565322 research-article2014
JHS0010.1177/1753193414565322Journal of Hand Surgery (European volume)Cousins et al.
JHS(E)
Full Length Article
Arm versus forearm tourniquet for carpal tunnel decompression – Which is better? A randomized controlled trial
The Journal of Hand Surgery (European Volume) 2015, Vol. 40E(9) 961–965 © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1753193414565322 jhs.sagepub.com
G. R. Cousins, S. L. Gill, C. G. Tinning, S. M. Johnson and P. K. Rickhuss Abstract Tourniquet pain is a common source of complaint for patients undergoing carpal tunnel decompression and practice varies as to the tourniquet position used. There is little evidence to suggest benefit of one position over another. Our aim was to compare patient and surgeon experience of forearm and arm tourniquets. Following a power calculation, 100 patients undergoing open carpal tunnel decompression under local anaesthetic were randomized to either an arm or a forearm tourniquet. Measurements of blood pressure, heart rate and pain were taken at 2.5 min intervals. The operating surgeon also provided a visual analogue scale rating for the extent of bloodless field achieved and for any obstruction caused by the tourniquet. There was no statistically significant inter-group difference in patient pain or physiological response, tourniquet time, bloodless field or length of procedure. The degree of obstruction caused by the tourniquet was significantly higher in the forearm group. Level of Evidence: I. Prospective Randomized Controlled Trial Keywords Carpal tunnel decompression, tourniquet, tourniquet position, forearm tourniquet Date received: 13 January 2014; revised: 25 November 2014; accepted: 29 November 2014
Introduction Carpal tunnel decompression (CTD) is the most commonly performed procedure in hand surgery (Yiannakopoulos, 2004). Clinical experience suggests that upper limb pain, secondary to tourniquet use, is a common source of complaint for patients undergoing CTD under local anaesthetic (Bidwai et al. 2013). The mechanism of this pain is complex. Mechanical stimuli, such as muscle squeezing, may cause pain through the activation of nociceptors. While there is evidence to suggest that ischemia alone is insufficient to affect nociceptor response, the mechanical stimulation of nociceptors may be sensitized by hypoxia. Pain may also result from the direct pressure exerted on nerve endings (Mense and Gerwin, 2010). Both arm and forearm tourniquets are used for haemostasis in open carpal tunnel releases. Evidence for the benefit of one over the other is conflicting in the literature. Predominantly non-clinical trials using volunteers have suggested that forearm tourniquets are better tolerated (Hutchison and McClinton, 1993; Maury and Roy, 2002). Clinical trials have, however, as yet to
show any statistically significant difference between arm and forearm tourniquet (Edwards et al. 2000; Odinsson and Finsen, 2002). There were limitations to these studies, including being under powered, lack of randomization and not taking into account factors such as physiological response and surgeon satisfaction. Our aim was to assess patient and surgeon preference for arm versus forearm tourniquets at open carpal tunnel release.
Method A power calculation was performed with a view to detecting an inter-group difference of 10 points Department of Orthopaedics and Trauma, Ninewells Hospital, Dundee, UK Corresponding author: G. R. Cousins, Department of Orthopaedics and Trauma, Level 5, Ninewells Hospital, Dundee DD1 9SY, UK. Email: [email protected]
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
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The Journal of Hand Surgery (Eur) 40(9)
(minimal clinically important difference) in the patient global numerical pain score. A total of 100 patients undergoing open CTD under local anaesthetic with tourniquet use under the care of the senior author (PKR) were recruited to the study. Patients who declined to participate in the study due to pre-existing expectations relating to tourniquet position or previous (contralateral) experience were excluded. At the beginning of the study, 50 cards labelled ‘arm’ and 50 cards labelled ‘forearm’ were placed in 100 identical envelopes. The 100 cards were also numbered, 0–100. The patients were randomized to either the arm or the forearm group (50 patients each) by the random selection of one of the envelopes at the time of preoperative consultation with the surgical team. The number on the card became the patient’s unique study identification number, allowing for the anonymous storage of data. The envelope was opened by either the senior author (PKR) or the operating surgeon (GRC, SLG, CGT, SMJ) prior to the procedure. One of the four operative surgeons in addition to the senior