Harmonic scalpel tonsillectomy versus monopolar diathermy tonsillectomy: a prospective study.

Abstract

For tonsillectomy, the ultrasonic harmonic scalpel has been purported to cause less tissue injury and postoperative morbidity while providing adequate levels of hemostasis. We undertook a prospective study to compare outcomes in 162 patients who had undergone harmonic scalpel tonsillectomy and 40 patients who had undergone monopolar diathermy tonsillectomy over a 33-month period. We found that patients in the harmonic scalpel group experienced significantly less intraoperative bleeding (5.0 vs. 16.5 ml; p < 0.0001). There was no clinically significant difference between the groups with respect to (1) the amount of operating time, (2) the incidence of postoperative nausea and vomiting, dysphonia, and primary or secondary bleeding, and (3) the amount of time patients needed to resume normal diet and activities.

Introduction

Tonsillar surgery, which was referred to by Celsus as far back as the 1st century AD, (1) has been undertaken with a range of surgical instruments and techniques. The most common tonsillectomy techniques employed at our hospitals are electrocautery with monopolar or bipolar diathermy, cold dissection, plasma-mediated radiofrequency-based ablation (Coblation), and ultrasonic dissection. Evidence for the advantages of some techniques over others is frequently limited, and the optimum technique and instrumentation for tonsillectomy are still controversial. The vast majority of authors report positive findings for whichever instrument or technique is being studied.

Despite significant refinements in surgical technique, instrumentation, and anesthesia delivery, postoperative complications and a relatively slow return to normal diet and activities remain significant challenges for surgeons and patients alike. The goals of the development of new techniques should be to reduce the degree of postoperative pain, nausea, and vomiting and the amount of primary (<24 hr) and secondary (>24 hr) bleeding. Another important objective should be to shorten the amount of time needed to resume normal diet and activities. Finally, new techniques should also be easy to learn and perform.

The most common modality used for tonsillectomy in New South Wales, Australia, is electrodissection tonsillectomy with monopolar diathermy. This technique is associated with a shorter operating time and less intraoperative bleeding compared with cold dissection techniques, but there is some evidence that it may cause more postoperative pain and bleeding. (2) We had an interest in investigating an instrument--the ultrasonic harmonic scalpel (Ethicon Endo-Surgery; Cincinnati)--that would allow us to (1) control intraoperative bleeding to the extent achieved with electrocautery and (2) reduce the degree of tissue damage and postoperative morbidity.

The harmonic scalpel was introduced in 1992. It is a handheld device that is equipped with an ultrasonically activated blade tip that vibrates at 55,500 cycles per second. The blade simultaneously cuts tissue and coagulates it by breaking hydrogen bonds and denaturing protein to form a sticky coagulum. (3) With the harmonic scalpel, coagulation occurs at a temperature between 50 and 100[degrees]C; with electrocautery, coagulation occurs between 150 and 400[degrees]C. Thus, the harmonic scalpel should limit thermal damage and thereby reduce postoperative morbidity. (3,4) Moreover, it should improve visibility in the surgical field because it causes less charring, desiccation, and smoke formation than do electrocautery and laser techniques. (4)

The harmonic scalpel has been used successfully in a variety of surgical procedures--primarily intra-abdominal, intrathoracic, and gynecologic operations. (5-11) It has also been evaluated in a number of animal studies with respect to bleeding, healing, and adhesion formation, but those results have been mixed. (3,12) Its use in tonsillectomy was first described by Ochi et al in 2000. (13) Since then, a number of studies have been published, but only four compared the harmonic scalpel with electrocautery. (14-17) In this article, we present the results of our comparison of the harmonic scalpel and monopolar diathermy.

