients.
Clinical picture (a) and corresponding duplex ultrasound image (b) showing the long TLA needle inserted through skin (clinical) and fascia (duplex) at a relatively steep angle during TLA injection.
Picture (a) and corresponding duplex image (b) showing the long needle after partial withdrawal (out of fascia without exiting the skin) and then reinsertion at a shallow angle to more proximal parts of the vein.
Whilst occasional vein puncture cannot be avoided, care was taken not to inject directly into the vein. TLA injection is a craft, and duplex and clinical judgement was used to determent sufficiency of tumescent delivery. The importance of reconfirming position of the catheter tip after TLA administration (and prior to thermal ablation) should also be emphasised because the catheter tip rarely remains in its pre-TLA administration position.
The saphenous trunk length treated and TLA volume used per limb were recorded. Other variables recorded included type of thermal ablation therapy, length of treated vein, whether phlebectomy was undertaken, and for bilateral veins, bilateral versus interval unilateral ablation. TLA volume per centimetre of treated vein, total TLA volume per limb and per patient were calculated and used for comparisons. To eliminate the impact of phlebectomy and vein type on TLA, only great saphenous veins (GSVs) treated without phlebectomy were used when comparing thermal ablation devices. Intra-procedural pain scores were not assessed in this retrospective audit.
Statistical analysis
Data were tabulated onto a Microsoft Excel® spreadsheet (Microsoft, California, USA), and statistical analyses were performed using GraphPad Software Inc® (GraphPad, La Jolla, California, USA). Descriptive data were reported as mean (standard deviation (SD)), groups were compared using the one-way ANOVA test and p values were computed with significance level set at 0.05.
Results
Between 2008 and 2014, single-saphenous-trunk ambulatory LA thermal ablation was performed in 979 patients with mean age of 54 years (range 18–89) and 565 (58%) were women. Overall, there were 1035 treatment episodes with 1229 truncal ablations (including bilaterals) (Table 2). Synchronous phlebectomy was performed in 470 limbs. Target truncal veins were GSV 935 (76%), small saphenous vein (SSV) 227 (18.5%) and anterior accessory saphenous vein (AASV) 67 (5.5%). Mean preoperative vein diameter, measured 10 cm from the proximal reflux site on standing, was 7 mm (range 4–22 mm).
Patient demographics and limb and treatment categories studied.
CEAP: clinical, etiology, anatomy, pathophysiology.Note: The majority were women undergoing treatment for unilateral, primary varicose veins for C2 symptoms.
Safety outcomes
All thermal ablation procedures and phlebectomies were successfully completed. For clinical assessment of safety for any complication that might have been directly related to the TLA injection or the thermal ablation intervention no TLA-related complications occurred in the peri- or post-operative period. Specifically, no patients complained of excessive discomfort or vagal reaction during TLA administration. No injection site haematoma or ecchymosis presented as a problem and there were no skin burns in any limbs treated in this study. Further, no clinically significant haematoma or bruising was reported in relation to the truncal ablations on follow-up. The following complications were reported or identified: seven limbs developed circumferential bandage abrasion, five limbs had self-limiting phlebectomy stab site-related paraesthesia as follows: all five incidences of paraesthesia occurred within the field of the saphenous nerve but to a variable extent. The proximal aspect of distribution was always related to a stab incision used for phlebectomy. Five limbs had inflammation localised to phlebectomy stab sites.
Thermal ablation device
Device-related outcomes are shown in Tables 3 and 4. Mean length of treated GSV was greatest for Venefit-treated limbs (p < 0.05); however, there was no significant difference in standardised TLA volume (ml/cm) used for the three devices. Approximately, 11 ml/cm was used with each device.
Thermal ablation (Venefit, EVLA and RFITT) procedures showing patient numbers and limb breakdown by treatment type (unilateral versus bilateral, and for bilaterals: synchronous and interval treatments).
EVLA: Endovenous Laser Ablation; RFITT: Radiofrequency Induce Thermal Therapy.
Mean GSV length treated and volume of TLA per centimetre of vein for Venefit, EVLA and RFITT.
EVLA: Endovenous Laser Ablation; RFITT: Radiofrequency Induce Thermal Therapy; GSV: great saphenous vein; SD: standard deviation.
Note: Mean GSV lengths differed significantly between groups, *P < 0.05. However, there was no difference in the volume of TLA per centimetre of GSV between groups, P = 0.675.
Saphenous trunk treated
For comparison of saphenous trunks, only limbs without phlebectomy were assessed (Table 5). Unsurprisingly, treated vein length (and vein diameter) differed significantly between the three saphenous trunks with GSV being longest and having greatest diameter, P < 0.05. Standardised TLA volume (ml/cm) also differed significant between trunks with AASV being highest.
Saphenous trunks showing treated vein lengths and volumes of TLA per centimetre of vein for GSV, AASV and SSV treatments (without phlebectomy).
GSV: great saphenous vein; SSV: small saphenous vein; AASV: anterior accessory saphenous vein.
Note: Mean vein lengths and mean vein diameters differed significantly between the three saphenous trunks, *P < 0.05. There was also a significant difference in unit volumes (TLA volume per centimetre treated) between GSV, SSV and AASV, *P < 0.05.