author was present during each procedure. The non-operating surgeon took charge of data collection. No patient received any sort of sedation or anxiolytic. Each patient received local anaesthetic (5 ml 1% plain lidocaine with 5 ml 0.5 mg/ml levobupivacaine) infiltration to the operative field at the site of intended incision prior to tourniquet application. A 60 cm long and 11 cm wide reusable tourniquet was applied to the upper arm or forearm as dictated by the randomization. The tourniquet was inflated following elevation of the limb, skin preparation and extremity draping. Tourniquet pressure was set at 250 mmHg. A numerical rating scale ranging from zero (indicating no discomfort whatsoever) to 100 (indicating severe pain sufficient to precipitate release of the tourniquet) was used during the procedure to quantify level of pain caused by the tourniquet. Participants’ understanding of the scoring system was checked immediately prior to the surgical procedure. During the procedure the patient was asked by the non-operative surgeon (with no blinding of the operating surgeon), to verbally indicate the level of discomfort relating to the tourniquet using a numerical rating scale at 2.5 min post tourniquet inflation and every subsequent 2.5 min interval throughout the procedure. The non-operative surgeon was not blinded to the tourniquet position. The change in mean patient pain score for each group was calculated by the difference between the pain score measured at 2.5 min post tourniquet inflation and the final pain score prior to tourniquet deflation. At the end of the procedure, the patient was asked to provide an overall numerical pain score (0–100) for the tourniquet site during the procedure, with zero communicating no pain whatsoever and 100 indicating
the most severe pain. The patient marked this on a 100 mm visual analogue scale (VAS). This data provided subjective measurements of patient discomfort every 2.5 min during the procedure, as well as a global assessment of their pain at the end of the procedure. Blood pressure and heart rate were also recorded at 2.5 min post tourniquet inflation and every subsequent 2.5 min interval throughout the procedure. Blood pressure was subsequently converted to mean arterial pressure (MAP) during data analysis. This data provided two objective measures of patient discomfort during the procedure. The operating surgeon was asked to provide subjective scores using a VAS (scale 0–100) for both the extent of bloodless field (zero being a completely bloodless field and 100 indicating significant bleeding that made completing the procedure impossible). The level of obstruction experienced by surgeon during the procedure, such as impediment of the surgeon’s movement or visual field secondary to the tourniquet was also recorded (zero being no impediment whatsoever and 100 indicating significant obstruction that made completing the procedure impossible). These were recorded as VASs. All 100 patients entering the study completed the study. As all assessment was completed intra-operatively; there was no loss to follow-up.
Statistical analysis Histograms were used to assess for normality of distribution. Age, tourniquet time, pulse and MAP were normally distributed. Changes in pulse, systolic blood pressure, diastolic blood pressure and MAP were also normally distributed. Between-group comparisons of age and tourniquet time were made using Student’s t test. This was also used to make betweengroup comparisons of changes from 2 to 8 min in pulse and MAP. Pearson’s Chi-square test was used to analyse VAS for pain from 2 to 8 min. To examine the changes over the entire recording period, repeated measurements of data were analysed using generalized estimating equations. Chi-squared test was used to compare gender in the groups. Ethical approval was granted for this study by the East of Scotland Ethics Committee.
Results The patient demographics and tourniquet times are displayed in Table 1. There were no statistically significant differences in age, gender or tourniquet time. The mean patient-reported pain score, heart rate and MAP were charted over time (Figure 1, Table 2). There was no statistically significant difference in the
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
963
Cousins et al. Table 1. Inter-group patient demographics (age and gender) and mean procedural tourniquet time. Tourniquet position:
Arm
Forearm
Statistical significance (p value)
Mean age (years) Age range (years) Gender (M:F) Mean tourniquet time (minutes) Tourniquet time range (minutes)
53 32–82 16:34 8.2 2–12
54 30–80 13:37 8.9 4–13
0.641 – 0.509 0.740 –
45 40
Mean pain score (0-100)
35 30 25
forearm arm
20 15 10 5 0
2
4
Time (Mins)
6
8
Figure 1. Mean patient numerical pain score at each 2.5 min interval post tourniquet inflation.