Patients and methods

This prospective study was designed to analyze outcomes in patients who had undergone tonsillectomy or adenotonsillectomy with either the harmonic scalpel or monopolar diathermy between March 1, 2002, and Nov. 30, 2004. During this period, 202 patients were recruited into the study. Of these, 162 underwent tonsillectomy with the harmonic scalpel and 40 with monopolar diathermy. In the harmonic scalpel group, 46 patients underwent tonsillectomy alone and 116 underwent tonsillectomy with adenoidectomy. The corresponding numbers in the monopolar diathermy group were 18 and 22. Patients' ages ranged from 2 to 65 years; the median age of the harmonic scalpel group was 5.3 years, and the median age of the diathermy group was 14.1 years--a statistically significant difference (p = 0.006). Patients were recruited at the time of their private consultation, and consent was obtained then.

The details of each operation were recorded by the surgeon at the time of surgery. Patients were blinded as to the type of operation. The most common indications for surgery were recurrent tonsillitis, obstructive sleep apnea, or both.

All procedures were performed by one of four consultant surgeons (R.S., M.F., N.B., or W.J.) at one of two private Sydney hospitals (the Mater Hospital or the Sydney Adventist Hospital). All surgeries were performed with general anesthesia. An extracapsular dissection technique was used in both groups. Hemostasis was achieved solely with the instrument under investigation. The length of the operation was calculated from the time the first incision was made until hemostasis was achieved. Intraoperative blood loss was estimated by assuming that a single soaked piece of Raytec gauze would hold 5 ml of blood; the amount of any suctioned blood was also estimated. No postoperative dietary restrictions were placed on patients because there is evidence that maintenance of a normal diet results in a more rapid recovery. [18] All patients were discharged within 24 hours and given 5 days of oral cephalexin (or erythromycin for allergic patients) and a prescription for paracetamol (acetaminophen) with codeine phosphate tablets.

Each patient or primary caregiver was supplied with a 14-day diary in which to score the patient's symptoms and activities by choosing from a graded list. These categories served as the primary outcome variables: (1) the incidence of postoperative nausea and vomiting, dysphonia, and bleeding and (2) the amount of time needed to resume normal diet and activities. The diaries were returned to the primary surgeon at the 2-week follow-up visit. Secondary outcomes of interest were recorded by the surgeons; they included the length of the operation and the amount of intraoperative bleeding.

All analyses were performed with SAS version 8.2 software (SAS; Cary, N.C.). Given the nonparametric distributions of all outcomes, comparisons between methods were made with Wilcoxon rank-sum tests. Results were reported as medians with an interquartile range (IR). (The IR is a measure of statistical dispersion. It represents the distance between the 75th and 25th percentiles. It is a more stable statistic than the total range.) The time required to resume normal activities was analyzed as survival data with log-rank tests; all patients who had not returned to normal by study's end were assigned the maximum time (14 days), and these data were treated as censored data. A two-sided p value of 0.05 was considered to be statistically significant. Because of non-normality, no multivariate analysis was performed.

Results

Operating time. The median operating time in the two groups was the same: 20 minutes.

Intraoperative bleeding. There was a statistically significant difference in the amount of intraoperative blood loss between the two groups. The harmonic scalpel group lost a median of 5.0 ml (IR: 5 to 10) and the diathermy group a median of 16.5 ml (IR: 10 to 27.5) (p < 0.0001).

Nausea and vomiting. Although there was a statistically significant difference in nausea and vomiting scores reported by patients in the two groups on day 9 (p = 0.002) and day 12 (p = 0.038), the median scores of both groups on those days were identical. There was no significant difference in the number of days it took patients in the two groups to report normal scores. On a scale of 1 (severe nausea and vomiting) to 5 (no nausea and vomiting), the median score for all days was 4.9 (IR: 4.7 to 5.0) in the harmonic scalpel group and 4.8 (IR: 4.6 to 5.0) in the monopolar diathermy group (p = 0.04). One patient in the diathermy group was still nauseous at the end of the study, whereas all harmonic scalpel patients reported normal nausea scores by that time (p = 0.041). While some of these differences were statistically significant, they were not likely clinically significant.

Dysphonia. There was no significant difference in dysphonia scores between the two groups.

Postoperative bleeding. One patient in each group experienced a primary hemorrhage. There was no significant difference in the amount of blood loss reported by the two groups on any postoperative day.

