Eur Arch Otorhinolaryngol DOI 10.1007/s00405-014-3296-8
HEAD AND NECK
Optical magnification devices in tonsillectomy: a prospective randomised clinical study F. Schro¨tzlmair • L. Geerke • U. Kisser C. Reichel • S. Vo¨gele • K. Stelter
•
Received: 2 June 2014 / Accepted: 17 September 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Tonsillectomy is one of the most common surgical procedure in otorhinolaryngology. A plethora of approaches has been undertaken so far to limit postoperative pain, one of the major problems patients are concerned with. Thermal damages of the surrounding tissue caused by coagulation during surgery are discussed to correlate with postoperative pain. Therefore, we studied whether the use of magnification devices reduced coagulation procedures and consequently limited post-operative pain. Following an intraindividual design, we performed tonsillectomy on one side using a microscope or magnifying glasses whereas the opposite side was operated with unsupported vision. As verified by a visual analogue scale, our study shows that neither the use of a microscope, nor the use of magnifying glasses leads to less post-operative pain. Other parameters like post-operative bleeding, duration of surgery, and total applied energy by bipolar coagulation were also comparable in the different treatment groups. Taken together, magnification-supported tonsillectomy does not seem to be appropriate for limiting complications of tonsillectomy, especially not for reducing post-operative pain. Keywords Tonsillectomy Magnification devices Microscope Magnifying glasses Post-operative pain
F. Schro¨tzlmair (&) L. Geerke U. Kisser C. Reichel S. Vo¨gele K. Stelter Klinik und Poliklinik fu¨r Hals-, Nasen- und Ohrenheilkunde, Klinikum der Ludwig-Maximilians-Universita¨t Mu¨nchen, Marchioninistraße 15, 81377 Munich, Germany e-mail: [email protected] K. Stelter e-mail: [email protected]
Introduction Tonsillectomy is still one of the most common surgical procedure in otorhinolaryngology [1]. However, over the last decades, its incidence has constantly been decreasing due to tighter indication as well as the development of alternative surgical procedures like tonsillotomy [2]. This trend mainly relies on the risks and complications which are associated with tonsillectomy. The incidence of possibly life-threatening post-operative bleeding varies between 0 and 20 % of the patients [3]. The other major problem, post-operative pain, affects almost all patients and makes sufficient analgesia necessary. Primarily, non-steroidal anti-inflammatory drugs (NSAID) like coxibes, diclofenac, ibuprofen, ketoprofen and paracetamol, but also several opioids like codeine, tramadol and piritramid are used in peroral or intravenous regimes [4–7]. Furthermore, intraoperative instillation of local anaesthetics seems to reduce post-operative pain [8]. It is also discussed that extensive coagulation procedures during surgery should be avoided to limit post-operative pain [9–11]. To address the problems associated with tonsillectomy, a plethora of surgical techniques has been developed in the last 25 years. The classical ‘‘cold’’ dissection with punctual bipolar coagulation has been joined by ‘‘hot’’ dissecting techniques like diathermy and coblation settings. However, none of these techniques has shown any superiority to the cold steel dissection, especially when comparing the overall rate of post-operative haemorrhage [12, 13]. Also the use of magnifying devices like microscopes or magnifying glasses is still in the focus of clinical investigation as it is hypothesized that precise vision of vessels during surgery allows precise coagulation and therefore reduces post-operative bleeding. Furthermore, precise coagulation should reduce post-operative pain, too [10]. However,
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almost none of the published studies about the use of magnifying devices documented a reduction of tonsillectomy-associated complications [9, 11, 14–17]. This was due to relatively small numbers of patients or the lack of direct comparability between the different treatment groups. In the present study, we aimed to avoid this deficiency by following an intraindividual design. In a total number of 48 patients, we performed tonsillectomy on one side using a microscope or magnifying glasses whereas the opposite side was operated with unsupported vision. After surgery, we asked the patients about post-operative pain. Furthermore, we documented mean cumulative bipolar coagulation, post-operative bleeding, and duration of surgery.