change of heart rate or MAP throughout the procedure between the groups for any of these parameters (Table 2). The median global numerical patient pain score taken at the end of the procedure showed no statistical difference between the two groups (arm = 30; forearm = 23; p = 0.959). The median VAS values recorded by the operating surgeon demonstrated that there was no significant difference in the extent to which a bloodless field was achieved (arm = 10, forearm = 10; p = 0.918; Figure 2). However, in one case in the upper arm group the tourniquet was deflated at 3 min due to uncontrolled bleeding. It was thought that the tourniquet might be contributing to a venous tourniquet effect. The procedure was completed without tourniquet. There was a significant difference in the median VAS values recorded by the operating surgeon for obstruction caused by the tourniquet; the forearm tourniquet caused significantly more obstruction as compared with the upper arm tourniquet (upper arm
= 2; forearm = 10; p = 0.001; Figure 3). The number of arm and forearm cases performed by each surgeon was approximately the same.
Discussion This prospective, randomized and statistically powered study failed to show a statistically significant difference in the level of tourniquet-related pain experienced by patients undergoing CTD using an arm or forearm tourniquet. These results would support previous research from Yousif et al. (1993), Odinsson and Finsen (2002) and Edwards et al. (2000), which also assert that there was no significant relationship between tourniquet position and tourniquet-related patient discomfort. The trial by Yousif et al. (1993) investigated tolerance to arm and forearm tourniquet through randomization of 40 subjects to either group. In addition, they reported on the experience of 18 patients who underwent a
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
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The Journal of Hand Surgery (Eur) 40(9)
Table 2. Mean change in patient heart rate and mean arterial pressure over course of procedure. Mean change in pain parameter over course of procedure
Tourniquet position: Arm
Forearm
Statistical significance (p value)
Heart rate (bpm) Mean arterial pressure (MAP) (mmHg);
−0.2 (SE 1.4) −0.4 (SE 1.6)
−3.1 (SE 1.3) −1.7 (SE 1.7)
0.128 0.587
30
25
Frequency
20
Forearm Arm
15
10
5
0 0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100
Extent of Bloodless Field (0-100) Figure 2. Histogram of surgeon-reported extent of bloodless field (0–100; 0 = minimum blood; 100 = maximum blood).
45 40 35
Frequency
30
Forearm Arm
25 20 15 10 5 0 0-9
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99
100
Extent of Surgeon Obstruction (0-100) Figure 3. Histogram of surgeon-reported obstruction of surgical field (0–100; 0 = minimum obstruction; 100 = maximum obstruction).
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
965
Cousins et al. clinical procedure with forearm tourniquet. The article by Odinsson and Finsen (2002) specifically looked at carpal tunnel syndrome and similarly found no difference. However, this article was underpowered and had a wide range of tourniquet time from 6–37 min. Edwards et al. (2000) conducted a prospective trial comparing upper arm and forearm tourniquet for hand surgery under local anaesthetic and suggested no difference in patient experience. Their trial was not randomized and did assess surgeon preference. However, it was adequately powered with 100 patients in each group. A retrospective study (Glynn et al. 2005) of 74 patients that had undergone CTD suggested that forearm tourniquet was well tolerated, but no direct comparison was made with arm tourniquet. A non-clinical trial by Hutchison and McClinton (1993) on 20 volunteers found that forearm tourniquet was tolerated for an average of 45% longer and no participant tolerated an arm tourniquet longer than a forearm tourniquet. This finding was supported by a randomized trial of 24 volunteers (Maury and Roy, 2002) in which forearm tourniquet was tolerated on average 7 min longer than arm tourniquet. This would suggest that a key factor in tourniquet tolerance is duration. The previous studies that have demonstrated a significant difference have done so with average tourniquet times greater than 20 min, which is much longer than the tourniquet times in this series (Table 1). Ogufere et al. (1995) suggested that tourniquet pain is more due to individual idiosyncrasies rather than tourniquet duration if the inflation time was 20 mins or less. The pain scores (which were clearly defined as pain relating to the tourniquet) varied so little in our study that we could not determine any correlating factors, including heart rate and blood pressure. This is contrary to Hutchison and McClinton (1993) who found that blood pressure correlated with pain. Our results also confirm that there is no difference in the extent of bleeding in the surgical field achieved by a tourniquet set at 250 mmHg placed on the forearm as compared with the arm, as measured by a subjective VAS score given by the operating surgeon. Our study did however produce a statistically significant difference in the level of obstruction experienced by the operating surgeon in relation to the position of the tourniquet. This must be understood on the basis that no inter-surgeon variability analysis was performed (as it was felt the operating surgeon would have no bearing on the primary aim of determining levels of pain from the tourniquet. The VAS score relating to obstruction was significantly higher (worse) in the forearm group as compared with the arm group (median arm = 2; median forearm = 10; p = 0.001; Figure 3). As previously discussed, this did
not, however, result in a significant difference in tourniquet time between the two groups (Table 1). In summary, this randomized trial of arm versus forearm tourniquet positioning in CTD has shown no statistically significant difference in subjective (numerical rating scale) and objective (heart rate, MAP) measures of patient discomfort. It remains reasonable for surgeons to select tourniquet position based upon their individual preference. Acknowledgements Linda Cochrane, Statistician University of Dundee.