Return to normal diet and activities. There was no significant difference in eating scores between the two groups apart from a marginally significant difference on day 4 (p = 0.049); however, the mean scores reported by both groups on day 4 were the same. Patients in the harmonic scalpel group needed an average of 10 days (IR: 8 to 13) to resume eating normally, compared with an average of 11 days (IR: 10 to 13) for the diathermy patients--not a significant difference. All patients reported normal eating scores by the end of the follow-up period.

No significant difference was seen in drinking scores between the two groups on any individual day. Patients in the harmonic scalpel group required a median of 8 days (IR: 5 to 11) to return to normal levels of drinking, and the patients in the diathermy group needed a median of 9 days (IR: 6.5 to 11)--again, not a significant difference. All patients reported normal drinking scores by the end of the follow-up period.

Patients in the harmonic scalpel group reported marginally better activity scores on days 3, 6, and 7 (p < 0.01). They required a median of 10 days (IR: 7 to 12) to return to normal activities, while the diathermy groups required 11 days (IR: 9 to 12)--another nonsignificant difference. All patients in both groups had returned to their usual level of activities by postoperative day 14.

Discussion

New surgical instruments that are purported to benefit both surgeons and patients are being developed and marketed at a rate not previously seen. The findings of early studies of these new instruments are mostly positive. The results of our study suggest that tonsillectomy with the harmonic scalpel may result in less intraoperative blood loss, but this procedure was no different from monopolar diathermy in all other outcomes measured.

Our study found that harmonic scalpel tonsillectomy did not take any longer to complete than did monopolar diathermy tonsillectomy. This finding confirms those of several other authors. (17,19,20) On the other hand, Willging and Wiatrak found that using the harmonic scalpel required significantly more time per tonsil (8 min 42 sec) than did conventional electrocautery (4 min 33 sec). (15) As far as we know, no study has found that use of the harmonic scalpel significantly reduces operating time.

The amount of intraoperative blood that is lost during tonsillectomy depends on a number of factors, including the surgeon's experience, the status of the tonsil, the speed of the surgery, the instrument used for dissection, and the method of achieving hemostasis. The method of recording blood loss is also important, with objective measures being preferred.

Intraoperative blood loss during harmonic scalpel tonsillectomy has been examined in a number of series. In their comparison of the harmonic scalpel and electrocautery, Willging and Wiatrak found no significant difference in the amount of intraoperative blood loss. (15) On the other hand, Collison and Weiner reported significantly less blood loss during harmonic scalpel tonsillectomy (mean: 6.2 ml) than during cold dissection with suction electrocautery for hemostasis (mean: 58.8 ml). (19) Likewise, Kamal et al found that the harmonic scalpel was associated with significantly less intraoperative blood loss (6.2 ml) than was cold steel tonsillectomy with bipolar diathermy for hemostasis (49.4 ml). (20)

In our study, patients in the harmonic scalpel group reported significantly less nausea and vomiting on days 9 and 12, as well as overall. However, the magnitude of the difference was small and is unlikely to be clinically significant. Postoperative dysphonia was not an issue.

No significant difference in postoperative bleeding was seen between our two groups. The validity of this finding is supported by the results of a number of comparisons of harmonic scalpel tonsillectomy with either cold steel or electrocautery techniques. (14,15,17,21) Kamal et al reported no postoperative bleeding at all in 180 patients who had undergone harmonic scalpel tonsillectomy. (20) However, given the low incidence of secondary hemorrhage overall, it is possible that many studies (including ours) might have been insufficiently powered to detect a significant difference if one did exist.

We found no difference in the number of days that passed before patients in our two groups were able to resume a normal diet. Likewise, in a comparison of harmonic scalpel and electrocautery tonsillectomy, Morgenstein et al found no difference in the number of days that had passed until patients in the two groups could tolerate soft food or a regular diet. (16) However, Walker and Syed found that patients who underwent harmonic scalpel tonsillectomy reported better dietary scores at 24 and 48 hours than did an electrocautery group. (14) Likewise, Oko et al found that harmonic scalpel patients had significantly better dietary scores than did blunt dissection patients on postoperative days 1, 5, 7, and 9. (22)

There was also no difference in the rate of return to normal activities in our study. Only one other study has previously analyzed activity as an outcome in harmonic scalpel investigation. Walker and Syed found that more harmonic scalpel patients returned to regular activities at 24 and 72 hours than did electrodissection patients. [14] However, this was significant only for patients younger than 7 years.

