Comparison of thyroid surgery techniques: a retrospective cohort study and meta-analysis of traditional electric knife vs. straight bipolar electrocoagulation forceps
Highlight box
Key findings
• Straight bipolar electrocoagulation forceps reduce operation time, surgical trauma, and complications compared to the traditional electric knife.
• Patients undergoing surgery with straight bipolar electrocoagulation forceps experience faster postoperative recovery.
What is known and what is new?
• Traditional thyroidectomy using an electric knife is associated with higher risks of excessive bleeding and nerve injury.
• The use of straight bipolar electrocoagulation forceps in thyroid surgery shows improved intraoperative and postoperative parameters.
What is the implication, and what should change now?
• Straight bipolar electrocoagulation forceps should be considered as a preferred alternative to the traditional electric knife for thyroid surgery, given its benefits in reducing complications and enhancing recovery.
• Further prospective studies are needed to confirm these findings and refine surgical guidelines for thyroidectomy.
Introduction
Thyroid tumors are common diseases affecting the head and neck (1,2), and they are treated primarily through surgery (3-6). Although the surgical procedures can be performed to a reasonable degree in most hospitals, differences in surgical skill and instrumentation can affect the risk of excessive bleeding, recurrent laryngeal nerve, parathyroid injury, and other complications (7-10).
The present study aims to address these concerns by conducting a comparative analysis of intra- and postoperative parameters of thyroid surgery. We specifically focus on the utilization of two distinct surgical methods: traditional electric knife and straight bipolar electrocoagulation. These surgical techniques have significant implications for patient outcomes, including bleeding risk and nerve injury. However, there remains a need for further investigation and comparison of these approaches to guide clinical practice.
To provide a comprehensive analysis, this study combines a retrospective analysis of patients at our medical center with a meta-analysis of relevant literature. By integrating our own clinical data with existing evidence, we aim to offer valuable insights into the optimal approach for thyroid surgery. We present this article in accordance with the STROBE and PRISMA reporting checklists (available at https://gs.amegroups.com/article/view/10.21037/gs-24-103/rc).
Methods
Patients
Patients were selected for inclusion based on a retrospective analysis of 228 individuals who underwent thyroid surgery for the first time at the Head and Neck Department of Third Affiliated Hospital of Kunming Medical University between January 2014 and November 2018. The inclusion criteria encompassed patients diagnosed with nodular goiter, thyroid adenoma, or thyroid carcinoma (papillary carcinoma), see Table 1. This selection aimed to capture a representative sample of diverse thyroid pathologies encountered in clinical practice.
Table 1
| Characteristic | Traditional (n=150) | Bipolar electrocoagulation (n=78) | P | t/χ2 |
|---|---|---|---|---|
| Sex | ||||
| Male | 38 (25.33) | 12 (15.38) | ||
| Female | 112 (74.67) | 66 (84.62) | 0.08 | 2.967 |
| Age, years | ||||
| Male | 46.38±4.25 | 50.75±4.18 | 0.27 | 1.116 |
| Female | 43.76±3.18 | 45.17±1.52 | 0.17 | 1.379 |
| Thyroid disease | ||||
| Nodular goiter | 15 (10.00) | 5 (6.41) | ||
| Thyroid adenoma | 27 (18.00) | 9 (11.54) | ||
| Thyroid carcinoma (papilla carcinoma) | 108 (72.00) | 64 (82.05) | 0.25 | 2.798 |
| Type of surgery | ||||
| Unilateral thyroid surgery | 30 (20.00) | 10 (12.82) | ||
| Total thyroidectomy | 12 (8.00) | 4 (5.13) | ||
| Total thyroidectomy + level VI dissecting | 87 (58.00) | 49 (62.82) | ||
| Total thyroidectomy + level VI dissecting + unilateral neck dissecting (II–V) | 21 (14.00) | 15 (19.23) | 0.36 | 3.2 |
Values are n (%) or mean ± standard deviation, unless otherwise noted.
All surgeries were performed by the same surgical team, with same doctor serving as the primary surgeon and all procedures were conducted under the standardized protocols and techniques practiced by our surgical team. The choice between the surgery with traditional electric knife and thyroid surgery involving bipolar electrocoagulation was randomly allocated to patients, ensuring an unbiased selection. Of those patients, 150 underwent traditional electric knife, while the remaining 78 underwent bipolar electrocoagulation.
