K Stelter1*, SH Kim2, L Geerke3, U Kisser3, C Reichel3, S Vögele3 and F Schrötzlmair3
1HNO Zentrum Mangfall-Inn, Rosenheim, Germany
2Poliklinik für Phoniatrie der RWTH Aachen, Germany
Received: 29 May, 2017; Accepted: 12 July, 2017; Published: 14 July, 2017
Klaus Stelter, MD, HNO Zentrum Mangfall-Inn, Rosenheim, Germany, Tel: 08031 / 12425; Fax: 08031/14513; E-mail:
Stelter K, Kim SH, Geerke L, Kisser U, Reichel C, et al. (2017) Effort to engage Magnification Devices in Educational Tonsillectomy - A prospective clinical trial. Arch Otolaryngol Rhinol 3(3): 064-070. DOI: 10.17352/2455-1759.000049
© 2017 Stelter K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Tonsillectomy; Magnification devices; Microscope; Magnifying glasses; Ergonomics; Heart rate; Heart rate variability, Effort to engage; Situation awareness
Introduction: Most educational hospitals teach the tonsil surgery just with head lights and without any magnification device. This prospective clinical trial focuses on the additional workload when using a microscope or magnifying glasses for tonsillectomy.
Material and methods: four surgeons in training with no experience in tonsil surgery operated on 48 patients who underwent elective extracapsular tonsillectomy. Surgery was either performed on one patient´s side with the naked eyes plus headlamp and on the other side with magnifying glasses or a microscope. The surgeons were connected to a biofeedback device in order to monitor the breathing frequency, the heart rate variability and the masseter tone. After every operation surgeons filled out the NasaTLX questionnaire for evaluating the cognitive workload during surgery.
Results: There was a significant difference in the questioning and the heartrate variability when using the microscope compared to the naked eyes and the magnifying glasses. However, there was no statistical difference in mean operation time for all study arms.
Conclusion: Compared to loupes the mental distress is higher when operating a microscope in the first eight times. Despite the many advantages of an OR-microscope, this fact may hinder the usability of such a device in tonsillectomy.
Tonsillectomy is still one of the most common surgical procedures in otorhinolaryngology . 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 . This trend mainly relies on the risks and complications which are associated with tonsillectomy: namely post-operative bleeding and pain. 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 . Furthermore, intraoperative instillation of local anaesthetics and the surgical technique seem to reduce postoperative pain . The classical “cold” dissection with ligatures or punctual bipolar coagulation has been joined in the last few years by “hot” dissecting techniques like radiofrequency, laser, diathermy, ultrasound and coblation settings. However, none of these techniques has shown any superiority to the cold steel dissection, especially when comparing the overall rate of postoperative haemorrhage and pain [5-7]. Andrea M. emphasized 1993 that the use of magnifying devices like microscopes or magnifying glasses allows precise vision and coagulation of vessels during surgery and therefore reduces postoperative bleeding [8,9]. Furthermore, precise coagulation with less collateral damage seems to reduce postoperative pain and intraoperative bleeding, too . Unfortunately in our own study we found no difference in postoperative pain in 48 patients when using magnifying devices for tonsillectomy . To overcome the problem of individual pain sensation, we performed tonsillectomy on one side using a microscope or magnifying glasses whereas the opposite side was operated with the naked eyes, thus following an intraindividual design. After surgery, the patients were asked about postoperative pain specifically on the left against the right side. Although there was no statistical significant difference between the methods concerning pain and hemorrhage, the use of magnifying devices, especially a microscope with camera or spy opens new ways of surgical education and exact preparation in the tonsillar capsule. However, most university clinics and educational hospitals still teach the cold steel tonsillectomy just with head lights and without any magnification device. A possible reason for this could be the relatively high effort to engage any microscope in the OR and the additional workload for the trainee when dealing with another medical device. To quantify the psychological and physiological effort to engage, the ergonomics and the additional workload when using a microscope or magnifying glasses for tonsillectomy in surgical training the following clinical trial was conducted.
Materials and Methods
N=4 surgeons (3 male, 1 female, in average = 27years old with standard deviation (SD) of 1.4years) in training operated on 48 patients who underwent elective tonsillectomy because of recurrent tonsillitis. The inclusion criteria for the surgeons was a comparable level of experience in tonsillectomy: all four were at the beginning of their surgical training and had no experience in tonsil surgery. All tonsillectomies were performed under general anaesthesia by cold dissection with punctual coagulation using a bipolar forceps when necessary. According to the local Ethic Committee approval and the declaration of Helsinki every surgeon and 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 ventilation tubes). All surgeries were done at the ENT department of the University of Munich in the timespan from 07/13/2011 to 08/24/2012.
Every subject (surgeon) had to operate on 12 patients, which means dissecting 24 tonsils with and without magnifying devices. Patients were randomized into three treatment groups according to the used magnifying device. Tonsillectomy was either performed with the naked eyes and headlamp, or using magnifying glasses (SuperVu Galilean, magnification 2.5 with headlamp, Rudolf Riester GmbH, Jungingen, Deutschland), or using a microscope (OPMI 9, focus 30 cm, magnification 1.6, Carl Zeiss AG, Jena, Deutschland). To avoid interference with the surgeon’s handedness, the 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.During the operation and 5 minutes before and afterwards the surgeons were connected to a biofeedback device (NeXus 10, Mindmedia, NL), in order to monitor the breathing frequency, heart frequency (HF), the heart rate variability (HRV) and the masseter tone continuously. Start and end of each tonsillectomy were marked by a manual trigger of the biofeedback device.
In the spectral analysis of the HRV three frequency bands are important:
Very Low Frequency: 0.02-0.06 Hz
Low Frequency: 0.07-0.14 Hz
High Frequency: 0.15-0.40 Hz
A temperature component is included in the low frequency band, the blood pressure component is included in the 0,1 Hz frequency (low frequency band) and the respiratory component is in the high frequency band.
In exhausting mental activity the heart beat becomes more regular to ensure a continuous oxygen supply of the brain. The same procedure can be observed by physical effort. The higher the mental or physical effort of the test person, the lower is the variability of the heartbeat, which means the more regular the heart beats. Thereby, the deviations of the mean interbeat intervals get smaller. This way it can be measured how exhausting the mental workload for an organism is. All three frequencies show a suppression of the HRV by exertion and concentration , but the biggest difference is seen in the low frequency band, especially by the 0,1 Hz component [12,13]. The HRV was monitored during the whole operation and five minutes before and afterwards continuously. This way a calibration with rest situations was given. The spectral analysis of the interbeat intervalls have been implemented with the program BIOTRACE+ (developed by MindMedia in NL). With this spectral analysis it is possible to make a differentiation of the three frequency bands listed above and to quantificate them. BIOTRACE uses the siscrete fourier analysis to split the time series into spectra.
As an additional indicator of physical and mental effort the masseter tonus was measured, too . In situations of high tension a significantly higher masseter tone is measurable through the unconscious contraction of the muscles by biting on the jaws.
Figure 1 – The three different study groups with the monitored surgeons.