The outcomes we obtained in our study might have been influenced by a number of confounders. For one, patients were not randomized into treatment groups, and this might have resulted in a number of significant differences in baseline patient characteristics. For example, patients in the harmonic scalpel group were younger by a difference in the medians of 8.8 years (p = 0.006). It is also possible that patients who were operated on by different surgeons or at different hospitals might have received slightly different treatment and postoperative care. Finally, there was a higher proportion of patients in the harmonic scalpel group than in the monopolar diathermy group.

In conclusion, we found that the use of the harmonic scalpel for tonsillectomy resulted in significantly less intraoperative bleeding than did the use of monopolar diathermy, but there were no other clinically significant differences between the two techniques. Larger, randomized studies are needed to confirm or refute our findings and to help determine whether the harmonic scalpel offers any additional benefits over traditional tonsillectomy instrumentation.

References

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(15.) Willging JP, Wiatrak BJ. Harmonic scalpel tonsillectomy in children: A randomized prospective study. Otolaryngol Head Neck Surg 2003; 128(3):318-25.

(16.) Morgenstein SA, Jacobs HK, Brusca PA, et al. A comparison of tonsillectomy with the harmonic scalpel versus electrocautery. Otolaryngol Head Neck Surg 2002;127(4):333-8.

(17.) Potts KL, Augenstein A, Goldman JL. A parallel group analysis of tonsillectomy using the harmonic scalpel vs electrocautery. Arch Otolaryngol Head Neck Surg 2005;131( 1):49-51.

(18.) Hall MD, Brodsky L. The effect of post-operative diet on recovery in the first twelve hours after tonsillectomy and adenoidectomy. Int J Pediatr Otorhinolaryngol 1995;31(2-3):215-20.

(19.) Collison PJ, Weiner R. Harmonic scalpel versus conventional tonsillectomy: A double-blind clinical trial. Ear Nose Throat J 2004; 83(10):707-10.

(20.) Kamal SA, Basu S, Kapoor L, et al. Harmonic scalpel tonsillectomy: A prospective study. Eur Arch Otorhinolaryngol 2006;263 (5):449-54.

(21.) Leaper M, Mahadevan M, Vokes D, et al. A prospective randomised single blinded study comparing harmonic scalpel tonsillectomy with bipolar tonsillectomy. Int J Pediatr Otorhinolaryngol 2006; 70(8):138%96.

(22.) Oko MO, Ganly I, Loughran S, et al. A prospective randomized single-blind trial comparing ultrasonic scalpel tonsillectomy with tonsillectomy by blunt dissection in a pediatric age group. Otolaryngol Head Neck Surg 2005;133(4):579-84.

Jason A. Roth, BSc(Med), MBBS; Tobias Pincock, MBBS, FRACS; Raymond Sacks, MBBCh, FCS(SA)ORL; Martin Forer, MBBCh, FRACS; Neff Boustred, MBBCh, FCS(SA)ORL; William Johnston, MBBS, FRACS; Michael Bailey, PhD, MSc

From the Department of Otorhinolaryngology, Royal Prince Alfred Hospital, New South Wales (NSW), Australia (Dr. Roth and Dr. Pincock); the Department of Otorhinolaryngology, Concord Repatriation General Hospital, NSW (Dr. Sacks, Dr. Boustred, and Dr. Johnston); the Department of Otorhinolaryngology, Royal North Shore Hospital, NSW (Dr. Forer); and the Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Nursing, and Health Sciences, Monash University/The Alfred Hospital, Melbourne, Victoria, Australia (Dr. Bailey).

Corresponding author: Dr. Jason A. Roth, PO Box 39, Killara NSW 2071, Australia. Phone: [phone]; fax [phone]; e-mail: [e-mail]