Informed consent was obtained from all patients prior to surgery. Patients had previously provided written consent for the anonymized use of their medical data for research purposes. This study was conducted in accordance with the Declaration of Helsinki (as revised in 2013), and was approved by the ethics committee of the Third Affiliated Hospital of Kunming Medical University (No. KYLX2023-056).
Surgical procedures
Surgical procedures were performed by the same team of clinicians and included various types of thyroidectomies. Preoperative evaluations, including fine needle aspiration cytology and B-ultrasonography, were conducted for suspected thyroid carcinoma cases.
Traditional electric knife surgery utilized an electric knife (model SY-03Y-B, Zhejiang Shuyou, China), while thyroid surgery involving straight bipolar electrocoagulation employed either Peng’s multifunctional surgical anatomy device [model SY-VIID (Q)-6, Zhejiang Shuyou, China] or an electrothermal alloy needle-type straight bipolar electrocoagulation forceps (model D5dyx, JNHZ Health Technology, China). Skin incisions were made based on patient age and neck anatomy, and the thyroid gland was dissected using bipolar electrocoagulation forceps. Hemostasis and tissue dissection were achieved using the electrocoagulation forceps (Figure 1).
During surgery, attention was given to preserving the recurrent laryngeal nerve and parathyroid glands. The recurrent laryngeal nerve was carefully exposed and protected during dissection, while the parathyroid glands were identified and preserved in situ. The anterior trachea ligament and isthmus were directly cut using bipolar electrocoagulation forceps, and the resection of the unilateral thyroid lobe was completed without sutures.
In cases requiring level VI, meticulous dissection was performed to expose and preserve the recurrent laryngeal nerve and parathyroid glands. Frozen surgical sections were examined by pathology as needed for intraoperative identification of the inferior parathyroid gland.
Data collection and analysis
Data were collected on total operation time, defined from the beginning of skin incision to the end of skin suturing; individual procedure duration, defined as the duration of a single procedure within the overall surgery; intraoperative blood loss; drainage on the first day after operation; hoarseness after operation; and numbness in hands and feet.
Data were analyzed using SPSS 16.0 (IBM, Chicago, IL, USA). Inter-group differences in continuous variables were assessed using Student’s t test, while differences in categorical variables were assessed using the χ2 test. Differences associated with P<0.05 were considered significant.
Meta-analysis of relevant literature
We performed a systematic search in PubMed (U.S. National Library of Medicine’s online database of biomedical articles) and FMRS (Foreign Medical Literature Retrieval Service, China) for studies published between October 2000 and October 2020. Keywords included: “thyroid surgery” and “bipolar”. When searching for literature in the FMRS database, Chinese characters for keywords are used. A total of 62 articles were found in the PubMed database, while 79 relevant articles were found in the FMRS database. Two independent authors screened titles and abstracts, followed by full-text reviews to select studies meeting inclusion criteria. Discrepancies were resolved by a third author. Eight studies were included, providing comparative safety outcomes between straight bipolar electrocoagulation forceps and traditional electric knife in thyroid surgery.
Data from eight studies were extracted by two authors using a standardized form. We used “metapack” package (11) in R for statistical analysis, 95% confidence intervals (CIs) were calculated.
Results
Surgical data
Patient data are summarized in Table 1. Patients with microcarcinoma without evidence of lymphoid metastasis underwent total thyroidectomy, while all patients with lymph node metastasis in level VI underwent resection of the central area of the thyroid isthmus, except two young patients. Patients with metastatic lymph nodes in lateral cervical regions 2–5 underwent lymph node dissection.
The two types of thyroid surgery were associated with significantly different total and individual procedure duration, intraoperative blood loss and drainage volume on the first day after operation (Tables 2,3, Figure 2).