Conflict of interests None declared.
Ethical approval East of Scotland Research Ethics Service (EoSRES) Research Ethics Committee 2. Approval for study granted 6 February 2012. REC reference 11/ES/0047.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors
References Bidwai AS, Benjamin-Laing HE, Shaw DA, Iqbal S, Jones WA, Brown DJ. Patient satisfaction with tourniquet application and local anaesthesia infiltration in carpal tunnel decompression and the relationship with overall satisfaction. J Plast Surg Hand Surg. 2013, 47: 481–3. Edwards SA, Harper GD, Giddins GE. Efficacy of forearm versus upper arm tourniquet for local anaesthetic surgery of the hand. J Hand Surg Br. 2000, 25: 573–4. Glynn A, Strunk S, Reidy D, Heines DE. Carpal tunnel release using local anaesthetic and a forearm tourniquet. Ir Med J. 2005, 98: 144–5. Hutchinson DT, McClinton MA. Upper extremity tourniquet tolerance. J Hand Surg. 1993, 18-A: 206–10. Maury AC, Roy WS. A prospective, randomized, controlled trial of forearm versus upper arm tourniquet tolerance. J Hand Surg Br. 2002; 27: 359–60. Mense S, Gerwin RD. Muscle pain: understanding the mechanisms. Berlin-Heidelberg, Springer Verlag, 2010: 77–8. Odinsson A, Finsen V. The position of the tourniquet on the upper limb. J Bone Joint Surg Br. 2002, 84: 202–4. Ogufere WE, Giddins GEB, Thom JS. Upper arm tourniquet in local anaesthetic surgery. J Hand Surg Br. 1995, 20: 413–4. Yiannakopoulos CK. Carpal ligament decompression under local anaesthesia: the effect of lidocaine warming and alkalinisation on infiltration pain. J Hand Surg. 2004, 29B: 32–4. Yousif NJ, Grunert BK, Forte RA, Matloub HS, Sanger JR. A comparison of upper arm and forearm tourniquet tolerance. J Hand Surg Br. 1993, 18: 639–41.
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
JHS0010.1177/1753193414565322Journal of Hand Surgery (European volume)Cousins et al.