Patients, materials and methods Forty eight patients who underwent elective tonsillectomy were initially included in the study. All tonsillectomies were performed because of recurrent tonsillitis. In children, the criteria defined by Paradise et al. [18] were strictly followed. In adults, tonsillectomy was only performed after at least four episodes of acute tonsillitis during 1 year. Only episodes of a purulent infection of the tonsils which were treated by antibiotics were classified as tonsillitis. All tonsillectomies were performed under general anaesthesia by cold dissection with punctual coagulation using a bipolar forceps when necessary. No patient received
Fig. 1 Tree diagram of the randomised treatment groups
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surgical treatment only because of his participation in the study. Every patient signed informed consent which could be revoked at each time without justification. Criteria for exclusion from the study were: age younger than 6 years, mental disorders, unilateral tonsillectomy, abscess or tumour of the tonsils, pregnancy, anamnestic regular taking of analgetics or anticoagulants, combination with other surgical procedures (except adenotomy and tympanostomy with or without positioning of a ventilation tube). All surgeries were done by four surgeons at the ENT department of the University of Munich in the time span from 07/13/2011 to 08/24/2012. The surgeons had a comparable level of experience in tonsillectomy as all four were at the beginning of their surgical training. Forty eight patients were randomized into three treatment groups with regard to the used technique. Tonsillectomy was either performed with unsupported vision, using magnifying glasses (SuperVu Galilean, magnification 2.5, Rudolf Riester GmbH, Jungingen, Deutschland), or using a microscope (focus 30 cm, magnification 1.6, Carl Zeiss AG, Jena, Deutschland). To avoid interference with the surgeon’s handedness, the 16 patients in each group were further randomized into two groups so that half of the surgical techniques were performed either on the patient’s right or on his left side (Fig. 1). Duration of surgery and total applied energy by bipolar coagulation were documented separately for each side. According to Cardozo et al. [10], the power of the bipolar forceps was recorded in Watt and its use was timed in seconds. Multiplication of
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power and time led to total applied energy in Joule. Like all tonsillectomy patients in our department, the 48 patients were hospitalized for 6 post-operative days. They were asked four times a day (just after awaking, during breakfast, during dinner and before falling asleep) about the pain they were suffering from separately on each side. For graduation of the pain, a visual analogue scale was used (0 means ‘‘no pain’’, 10 means ‘‘maximum of imaginable pain’’). Children used a smiley scale with each smiley being convertible into 0–10 pain points. Mean post-operative pain was calculated separately for conditions at rest and under stress by summarizing the pain points at just after awaking and before falling asleep on the one side and during breakfast and during dinner on the other side. Furthermore, we documented the incidence of post-operative bleeding. Post-operative analgesia followed the standard in our hospital [8]. Patients received ibuprofen 400 mg four times a day per os under gastric protection with 20 mg pantoprazole. If necessary, patients further received 500 mg metamizole peroral or 15 mg piritramid in a short infusion. In children, the individual dose was calculated based on the patient’s body weight. Forty five of the originally 48 randomized patients were finally included in the study because one patient exercised his right to revoke his consent and further two patients inaccurately kept their pain journal (Fig. 1). All data were collected in an excel matrix and analysed using IBM SPSS Statistics 21. To test for significant differences between the surgical methods with regard to post-operative pain, Student’s t test for paired samples was applied; a \ 0.05 was considered significant. To compare duration of surgery and total applied energy by bipolar coagulation, Wilcoxon test
was used. The study design was in compliance with the declaration of Helsinki and the CONSORT statement 2010 and was approved by the ethics committee of the medical faculty of the University of Munich.
Results Use of magnification devices did not reduce postoperative pain Post-operative pain was graduated using a visual analogue scale (0 means ‘‘no pain’’, 10 means ‘‘worst imaginable pain’’) separately for conditions at rest and under stress. As shown for conditions at rest in Figs. 2, 3 and 4, patients rated the pain around 4 of 10 pain points. This rating was similar in all three treatment groups. At most time points, patients felt more pain in the morning than in the evening. Furthermore, post-operative pain started to decrease beginning with day 4 after the surgery. When comparing pain after tonsillectomy with unsupported vision and after surgery with use of magnification devices (groups 1 and 2), no significant differences could be observed although there was a non-significant tendency towards more pain in cases of tonsillectomy with magnifying glasses. The comparison of post-operative pain after tonsillectomy with magnifying glasses or the microscope (group 3) neither revealed any significant differences. In all three treatments groups, analogue results were obtained when comparing pain during the first six post-operative days in situations of mechanical stress in the operated region, e.g. when the patient was eating (data not shown).