Table 2
| Group | n | Operation time (min) | Intraoperative blood loss (mL) | Drainage volume on the first day (mL) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean ± SD | t | P | Mean ± SD | t | P | Mean ± SD | t | P | ||||
| Unilateral thyroid surgery | 7.871 | <0.001 | 6.818 | <0.001 | 1.958 | 0.057 | ||||||
| Bipolar electrocoagulation group | 10 | 31.20±3.26 | 5.12±3.46 | 19.30±3.34 | ||||||||
| Traditional electric knife group | 30 | 41.10±3.50 | 20.24±6.68 | 21.87±3.67 | ||||||||
| Total thyroidectomy | 6.032 | <0.001 | 8.208 | <0.001 | 2.099 | 0.054 | ||||||
| Bipolar electrocoagulation group | 4 | 42.01±3.46 | 10.15±3.23 | 25.25±1.76 | ||||||||
| Traditional electric knife group | 12 | 60.38±5.67 | 30.14±4.45 | 28.92±3.29 | ||||||||
| Total thyroidectomy + level VI neck dissection | 23.320 | <0.001 | 22.940 | <0.001 | 2.373 | 0.02 | ||||||
| Bipolar electrocoagulation group | 49 | 56.81±6.78 | 12.47±5.35 | 30.14±6.12 | ||||||||
| Traditional electric knife group | 87 | 80.35±4.91 | 40.25±7.46 | 32.33±4.55 | ||||||||
| Total thyroidectomy + level VI neck dissection + unilateral neck dissection (II–V) | 18.238 | <0.001 | 11.066 | <0.001 | 4.517 | <0.001 | ||||||
| Bipolar electrocoagulation group | 15 | 90.35±2.25 | 30.23±3.56 | 46.53±8.20 | ||||||||
| Traditional electric knife group | 21 | 125.45±7.18 | 50.38±6.36 | 63.62±12.88 | ||||||||
SD, standard deviation.
Table 3
| Group | Bipolar electrocoagulation | Traditional electric knife | P value | t |
|---|---|---|---|---|
| Unilateral thyroid surgery | <0.001 | 3.948 | ||
| Time (min) | 10.25±6.16 | 20.34±7.24 | ||
| n | 10 | 30 | ||
| Total thyroidectomy | <0.001 | 16.262 | ||
| Time (min) | 16.25±7.15 | 35.68±8.25 | ||
| n | 68 | 120 | ||
| Total thyroidectomy + level VI neck dissection | <0.001 | 8.238 | ||
| Time (min) | 12.12±5.25 | 20.68±7.26 | ||
| n | 64 | 108 | ||
Values are presented as mean ± standard deviation, unless otherwise noted.
Complications
Table 4 summarizes all complications clearly attributable to the surgery, which included hoarseness, hypocalcemia, numbness in hands and feet, and convulsions. Since blood was not routinely sampled from all patients, we identified hypocalcemia based on symptoms, rather than on serum levels of Ca2+. The two surgery groups did not differ significantly in incidence of hoarseness, but the incidence of hypocalcemia was significantly higher in the traditional electric knife group.
Table 4
| Complication | Bipolar electrocoagulation group (n=78) | Traditional electric knife group (n=150) | P value | χ2 |
|---|---|---|---|---|
| Hoarseness | 0.38 | 0.78 | ||
| Temporary | 3 (3.85) | 8 (5.33) | ||
| Permanent | 0 | 1 (0.67) | ||
| Hypocalcemia | <0.001 | 4.353 | ||
| Temporary | 8 (10.26) | 32 (21.33) | ||
| Permanent | 0 | 0 |
Values are presented as n (%), unless otherwise noted.
During follow-up of 220 patients during an average of 24 months, no cases of permanent hypocalcemia or permanent recurrent laryngeal nerve paralysis were recorded. Patients with numbness or convulsions of hands and feet were treated with 10% calcium gluconate intravenously, which relieved symptoms within 2 weeks. Patients with temporary hoarseness recovered in 1–3 months after the operation.
Meta-analysis of published data
Our meta-analysis, encompassing data from eight studies (the process flowchart in the Figure 3), corroborates these findings by demonstrating the superiority of bipolar electrocoagulation over the conventional electric knife in thyroid surgery outcomes. Specifically, our analysis involving 989 patients treated with bipolar electrocoagulation and 1,091 patients with the electric knife revealed a statistically significant reduction in total operation time with bipolar electrocoagulation (mean difference =−21.29 min, 95% CI: −26.32 to −16.27; P<0.00001), see Figure 4. Moreover, the comparison of intraoperative bleeding volumes between the two techniques, based on data from two studies comprising a total of 266 patients, indicated a significant reduction in bleeding with bipolar electrocoagulation (mean difference =−12.87 mL, 95% CI: −23.81 to −1.93; P=0.02), see Figure 5.