JHS(E)
Full Length Article
Arm versus forearm tourniquet for carpal tunnel decompression – Which is better? A randomized controlled trial
The Journal of Hand Surgery (European Volume) 2015, Vol. 40E(9) 961–965 © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1753193414565322 jhs.sagepub.com
G. R. Cousins, S. L. Gill, C. G. Tinning, S. M. Johnson and P. K. Rickhuss Abstract Tourniquet pain is a common source of complaint for patients undergoing carpal tunnel decompression and practice varies as to the tourniquet position used. There is little evidence to suggest benefit of one position over another. Our aim was to compare patient and surgeon experience of forearm and arm tourniquets. Following a power calculation, 100 patients undergoing open carpal tunnel decompression under local anaesthetic were randomized to either an arm or a forearm tourniquet. Measurements of blood pressure, heart rate and pain were taken at 2.5 min intervals. The operating surgeon also provided a visual analogue scale rating for the extent of bloodless field achieved and for any obstruction caused by the tourniquet. There was no statistically significant inter-group difference in patient pain or physiological response, tourniquet time, bloodless field or length of procedure. The degree of obstruction caused by the tourniquet was significantly higher in the forearm group. Level of Evidence: I. Prospective Randomized Controlled Trial Keywords Carpal tunnel decompression, tourniquet, tourniquet position, forearm tourniquet Date received: 13 January 2014; revised: 25 November 2014; accepted: 29 November 2014
Introduction Carpal tunnel decompression (CTD) is the most commonly performed procedure in hand surgery (Yiannakopoulos, 2004). Clinical experience suggests that upper limb pain, secondary to tourniquet use, is a common source of complaint for patients undergoing CTD under local anaesthetic (Bidwai et al. 2013). The mechanism of this pain is complex. Mechanical stimuli, such as muscle squeezing, may cause pain through the activation of nociceptors. While there is evidence to suggest that ischemia alone is insufficient to affect nociceptor response, the mechanical stimulation of nociceptors may be sensitized by hypoxia. Pain may also result from the direct pressure exerted on nerve endings (Mense and Gerwin, 2010). Both arm and forearm tourniquets are used for haemostasis in open carpal tunnel releases. Evidence for the benefit of one over the other is conflicting in the literature. Predominantly non-clinical trials using volunteers have suggested that forearm tourniquets are better tolerated (Hutchison and McClinton, 1993; Maury and Roy, 2002). Clinical trials have, however, as yet to
show any statistically significant difference between arm and forearm tourniquet (Edwards et al. 2000; Odinsson and Finsen, 2002). There were limitations to these studies, including being under powered, lack of randomization and not taking into account factors such as physiological response and surgeon satisfaction. Our aim was to assess patient and surgeon preference for arm versus forearm tourniquets at open carpal tunnel release.
Method A power calculation was performed with a view to detecting an inter-group difference of 10 points Department of Orthopaedics and Trauma, Ninewells Hospital, Dundee, UK Corresponding author: G. R. Cousins, Department of Orthopaedics and Trauma, Level 5, Ninewells Hospital, Dundee DD1 9SY, UK. Email: [email protected]
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
962
The Journal of Hand Surgery (Eur) 40(9)
(minimal clinically important difference) in the patient global numerical pain score. A total of 100 patients undergoing open CTD under local anaesthetic with tourniquet use under the care of the senior author (PKR) were recruited to the study. Patients who declined to participate in the study due to pre-existing expectations relating to tourniquet position or previous (contralateral) experience were excluded. At the beginning of the study, 50 cards labelled ‘arm’ and 50 cards labelled ‘forearm’ were placed in 100 identical envelopes. The 100 cards were also numbered, 0–100. The patients were randomized to either the arm or the forearm group (50 patients each) by the random selection of one of the envelopes at the time of preoperative consultation with the surgical team. The number on the card became the patient’s unique study identification number, allowing for the anonymous storage of data. The envelope was opened by either the senior author (PKR) or the operating surgeon (GRC, SLG, CGT, SMJ) prior to the procedure. One of the four operative surgeons in addition to the senior author was present during each procedure. The non-operating surgeon took charge of data collection. No patient received any sort of sedation or anxiolytic. Each patient received local anaesthetic (5 ml 1% plain lidocaine with 5 ml 0.5 mg/ml levobupivacaine) infiltration to the operative field at the site of intended incision prior to tourniquet application. A 60 cm long and 11 cm wide reusable tourniquet was applied to the upper arm or forearm as dictated by the randomization. The tourniquet was inflated following elevation of the limb, skin preparation and extremity draping. Tourniquet pressure was set at 250 mmHg. A numerical rating scale ranging from zero (indicating no discomfort whatsoever) to 100 (indicating severe pain sufficient to precipitate release of the tourniquet) was used during the procedure to quantify level of pain caused by the tourniquet. Participants’ understanding of the scoring system was checked immediately prior to the surgical procedure. During the procedure the patient was asked by the non-operative surgeon (with no blinding of the operating surgeon), to verbally indicate the level of discomfort relating to the tourniquet using a numerical rating scale at 2.5 min post tourniquet inflation and every subsequent 2.5 min interval throughout the procedure. The non-operative surgeon was not blinded to the tourniquet position. The change in mean patient pain score for each group was calculated by the difference between the pain score measured at 2.5 min post tourniquet inflation and the final pain score prior to tourniquet deflation. At the end of the procedure, the patient was asked to provide an overall numerical pain score (0–100) for the tourniquet site during the procedure, with zero communicating no pain whatsoever and 100 indicating
the most severe pain. The patient marked this on a 100 mm visual analogue scale (VAS). This data provided subjective measurements of patient discomfort every 2.5 min during the procedure, as well as a global assessment of their pain at the end of the procedure. Blood pressure and heart rate were also recorded at 2.5 min post tourniquet inflation and every subsequent 2.5 min interval throughout the procedure. Blood pressure was subsequently converted to mean arterial pressure (MAP) during data analysis. This data provided two objective measures of patient discomfort during the procedure. The operating surgeon was asked to provide subjective scores using a VAS (scale 0–100) for both the extent of bloodless field (zero being a completely bloodless field and 100 indicating significant bleeding that made completing the procedure impossible). The level of obstruction experienced by surgeon during the procedure, such as impediment of the surgeon’s movement or visual field secondary to the tourniquet was also recorded (zero being no impediment whatsoever and 100 indicating significant obstruction that made completing the procedure impossible). These were recorded as VASs. All 100 patients entering the study completed the study. As all assessment was completed intra-operatively; there was no loss to follow-up.
