Comparing Surgical Outcomes with Scalpel vs N110A Microneedles in Oral and Maxillofacial Surgeries - RCT

Introduction

Oral and maxillofacial surgical procedures require planned incisions and these are traditionally done using scalpel blades, usually referred as ‘cold scalpels’. Historically, about 2000 years ago, these surgical blades were borrowed from domestic items and weaponry, in certain primitive societies.¹ Nevertheless, scalpel leads to excessive blood flow obscuring the visibility in operating field, and thus the practice to use additional vasoconstrictors to reduce local bleed, resulting in extra surgical time.¹ It does, however, has the advantage of a fine precise tip, ease of handling, low cost, and relatively uneventful and fast healing.²

Reducing blood loss (BL) holds significant importance in maxillofacial surgery. Use of electrocautery dates back to 1909, introduced by Cushing in fulgurating tumours.³ The use of electrocautery scalpel to open skin was questioned in the past for fear of delayed wound healing, wound dehiscence (due to thermal and tissue damage), or infection. The newer, finer-tipped electrocautery devices like the Colorado microdissection needle (CN) enable the use of smaller energy amounts, thereby reducing peri-incision tissue damage compared to traditional broad-tipped devices.⁴

The CN (manufactured by Stryker-Leibinger, based in Freiburg, Germany) was integrated into clinical practice.⁵ The length of the needle tip of the CN is a miniature cautery with a thin tip ranging from 1 to 5 microns in size. Constructed from delicately machined, insulated tungsten (with a melting point exceeding 3400 degrees Celsius), this diathermy needle is compatible with any standard cautery handpiece. Tungsten's durability maintains sharpness over time, reducing the necessity for multiple needles per case. Operating within a confined workspace, it enables finer and more precise incisions. Its benefits include effective hemostasis, minimal tissue damage, and reduced risk of wound dehiscence.⁵ Thus, it combines the advantages of both scalpel and cautery. While extensively documented in other surgical contexts such as abdominal and cranial procedures, its application in maxillofacial surgeries (both intraoral and extraoral approaches simultaneously in one study) remains largely unexplored, representing a gap in the existing literature.

To the best of authors’ knowledge, this study was the first in the literature investigating the extraoral and intraoral approaches made with the CN and cold scalpel in maxillofacial procedures. The present prospective randomized trial study was designed to evaluate the efficacy and safety of CN in comparison with conventional surgical blade in terms of speed of incision, visibility, blood loss (BL), effect on wound healing and scar assessment.

Materials and Methods

Between February 2022 to February 2024, 40 consecutive patients divided into two groups, Group A (CN) - 20 patients, Group B (Cold steel scalpel group) - 20 patients, were treated by the same surgeon. This was a randomised controlled prospective trial. The study was approved by the local institutional review board and the study was conducted adhering to Helsinki Declaration guidelines. All the patients were blinded to the surgical technique used and signed an informed consent before enrolment in the trial. The inclusion criteria were: 1. Patients consenting to participate in the study, 2. Patients aged 18 years and above undergoing maxillofacial surgery under LA/GA, 3. Patients belonging to ASA I and ASA II, 4. Extraoral and intra oral incisions. The exclusion criteria were: 1. History of keloids or hypertrophic scars, 2. Bleeding and clotting disorders, 3. Patient on anti-coagulants and anti-platelet therapy.

Allocation of subjects

The patients were randomly allocated to one of the groups by a third party not directly involved in the trial. All the surgeries were performed by a single designated operator for maintaining uniformity, while the relevant readings were recorded by the first operator who was blinded to the nature of the allotted group.

Operative procedure

All the patients were operated under general anaesthesia.

• Under proper aseptic conditions, the patient was painted with 2% povidone iodine intraorally or extraorally and draping was done.
• Site of incision was infiltrated with 2% lignocaine with 80,000 adrenaline.
• Electrocautery unit was set to 'cutting mode' and 'blend 1' (blend 1 comprises 75% cutting and 25% coagulation waveform) with a power range of 6 to 8 W.
• The intraoral or extraoral incision was given based on the surgical protocol with either CN (N110 microneedle) or cold steel scalpel.
• Using small weighing scale, gauge pieces were weighed before and after using to dab the area during incisions.

Follow-up routine

The follow-up was done after one week, two weeks, one month and three months.

Results

Type of incision in study subjects

In terms of the type of incision in study subjects In terms of the type of incision in the CN group, 10 participants received I/O incision, two each received Alkayat and Bramley incision, infraorbital incision, submandibular incision, Lateral eyebrow incision and Dingman incision. In the scalpel group, 10 participants received I/O incision, two each received infraorbital incision, submandibular incision, Lateral eyebrow incision and Dingman incision, while one each received Retro-mandibular incision and Alkayat and Bramley incision.

Visibility of incision in study subjects

Chi square test -19.969, P <0.001 indicating significance In terms of visibility at surgical site, intergroup comparison between the groups was statistically significant (P=0.001), with CN group showing better visibility.

Intergroup comparison of scar assessment between the groups

Chi square test - 4.579, P <0.043 indicating significance The intergroup comparison between the groups was statistically significant (P=0.043), with CN showing better results.

The wound healing observed during the 1st week was significantly better in CN group compared to scalpel group. On the 2nd week, the intergroup comparison between the groups was statistically significant (P=0.001), with CN demonstrating better result. At the one month and three month follow-up visits, the intergroup comparison between the groups was statistically non-significant (P=0.921).

Intraorally, wound healing on the 7th and 14th postoperative days exhibited significant superior outcomes with the CN compared to the scalpel. However, at one month and three month follow-up visits, the results were similar and not statistically significant. In contrast, extraorally, wound healing outcomes were comparable and non-significant between the scalpel and CN groups.