Discussion
This retrospective comparison of thyroid surgery involving the traditional electric knife or bipolar electrocoagulation provides evidence that using bipolar electrocoagulation can reduce total operation time by nearly 50% and intraoperative bleeding volume by 80%, without increasing risk of permanent hoarseness or hypocalcemia. The results of our study are consistent with a meta-analysis of eight studies from the literature (12-19). Our findings indicate that bipolar electrocoagulation enables precise surgical maneuvers, potentially resulting in reduced intraoperative bleeding and fewer postoperative complications. This advantage may be particularly beneficial in settings where resources are limited or where surgeons have varying levels of experience.
Straight bipolar electrocoagulation forceps dissolve and denature vascular proteins in tissues, combining coagulation and cutting in a single step, making such straight bipolar forceps ideal for fine dissection (17,20,21). These forceps may be superior to ultrasonic and electric knives because they can be operated like pens, reducing artificial jitter, and their working surface is needle-like, allowing micro-hemostasis and micro-cutting without thermal damage to neighboring tissue. These advantages may help explain the ability of such forceps to reduce intraoperative bleeding, which often occurs in traditional electric knife, even with skilled senior surgeons.
Straight bipolar electrocoagulation forceps may also reduce risk of accidental injury to the recurrent laryngeal nerve and parathyroid gland. These tissues can easily be damaged during their dissection on the back of the thyroid gland, because many branches of blood vessels can be treated only by compression and ligation (22). The fine surgical manipulations to protect these tissues are quite challenging with traditional clamp hemostasis and an ultrasonic knife, but our work suggests that the needle-like electrocoagulation forceps can perform the steps smoothly.
In our experience, the straight bipolar electrocoagulation forceps allowed most of the thyroid surgery to be completed with only a small incision, which depends on the minimum diameter of the tumor mass and is generally at least 3.5 cm. The forceps can provide hemostasis without the need to ligate most of the blood vessels. Performing these upper pole manipulations using conventional instruments, in contrast, is difficult and associated with greater risk of damage to high parathyroid glands. To compensate for this, some clinicians leave some upper polar tissue, but this can reduce the efficacy of radioiodine-based cancer treatment after thyroid surgery.
In comparison to conventional surgical instruments, the utilization of straight bipolar electrocoagulation forceps offers distinct advantages, particularly in delicate anatomical regions such as the ‘dangerous triangle’ of the thyroid capsule. Previous studies have demonstrated that this area, located between the inferior corner of the thyroid cartilage, the lateral wall of the trachea, and the lateral wall of the esophagus, poses a heightened risk of damage to the recurrent laryngeal nerve (22-24). The recurrent laryngeal nerve traverses through this region into the larynx, amidst numerous small blood vessels and adjacent to the Killian-Jamieson area, a vulnerable section of the esophageal wall situated beneath the pharyngeal constrictor muscle and annular pharyngeal muscle (25,26).
The observed advantages of bipolar electrocoagulation in our meta-analysis align with the finer surgical manipulations facilitated by the use of straight bipolar electrocoagulation forceps. These forceps allow for meticulous dissection and coagulation of connective tissue and tiny blood vessels under direct visualization, thereby reducing the risk of damage to the recurrent laryngeal nerve and minimizing intraoperative bleeding. Notably, despite the demonstrated efficacy of bipolar electrocoagulation, the significant heterogeneity among the included studies warrants further investigation to elucidate the underlying factors contributing to the variability in outcomes.
Conclusions
The bipolar electrocoagulation demonstrated significantly shorter total operation time and less intraoperative bleeding compared to the traditional approach. The study findings align with existing literature, suggesting that bipolar electrocoagulation allows for precise surgical maneuvers, potentially reducing bleeding and postoperative complications.
Acknowledgments
Funding: This study was supported by
Footnote
Reporting Checklist: The authors have completed the STROBE and PRISMA reporting checklists. Available at https://gs.amegroups.com/article/view/10.21037/gs-24-103/rc
Data Sharing Statement: Available at https://gs.amegroups.com/article/view/10.21037/gs-24-103/dss
Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-24-103/prf
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-24-103/coif). The authors have no conflicts of interest to declare.
Ethical Statement:
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
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