Fig. 2 Post-operative pain at rest during the first 6 days after tonsillectomy in treatment group 1 (tonsillectomy using magnifying glasses on the one side vs. tonsillectomy with unsupported vision on the pain in the opposite side; morning; pain in the evening; VAS visual analogue scale; SD standard deviation of the mean): Student’s t test documented no significant difference between the treatment groups (p = 0.08)
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Eur Arch Otorhinolaryngol Fig. 3 Post-operative pain at rest during the first 6 days after tonsillectomy in treatment group 2 (tonsillectomy using a microscope on the one side vs. tonsillectomy with unsupported vision on the opposite side; pain in the morning; pain in the evening; VAS visual analogue scale; SD standard deviation of the mean): Student’s t test documented no significant difference between the treatment groups (p = 0.41)
Fig. 4 Post-operative pain at rest during the first 6 days after tonsillectomy in treatment group 3 (tonsillectomy using magnifying glasses on the one side vs. tonsillectomy using a microscope on the opposite pain in the morning; side; pain in the evening; VAS visual analogue scale; SD standard deviation of the mean): Student’s t test documented no significant difference between the treatment groups (p = 0.93)
Use of magnification devices did not lead to less overall bipolar coagulation We calculated total applied energy due to bipolar coagulation by multiplying the power of the bipolar forceps with the duration of coagulation procedures. The average quantity of energy per tonsillectomy oscillated around 1 kJ (range: 780–1170 J). Neither use of magnifying glasses, nor use of a microscope led to less coagulation during tonsillectomy compared to the surgery with unsupported vision (Fig. 5, groups 1 and 2). Also the comparison
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between tonsillectomies under magnifying glasses and surgeries with support of a microscope did not show any significant differences with regard to bipolar coagulation (Fig. 5, group 3). Use of magnification devices did not accelerate surgery We timed duration of surgery using a stop watch. On average, surgeries took 7.5–10 min (range: 3–26 min) for each side. No significant differences could be observed between the three treatment groups (Fig. 6).
Eur Arch Otorhinolaryngol Fig. 5 Bipolar coagulation in Joule [J] during tonsillectomy (SD standard deviation of the mean; boxes indicate maximum to minimum): Wilcoxon test documented no significant difference between the treatment groups (p = 0.57)
Fig. 6 Duration of tonsillectomy in minutes [min] (SD standard deviation of the mean; boxes indicate maximum to minimum): Wilcoxon test documented no significant difference between the treatment groups (p = 0.07)
Use of magnification devices did not affect post-operative haemorrhage 42 of the 45 patients did not experience any post-operative bleeding. One patient had to be taken to the operation
theatre a second time because of severe bleeding from both sides. This patient had been operated with unsupported vision on the left side and with support of a microscope on the right side. Five patients had episodes of minor postoperative bleeding which did not make any specific therapy
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necessary. Due to the small number of patients experiencing post-operative haemorrhage, statistical analyses were not possible.