Statistical analysis Histograms were used to assess for normality of distribution. Age, tourniquet time, pulse and MAP were normally distributed. Changes in pulse, systolic blood pressure, diastolic blood pressure and MAP were also normally distributed. Between-group comparisons of age and tourniquet time were made using Student’s t test. This was also used to make betweengroup comparisons of changes from 2 to 8 min in pulse and MAP. Pearson’s Chi-square test was used to analyse VAS for pain from 2 to 8 min. To examine the changes over the entire recording period, repeated measurements of data were analysed using generalized estimating equations. Chi-squared test was used to compare gender in the groups. Ethical approval was granted for this study by the East of Scotland Ethics Committee.
Results The patient demographics and tourniquet times are displayed in Table 1. There were no statistically significant differences in age, gender or tourniquet time. The mean patient-reported pain score, heart rate and MAP were charted over time (Figure 1, Table 2). There was no statistically significant difference in the
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
963
Cousins et al. Table 1. Inter-group patient demographics (age and gender) and mean procedural tourniquet time. Tourniquet position:
Arm
Forearm
Statistical significance (p value)
Mean age (years) Age range (years) Gender (M:F) Mean tourniquet time (minutes) Tourniquet time range (minutes)
53 32–82 16:34 8.2 2–12
54 30–80 13:37 8.9 4–13
0.641 – 0.509 0.740 –
45 40
Mean pain score (0-100)
35 30 25
forearm arm
20 15 10 5 0
2
4
Time (Mins)
6
8
Figure 1. Mean patient numerical pain score at each 2.5 min interval post tourniquet inflation.
change of heart rate or MAP throughout the procedure between the groups for any of these parameters (Table 2). The median global numerical patient pain score taken at the end of the procedure showed no statistical difference between the two groups (arm = 30; forearm = 23; p = 0.959). The median VAS values recorded by the operating surgeon demonstrated that there was no significant difference in the extent to which a bloodless field was achieved (arm = 10, forearm = 10; p = 0.918; Figure 2). However, in one case in the upper arm group the tourniquet was deflated at 3 min due to uncontrolled bleeding. It was thought that the tourniquet might be contributing to a venous tourniquet effect. The procedure was completed without tourniquet. There was a significant difference in the median VAS values recorded by the operating surgeon for obstruction caused by the tourniquet; the forearm tourniquet caused significantly more obstruction as compared with the upper arm tourniquet (upper arm
= 2; forearm = 10; p = 0.001; Figure 3). The number of arm and forearm cases performed by each surgeon was approximately the same.