Unilateral versus bilateral treatment
Total TLA volume (and corresponding LA dosage) per patient episode was assessed for unilateral and bilateral treatments (without phlebectomy). Expectedly, mean TLA volume (SD) in patients undergoing bilateral treatment (931 ml (163 ml), mean GSV length per limb of 34.4 cm) was almost double the TLA volume used for unilateral treatments (425 ml (131 ml), mean GSV length per limb of 35.5 cm), P < 0.05. With TLA volumes containing 500 mg of Prilocaine per litre, this translated to a mean Prilocaine dose of 465.5 mg for bilateral and 212.5 mg for unilateral treatments.
Impact of phlebectomies
Comparison was made for total TLA treatment volumes per limb that had truncal ablation without phlebectomies (759 limbs) and those where synchronous phlebectomy had been performed (470 limbs). Mean (SD) TLA volume per limb of 371 ml (117 ml) without phlebectomy differed significantly from when phlebectomy had been performed when TLA volume was 527 ml (132 ml), P < 0.05.
Discussion
This paper provides detailed information of TLA procedures, as performed by the author, and addresses many of the practicalities of TLA injection essential for safe delivery of ambulatory endovenous thermal therapy. Mean TLA volume used for unilateral treatment of 425 ml was less than half the amount used by Kendler et al. who used 852 TLA ml/patient (250–1470 ml) in their study of 51 limbs in 50 patients undergoing Venefit. 4 Perhaps, this data represented their learning curve.
Unsurprisingly, highest mean TLA volumes (931 ml) and Prilocaine dose (465.5 mg) in this report were in patients having bilateral treatment. Whilst these doses are near the toxicity levels of Prilocaine (at physiological body weight), they are significantly lower than doses used by plastic surgeons in liposuction procedures when typical TLA volumes and Lidocaine doses of up to 4000 ml and 1250 mg (well in excess of normal toxic doses) are used. 11 However, fluid is aspirated during liposuction and indeed only small rises in serum LA have been reported after liposuction treatment. 11 Reassuringly, much lower TLA volumes (and LA doses well below toxic levels) were used in unilateral endovenous treatment.
Adrenaline is variably used in endovenous TLA (routine in liposuction) to slow systemic absorption of LA. It affords additional safety against LA toxicity; however, this is rarely an issue in endovenous treatments. Despite this, clinicians should be aware of the importance of the safety doses of LA with and without adrenaline (Table 1) and consideration should be given to treating bilaterals as single legs on separate occasions (interval unilaterals) when there are toxicity concerns in for example thin patients with extensive varicosities. No adrenaline was used in TLA in the series reported.
This report shows that approximately 10–12 ml/cm of TLA solution correctly delivered into the perivenous intrafascial space provides adequate anaesthesia for laser and radiofreqency endovenous thermal therapies. This supports the recommendation made in commercial literature for RFA. 5 Careful placement of TLA eliminates burn injuries that are otherwise reported at rates of up to 2% in contemporary literature.12–15
This knowledge of a typical standardised TLA volume and the practical details described may allow rational planning of endovenous treatments and may be especially useful for clinicians starting endothermal venous practice. For example, a 500 ml TLA solution rather than a 1000 ml could be prepared when the target vein is known to be less than say 40 cm and when no phlebectomies are planned. This report also shows that phlebectomy can be effectively performed using TLA injection alone, without need for additional LA or sedation. Although dependent on number and site of varicosities, it was noteworthy that, on average, the additional TLA volume used when phlebectomy was performed was approximately equal to that used for the truncal thermal ablation procedure. Again, consideration needs to be given to toxicity levels if extensive phlebectomies are planned. Use of cold TLA solutions has been described; however, this author has no personal experience of this aspect of the TLA technique. The theory that knowledge of differing operating temperatures for individual thermal ablation devices (Venefit – 120°C, RFITT – 60–100°C and up to 700°C for bare fibre EVLA) might have influenced TLA volumes through an unconscious tendency to administer more TLA fluid for higher-temperature devices was considered. However, there was no difference in standardised TLA volume (ml/cm) for the three devices studied as used by this operator.
Limitations of the study
This observational audit does not claim originality nor was it a controlled study with a defined experimental hypothesis. Many vascular centres could have provided similar data; however, they have not. This report is derived from a retrospective review of a single surgeon’s clinical preferences and practice and has the expected limitations and potential risks of bias inherent in all case series. The paper should be read and interpreted in this light. Specific to this is the fact that although factors such as device type and saphenous trunk were examined and compared, this data should be interpreted from the perspective of the non-randomised, non-prospective study that it is. However, providing this detailed report on TLA volumes and LA dosages use in an established endovenous practice does give a point of reference for clinicians wishing to start endothermal venous therapy even if this might be considered a vague scientific endpoint for publication. Availability of information on TLA mixtures, technique and practice (as used by this practitioner) may be of practical use to clinicians. However, readers should note that no attempt was made intentionally to compare one volume with another at the outset and indeed one can never be sure whether too much TLA was given than might have been necessary. However, the important safety aspect in TLA, to give enough for the procedure to be safely completed, was accomplished.
Conclusion
TLA can be used for ambulatory endovenous thermal ablation (and phlebectomy) at mean TLA volumes of approximately 10–12 ml/cm. This paper presents clinical data from normal practice that establishes a reference for the TLA component that is commonly cited in modern varicose veins treatment but for which published data is conspicuously scarce. In so doing, no claims of originality of technique are made. It is hoped that novice endovenous practitioners will find this as a useful practical resource.
Footnotes
Acknowledgements
I would like to thank the many theatre staff and junior doctors who contributed to the data collection and my colleague Stephen J Goodyear for his help in finalising the paper.