Discussion The main outcome measure of the current study was to test whether the use of magnification devices in tonsillectomy reduced post-operative pain. Previous studies suggested a benefit of microscope-assisted tonsillectomy [9, 11]. However, in these studies, it was only possible to document overall post-operative pain due to their interindividual setup. Therefore, we chose an intraindividual design and performed the operation differently on the right and left side with or without using magnifying glasses or a microscope. This design allows the direct comparison of post-operative pain as a function of different surgical methods without inference with interindividual differences in pain perception, analgesia and operating surgeons. The prerequisite of such design is the possibility that patients are able to differentiate the extent of pain between the left and the right side. The capability to do so has been documented in earlier studies [8, 19]. In the present study, patients were asked to protocol pain at rest or under stress using a visual analogue scale with a maximum of 10 points representing worst imaginable pain. As known from previous studies [8, 19], mean post-operative pain oscillated around 4 points (Figs. 2, 3, 4). In the morning, pain was generally more pronounced because this time-point means a relatively long period after the last consumption of analgetics (Figs. 2, 3, 4). When comparing post-operative pain after tonsillectomy with unsupported vision and after surgery using magnification devices, at almost all time points patients did not suffer less pain when magnification devices had been used, regardless whether they were at rest (Figs. 2, 3, 4) or under stress (data not shown). It has been elucidated in vitro that use of bipolar electrosurgical currents for haemostasis during tonsillectomy leads to damages of the surrounding tissue up to a depth of several millimetres [20]. This tissue effect may be the reason for the dose–response relationship between diathermy energy and post-operative pain [10]. As use of magnification devices should allow more precise vision of vessels during preparation of the tonsils, we hypothesized that magnification-supported tonsillectomy required less coagulation procedures, thereby leading to less post-operative pain. However, we could not document a statistical significant difference in mean cumulative diathermy application between the three treatment groups (Fig. 5). On the one hand, this provides a possible explanation for the lack of benefit of magnification devices with regard to postoperative pain. On the other hand, this result raises the
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question why the assumable advantage of better vision during tonsillectomy was not reflected in less morbidity. A possible explanation is that unexperienced surgeons are not familiar with the use magnification devices. Although microscopes and magnifying glasses magnify the region which is in focus, the overall operation field is restricted. Furthermore, the severity of bleedings from small vessels might be over-estimated provoking more coagulation procedures than necessary. The requirements which are associated with the use of magnification devices may also explain why the mean duration of surgery was not reduced compared to the tonsillectomy with unsupported vision (Fig. 6). This finding is in line with previous publications [11, 14–16]. However, training on magnifying devices may overcome these disadvantages. Another major complication of tonsillectomy is postoperative bleeding [3]. Therefore, we analysed whether the use of magnification devices reduced the rate of postoperative haemorrhage. Due to the relatively low number of patients and consequently the low number of bleeding complications, a statistical comparison between the treatment groups with regard to this item was not possible. In most of the earlier studies, a significant reduction of postoperative bleeding due to use of magnification devices could neither be documented, mainly because of the same statistical limitation [9, 10, 13, 14, 16]. Thus, larger series of tonsillectomies must be performed to address this question. Taken together, the present study suggests that patients do not profit from the use of magnification devices in tonsillectomy with regard to post-operative pain as the main outcome parameter. Acknowledgments We thank Rudolf Riester GmbH, Jungingen, Germany, for providing us with magnifying glasses. Conflict of interest The authors declare that they have no conflicts of interest.
References 1. Erickson BK, Larson DR, Sauver JLSt, Meverden RA, Orvidas LJ (2009) Changes in incidence and indications of tonsillectomy and adenotonsillectomy, 1970–2005. Otolaryngol Head Neck Surg 140:894–901 2. Acevedo JL, Shah RK, Brietzke SE (2012) Systematic review of complications of tonsillotomy versus tonsillectomy. Otolaryngol Head Neck Surg 146:871–879 3. Walner DL, Karas A (2013) Standardization of reporting posttonsillectomy bleeding. Ann Otol Rhinol Laryngol 122:277–282 4. Bean-Lijewski JD, Kruitbosch SH, Hutchinson L, Browne B (2007) Post-tonsillectomy pain management in children: can we do better? Otolaryngol Head Neck Surg 137:545–551 5. Hamunen K, Kontinen V (2005) Systematic review on analgesics given for pain following tonsillectomy in children. Pain 117: 40–50