Discussion This prospective, randomized and statistically powered study failed to show a statistically significant difference in the level of tourniquet-related pain experienced by patients undergoing CTD using an arm or forearm tourniquet. These results would support previous research from Yousif et al. (1993), Odinsson and Finsen (2002) and Edwards et al. (2000), which also assert that there was no significant relationship between tourniquet position and tourniquet-related patient discomfort. The trial by Yousif et al. (1993) investigated tolerance to arm and forearm tourniquet through randomization of 40 subjects to either group. In addition, they reported on the experience of 18 patients who underwent a
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
964
The Journal of Hand Surgery (Eur) 40(9)
Table 2. Mean change in patient heart rate and mean arterial pressure over course of procedure. Mean change in pain parameter over course of procedure
Tourniquet position: Arm
Forearm
Statistical significance (p value)
Heart rate (bpm) Mean arterial pressure (MAP) (mmHg);
−0.2 (SE 1.4) −0.4 (SE 1.6)
−3.1 (SE 1.3) −1.7 (SE 1.7)
0.128 0.587
30
25
Frequency
20
Forearm Arm
15
10
5
0 0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100
Extent of Bloodless Field (0-100) Figure 2. Histogram of surgeon-reported extent of bloodless field (0–100; 0 = minimum blood; 100 = maximum blood).
45 40 35
Frequency
30
Forearm Arm
25 20 15 10 5 0 0-9
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99
100
Extent of Surgeon Obstruction (0-100) Figure 3. Histogram of surgeon-reported obstruction of surgical field (0–100; 0 = minimum obstruction; 100 = maximum obstruction).
Downloaded from jhs.sagepub.com at UNIV CALIFORNIA SAN DIEGO on November 12, 2015
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Cousins et al. clinical procedure with forearm tourniquet. The article by Odinsson and Finsen (2002) specifically looked at carpal tunnel syndrome and similarly found no difference. However, this article was underpowered and had a wide range of tourniquet time from 6–37 min. Edwards et al. (2000) conducted a prospective trial comparing upper arm and forearm tourniquet for hand surgery under local anaesthetic and suggested no difference in patient experience. Their trial was not randomized and did assess surgeon preference. However, it was adequately powered with 100 patients in each group. A retrospective study (Glynn et al. 2005) of 74 patients that had undergone CTD suggested that forearm tourniquet was well tolerated, but no direct comparison was made with arm tourniquet. A non-clinical trial by Hutchison and McClinton (1993) on 20 volunteers found that forearm tourniquet was tolerated for an average of 45% longer and no participant tolerated an arm tourniquet longer than a forearm tourniquet. This finding was supported by a randomized trial of 24 volunteers (Maury and Roy, 2002) in which forearm tourniquet was tolerated on average 7 min longer than arm tourniquet. This would suggest that a key factor in tourniquet tolerance is duration. The previous studies that have demonstrated a significant difference have done so with average tourniquet times greater than 20 min, which is much longer than the tourniquet times in this series (Table 1). Ogufere et al. (1995) suggested that tourniquet pain is more due to individual idiosyncrasies rather than tourniquet duration if the inflation time was 20 mins or less. The pain scores (which were clearly defined as pain relating to the tourniquet) varied so little in our study that we could not determine any correlating factors, including heart rate and blood pressure. This is contrary to Hutchison and McClinton (1993) who found that blood pressure correlated with pain. Our results also confirm that there is no difference in the extent of bleeding in the surgical field achieved by a tourniquet set at 250 mmHg placed on the forearm as compared with the arm, as measured by a subjective VAS score given by the operating surgeon. Our study did however produce a statistically significant difference in the level of obstruction experienced by the operating surgeon in relation to the position of the tourniquet. This must be understood on the basis that no inter-surgeon variability analysis was performed (as it was felt the operating surgeon would have no bearing on the primary aim of determining levels of pain from the tourniquet. The VAS score relating to obstruction was significantly higher (worse) in the forearm group as compared with the arm group (median arm = 2; median forearm = 10; p = 0.001; Figure 3). As previously discussed, this did
not, however, result in a significant difference in tourniquet time between the two groups (Table 1). In summary, this randomized trial of arm versus forearm tourniquet positioning in CTD has shown no statistically significant difference in subjective (numerical rating scale) and objective (heart rate, MAP) measures of patient discomfort. It remains reasonable for surgeons to select tourniquet position based upon their individual preference. Acknowledgements Linda Cochrane, Statistician University of Dundee.
Conflict of interests None declared.
Ethical approval East of Scotland Research Ethics Service (EoSRES) Research Ethics Committee 2. Approval for study granted 6 February 2012. REC reference 11/ES/0047.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors
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