Eur Arch Otorhinolaryngol 6. Kocum AI, Sener M, Caliskan E, Bozdogan N, Micozkadioglu D, Yilmaz I, Aribogan A (2013) Intravenous paracetamol and dipyrone for postoperative analgesia after day-case tonsillectomy in children: a prospective, randomized, double-blind, placebo controlled study. Braz J Otorhinolaryngol 79:89–94 7. Sutters KA, Miaskowski C, Holdrige-Zeuner D, Waite S, Paul SM, Savedra MC, Lanier B, Mahoney K (2010) A randomized clinical trial of the efficacy of scheduled dosing of acetaminophen and hydrocodone for the management of postoperative pain in children after tonsillectomy. Clin J Pain 26:95–103 8. Stelter K, Hiller J, Hempel JM, Berghaus A, Hagedorn H, Andratschke M, Canis M (2010) Comparison of two different local anaesthetic infiltrations for postoperative pain relief in tonsillectomy: a prospective, randomised, double blind, clinical trial. Eur Arch Otorhinolaryngol 267:1129–1134 9. Andrea M (1993) Microsurgical bipolar cautery tonsillectomy. Laryngoscope 103:1177–1178 10. Cardozo AAJ, Hallikeri C, Lawrence H, Sankar V, Hargreaves S (2007) Teenage and adult tonsillectomy: dose-response relationship between diathermy energy used and morbidity. Clin Otolaryngol 32:366–371 11. Kujawski O, Dulguerov P, Gysin C, Lehmann W (1997) Microscopic tonsillectomy: a double-blind randomized trial. Otolaryngol Head Neck Surg 117:641–647 12. Lowe D, von der Meulen J (2004) Tonsillectomy technique as a risk factor for postoperative haemorrhage. Lancet 364:697–702 13. Blanchford H, Lowe D (2013) Cold versus hot tonsillectomy: state of the art and recommendations. ORL J Otrohinolaryngol Relat Spec 75:136–141
14. De Carpentier J, Timms M (1994) Preliminary experiences with microscopic tonsillectomy. Clin Otolaryngol Allied Sci 19:352–354 15. Lassaletta L, Martin G, Bolan˜os C, Alvarez-Vicent JJ (1997) Pediatric tonsillectomy: post-operative morbidity comparing microsurgical bipolar dissection versus cold sharp dissection. Int J Pediatr Otorhinolaryngol 41:307–317 16. Pizzuto MP, Brodsky L, Duffy L, Gendler J, Nauenberg E (2000) A comparison of microbipolar cautery dissection to hot knife and cold knife cautery tonsillectomy. Int J Pediatr Otorhinolaryngol 52:239–246 17. Ulualp SO (2012) Rate of post-tonsillectomy hemorrhage after elective bipolar microcauterization of nonbleeding vessels. Eur Arch Otorhinolaryngol 269:1269–1275 18. Paradise JL, Bluestone CD, Bachman RZ, Colborn DK, Bernard BS, Taylor FH, Rogers KD, Schwarzbach RH, Stool SE, Friday GA, Smith IH, Saez CA (1984) Efficacy of tonsillectomy for recurrent throat infection in severely affected children—results of parallel randomized and nonrandomized clinical trials. N Engl J Med 310:674–683 19. Stelter K, Hempel JM, Berghaus A, Andratschke M, Lu¨bbers CW, Hagedorn W (2009) Application methods of local anaesthetic infiltrations for postoperative pain relief in tonsillectomy: a prospective, randomised, double-blind, clinical trial. Eur Arch Otorhinolaryngol 266:1615–1620 20. Habermann W, Mu¨ller W (2013) Tissue penetration of bipolar electrosurgical currents: Joule overheating beyond the surface layer. Head Neck 35:535–540
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HEAD AND NECK
Optical magnification devices in tonsillectomy: a prospective randomised clinical study F. Schro¨tzlmair • L. Geerke • U. Kisser C. Reichel • S. Vo¨gele • K. Stelter
•
Received: 2 June 2014 / Accepted: 17 September 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Tonsillectomy is one of the most common surgical procedure in otorhinolaryngology. A plethora of approaches has been undertaken so far to limit postoperative pain, one of the major problems patients are concerned with. Thermal damages of the surrounding tissue caused by coagulation during surgery are discussed to correlate with postoperative pain. Therefore, we studied whether the use of magnification devices reduced coagulation procedures and consequently limited post-operative pain. Following an intraindividual design, we performed tonsillectomy on one side using a microscope or magnifying glasses whereas the opposite side was operated with unsupported vision. As verified by a visual analogue scale, our study shows that neither the use of a microscope, nor the use of magnifying glasses leads to less post-operative pain. Other parameters like post-operative bleeding, duration of surgery, and total applied energy by bipolar coagulation were also comparable in the different treatment groups. Taken together, magnification-supported tonsillectomy does not seem to be appropriate for limiting complications of tonsillectomy, especially not for reducing post-operative pain. Keywords Tonsillectomy Magnification devices Microscope Magnifying glasses Post-operative pain
F. Schro¨tzlmair (&) L. Geerke U. Kisser C. Reichel S. Vo¨gele K. Stelter Klinik und Poliklinik fu¨r Hals-, Nasen- und Ohrenheilkunde, Klinikum der Ludwig-Maximilians-Universita¨t Mu¨nchen, Marchioninistraße 15, 81377 Munich, Germany e-mail: [email protected] K. Stelter e-mail: [email protected]
Introduction Tonsillectomy is still one of the most common surgical procedure in otorhinolaryngology [1]. However, over the last decades, its incidence has constantly been decreasing due to tighter indication as well as the development of alternative surgical procedures like tonsillotomy [2]. This trend mainly relies on the risks and complications which are associated with tonsillectomy. The incidence of possibly life-threatening post-operative bleeding varies between 0 and 20 % of the patients [3]. The other major problem, post-operative pain, affects almost all patients and makes sufficient analgesia necessary. Primarily, non-steroidal anti-inflammatory drugs (NSAID) like coxibes, diclofenac, ibuprofen, ketoprofen and paracetamol, but also several opioids like codeine, tramadol and piritramid are used in peroral or intravenous regimes [4–7]. Furthermore, intraoperative instillation of local anaesthetics seems to reduce post-operative pain [8]. It is also discussed that extensive coagulation procedures during surgery should be avoided to limit post-operative pain [9–11]. To address the problems associated with tonsillectomy, a plethora of surgical techniques has been developed in the last 25 years. The classical ‘‘cold’’ dissection with punctual bipolar coagulation has been joined by ‘‘hot’’ dissecting techniques like diathermy and coblation settings. However, none of these techniques has shown any superiority to the cold steel dissection, especially when comparing the overall rate of post-operative haemorrhage [12, 13]. Also the use of magnifying devices like microscopes or magnifying glasses is still in the focus of clinical investigation as it is hypothesized that precise vision of vessels during surgery allows precise coagulation and therefore reduces post-operative bleeding. Furthermore, precise coagulation should reduce post-operative pain, too [10]. However,
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almost none of the published studies about the use of magnifying devices documented a reduction of tonsillectomy-associated complications [9, 11, 14–17]. This was due to relatively small numbers of patients or the lack of direct comparability between the different treatment groups. In the present study, we aimed to avoid this deficiency by following an intraindividual design. In a total number of 48 patients, we performed tonsillectomy on one side using a microscope or magnifying glasses whereas the opposite side was operated with unsupported vision. After surgery, we asked the patients about post-operative pain. Furthermore, we documented mean cumulative bipolar coagulation, post-operative bleeding, and duration of surgery.
Patients, materials and methods Forty eight patients who underwent elective tonsillectomy were initially included in the study. All tonsillectomies were performed because of recurrent tonsillitis. In children, the criteria defined by Paradise et al. [18] were strictly followed. In adults, tonsillectomy was only performed after at least four episodes of acute tonsillitis during 1 year. Only episodes of a purulent infection of the tonsils which were treated by antibiotics were classified as tonsillitis. All tonsillectomies were performed under general anaesthesia by cold dissection with punctual coagulation using a bipolar forceps when necessary. No patient received
Fig. 1 Tree diagram of the randomised treatment groups
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surgical treatment only because of his participation in the study. Every patient signed informed consent which could be revoked at each time without justification. Criteria for exclusion from the study were: age younger than 6 years, mental disorders, unilateral tonsillectomy, abscess or tumour of the tonsils, pregnancy, anamnestic regular taking of analgetics or anticoagulants, combination with other surgical procedures (except adenotomy and tympanostomy with or without positioning of a ventilation tube). All surgeries were done by four surgeons at the ENT department of the University of Munich in the time span from 07/13/2011 to 08/24/2012. The surgeons had a comparable level of experience in tonsillectomy as all four were at the beginning of their surgical training. Forty eight patients were randomized into three treatment groups with regard to the used technique. Tonsillectomy was either performed with unsupported vision, using magnifying glasses (SuperVu Galilean, magnification 2.5, Rudolf Riester GmbH, Jungingen, Deutschland), or using a microscope (focus 30 cm, magnification 1.6, Carl Zeiss AG, Jena, Deutschland). To avoid interference with the surgeon’s handedness, the 16 patients in each group were further randomized into two groups so that half of the surgical techniques were performed either on the patient’s right or on his left side (Fig. 1). Duration of surgery and total applied energy by bipolar coagulation were documented separately for each side. According to Cardozo et al. [10], the power of the bipolar forceps was recorded in Watt and its use was timed in seconds. Multiplication of
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power and time led to total applied energy in Joule. Like all tonsillectomy patients in our department, the 48 patients were hospitalized for 6 post-operative days. They were asked four times a day (just after awaking, during breakfast, during dinner and before falling asleep) about the pain they were suffering from separately on each side. For graduation of the pain, a visual analogue scale was used (0 means ‘‘no pain’’, 10 means ‘‘maximum of imaginable pain’’). Children used a smiley scale with each smiley being convertible into 0–10 pain points. Mean post-operative pain was calculated separately for conditions at rest and under stress by summarizing the pain points at just after awaking and before falling asleep on the one side and during breakfast and during dinner on the other side. Furthermore, we documented the incidence of post-operative bleeding. Post-operative analgesia followed the standard in our hospital [8]. Patients received ibuprofen 400 mg four times a day per os under gastric protection with 20 mg pantoprazole. If necessary, patients further received 500 mg metamizole peroral or 15 mg piritramid in a short infusion. In children, the individual dose was calculated based on the patient’s body weight. Forty five of the originally 48 randomized patients were finally included in the study because one patient exercised his right to revoke his consent and further two patients inaccurately kept their pain journal (Fig. 1). All data were collected in an excel matrix and analysed using IBM SPSS Statistics 21. To test for significant differences between the surgical methods with regard to post-operative pain, Student’s t test for paired samples was applied; a \ 0.05 was considered significant. To compare duration of surgery and total applied energy by bipolar coagulation, Wilcoxon test
was used. The study design was in compliance with the declaration of Helsinki and the CONSORT statement 2010 and was approved by the ethics committee of the medical faculty of the University of Munich.
Results Use of magnification devices did not reduce postoperative pain Post-operative pain was graduated using a visual analogue scale (0 means ‘‘no pain’’, 10 means ‘‘worst imaginable pain’’) separately for conditions at rest and under stress. As shown for conditions at rest in Figs. 2, 3 and 4, patients rated the pain around 4 of 10 pain points. This rating was similar in all three treatment groups. At most time points, patients felt more pain in the morning than in the evening. Furthermore, post-operative pain started to decrease beginning with day 4 after the surgery. When comparing pain after tonsillectomy with unsupported vision and after surgery with use of magnification devices (groups 1 and 2), no significant differences could be observed although there was a non-significant tendency towards more pain in cases of tonsillectomy with magnifying glasses. The comparison of post-operative pain after tonsillectomy with magnifying glasses or the microscope (group 3) neither revealed any significant differences. In all three treatments groups, analogue results were obtained when comparing pain during the first six post-operative days in situations of mechanical stress in the operated region, e.g. when the patient was eating (data not shown).
Fig. 2 Post-operative pain at rest during the first 6 days after tonsillectomy in treatment group 1 (tonsillectomy using magnifying glasses on the one side vs. tonsillectomy with unsupported vision on the pain in the opposite side; morning; pain in the evening; VAS visual analogue scale; SD standard deviation of the mean): Student’s t test documented no significant difference between the treatment groups (p = 0.08)
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Fig. 4 Post-operative pain at rest during the first 6 days after tonsillectomy in treatment group 3 (tonsillectomy using magnifying glasses on the one side vs. tonsillectomy using a microscope on the opposite pain in the morning; side; pain in the evening; VAS visual analogue scale; SD standard deviation of the mean): Student’s t test documented no significant difference between the treatment groups (p = 0.93)
Use of magnification devices did not lead to less overall bipolar coagulation We calculated total applied energy due to bipolar coagulation by multiplying the power of the bipolar forceps with the duration of coagulation procedures. The average quantity of energy per tonsillectomy oscillated around 1 kJ (range: 780–1170 J). Neither use of magnifying glasses, nor use of a microscope led to less coagulation during tonsillectomy compared to the surgery with unsupported vision (Fig. 5, groups 1 and 2). Also the comparison
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between tonsillectomies under magnifying glasses and surgeries with support of a microscope did not show any significant differences with regard to bipolar coagulation (Fig. 5, group 3). Use of magnification devices did not accelerate surgery We timed duration of surgery using a stop watch. On average, surgeries took 7.5–10 min (range: 3–26 min) for each side. No significant differences could be observed between the three treatment groups (Fig. 6).
Eur Arch Otorhinolaryngol Fig. 5 Bipolar coagulation in Joule [J] during tonsillectomy (SD standard deviation of the mean; boxes indicate maximum to minimum): Wilcoxon test documented no significant difference between the treatment groups (p = 0.57)
Fig. 6 Duration of tonsillectomy in minutes [min] (SD standard deviation of the mean; boxes indicate maximum to minimum): Wilcoxon test documented no significant difference between the treatment groups (p = 0.07)
Use of magnification devices did not affect post-operative haemorrhage 42 of the 45 patients did not experience any post-operative bleeding. One patient had to be taken to the operation
theatre a second time because of severe bleeding from both sides. This patient had been operated with unsupported vision on the left side and with support of a microscope on the right side. Five patients had episodes of minor postoperative bleeding which did not make any specific therapy
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necessary. Due to the small number of patients experiencing post-operative haemorrhage, statistical analyses were not possible.
Discussion The main outcome measure of the current study was to test whether the use of magnification devices in tonsillectomy reduced post-operative pain. Previous studies suggested a benefit of microscope-assisted tonsillectomy [9, 11]. However, in these studies, it was only possible to document overall post-operative pain due to their interindividual setup. Therefore, we chose an intraindividual design and performed the operation differently on the right and left side with or without using magnifying glasses or a microscope. This design allows the direct comparison of post-operative pain as a function of different surgical methods without inference with interindividual differences in pain perception, analgesia and operating surgeons. The prerequisite of such design is the possibility that patients are able to differentiate the extent of pain between the left and the right side. The capability to do so has been documented in earlier studies [8, 19]. In the present study, patients were asked to protocol pain at rest or under stress using a visual analogue scale with a maximum of 10 points representing worst imaginable pain. As known from previous studies [8, 19], mean post-operative pain oscillated around 4 points (Figs. 2, 3, 4). In the morning, pain was generally more pronounced because this time-point means a relatively long period after the last consumption of analgetics (Figs. 2, 3, 4). When comparing post-operative pain after tonsillectomy with unsupported vision and after surgery using magnification devices, at almost all time points patients did not suffer less pain when magnification devices had been used, regardless whether they were at rest (Figs. 2, 3, 4) or under stress (data not shown). It has been elucidated in vitro that use of bipolar electrosurgical currents for haemostasis during tonsillectomy leads to damages of the surrounding tissue up to a depth of several millimetres [20]. This tissue effect may be the reason for the dose–response relationship between diathermy energy and post-operative pain [10]. As use of magnification devices should allow more precise vision of vessels during preparation of the tonsils, we hypothesized that magnification-supported tonsillectomy required less coagulation procedures, thereby leading to less post-operative pain. However, we could not document a statistical significant difference in mean cumulative diathermy application between the three treatment groups (Fig. 5). On the one hand, this provides a possible explanation for the lack of benefit of magnification devices with regard to postoperative pain. On the other hand, this result raises the
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question why the assumable advantage of better vision during tonsillectomy was not reflected in less morbidity. A possible explanation is that unexperienced surgeons are not familiar with the use magnification devices. Although microscopes and magnifying glasses magnify the region which is in focus, the overall operation field is restricted. Furthermore, the severity of bleedings from small vessels might be over-estimated provoking more coagulation procedures than necessary. The requirements which are associated with the use of magnification devices may also explain why the mean duration of surgery was not reduced compared to the tonsillectomy with unsupported vision (Fig. 6). This finding is in line with previous publications [11, 14–16]. However, training on magnifying devices may overcome these disadvantages. Another major complication of tonsillectomy is postoperative bleeding [3]. Therefore, we analysed whether the use of magnification devices reduced the rate of postoperative haemorrhage. Due to the relatively low number of patients and consequently the low number of bleeding complications, a statistical comparison between the treatment groups with regard to this item was not possible. In most of the earlier studies, a significant reduction of postoperative bleeding due to use of magnification devices could neither be documented, mainly because of the same statistical limitation [9, 10, 13, 14, 16]. Thus, larger series of tonsillectomies must be performed to address this question. Taken together, the present study suggests that patients do not profit from the use of magnification devices in tonsillectomy with regard to post-operative pain as the main outcome parameter. Acknowledgments We thank Rudolf Riester GmbH, Jungingen, Germany, for providing us with magnifying glasses. Conflict of interest The authors declare that they have no conflicts of interest.
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