Comparison of BL between the groups

Independent t test -14.840, P <0.001 indicating significance. There was a significant variation in the bleeding between both the groups (Independent t test with P <0.05), where CN demonstrated less BL.

Comparison of speed of incision between the groups

Independent t test - 9.128, P <0.001 indicating significance. There was a significant variation in the incision speed between both the groups (Independent t test with P <0.05), CN showed greater speed of incision.

Discussion

Maxillofacial surgeries demand a delicate equilibrium between achieving hemostasis and minimizing tissue trauma, considering the significant concern surrounding extraoral scarring, particularly in young adults. During these procedures, excessive blood loss can precipitate severe complications. Additionally, ensuring optimal surgical site visibility and incision speed are crucial aspects of these surgeries. These factors not only affect duration of the procedure but also the extent of exposure to GA, underscoring their importance in achieving favourable surgical outcomes.

Working principle of electrocautery

Electrocautery in surgical procedures entails the application of high-frequency electrical current through body tissues, resulting in either cutting or coagulation effects.⁶ Currents of up to 500 mA can be safely administered to the patient. Heat is generated when the current is concentrated locally. The high-frequency current generated by the electrocautery machine is delivered to an active electrode held by the surgeon. In monopolar electrocautery, the current flows through the body and returns to the generator via a patient plate electrode. Modern surgical equipment typically offers cutting and coagulation modes with adjustable current intensities. In cutting mode, the generator delivers a continuous output, while in coagulation mode, it provides a pulsed output. The blend function, available only in cutting mode, allows for a combination of cutting and coagulation to enhance hemostasis during cutting.⁷ When using cutting mode, the current passage into tissues causes cellular fluid to vaporize, leading to the rupture of cell walls and tissue disruption.

The Colorado Micro Dissection Needle (CN), was introduced to clinical practice with a wide range of applications.⁸ A study conducted by Farnworth and colleagues in 1993 revealed that smaller electrodes deliver higher current density to the tissues, requiring less power to achieve the desired surgical effect. Consequently, this results in reduced dissipation of heat energy into the surrounding tissues, leading to less tissue necrosis, more precise cutting and hemostasis, and reduced smoke compared to conventional cautery devices.⁸ Electrosurgical procedures also allow for deeper penetration, reaching approximately 300-500 cell layers, and vaporize water in the underlying soft tissues, producing a "shrinking" effect.⁹ In the extraoral incisions, the depth is predetermined for the precision of the study. For extraoral incisions, the layers counted include the skin, subcutaneous tissue, superficial fascia, and the superficial part of the deep cervical fascia until reaching the muscle. However, in case of the lateral brow approach, the incision is through the skin, orbicularis oculi muscle, until the periosteum is reached. In contrast, for intraoral incisions, the layers counted include the mucosa, submucosa, until reaching the periosteum.

The speed of incision was measured as the time taken in sec/mm. After marking the skin incision, the time taken (in seconds) to complete the incision, including achieving hemostasis, was recorded. Only the CN tip was allowed to touch the marked incision, with the sides prohibited from touching the skin. Among the two groups, there is a notable disparity in incision speed.

Similarly, Zheng et al. (2022), reported that CN resulted in a shorter operative time compared to the conventional scalpel.¹⁰ These findings align with the results reported in other studies.

In this study, visibility at the surgical site was assessed using a modified Boezaart Scale,¹¹ where gauze dabbing was utilized instead of suction to control haemorrhage encountered during the incision. None of the 40 patients in the study had any other method employed for controlling haemorrhage. The modified scale graded the procedure accordingly. The results suggest that visibility was better with CN compared to scalpel. Notably, no other study has included this criterion when comparing incisions made using the Colorado needle and scalpel blade in maxillofacial surgeries.

In this study, mean Total Blood Loss (BL) was measured using small digital weighing scales and gauge pieces were weighed before and after using to dab the area during incisions. The difference in weight was considered equivalent to BL in mL. While ideally, the specific gravity of the patient's blood should be considered for this conversion, a standard figure of unit was used due to practical constraints. Although the subtraction of salivary components from the BL would have been optimal, it was not feasible due to time, cost, and technical requirements. However, each patient received premedication to minimize salivary secretions.⁸ In this study, BL was notably lower with the CN compared to the scalpel.

Similarly, Zheng et al. (2022) found that CN resulted in less BL in contrast to conventional scalpel.¹⁰ These findings align with the various studies, indicating the superiority of the CN in reducing blood loss compared to the conventional scalpel.

The Southampton Wound Healing Index¹² was employed to evaluate the healing of both extraoral and intraoral incision sites. This index utilizes a grading scale ranging from 0 to V. Grade 0 and I are indicative of good wound healing, while Grade II and III signify fair healing, and Grade IV and V denote unsatisfactory healing.

In this study, one patient in the Colorado group who underwent an intraoral incision experienced delayed wound healing. The patient reported a history of smoking and did not adhere to postoperative instructions. As a result, separation was observed during suture removal, necessitating the retention of sutures for a longer period to achieve wound closure. After one month, inflammation was present at one point, but normal healing with pinkish mucosa was observed at the three-month follow-up.

In the scalpel group, a single patient who underwent an intraoral incision exhibited a distinct wound healing pattern. Healing progressed normally up to the one month follow-up, but at the three-month follow-up, pus discharge from one point was observed. Plate removal was subsequently planned for this patient.

Two other patients in the same group experienced delayed wound healing (extraoral incision), attributed to their alleged inability to adhere to proper wound care protocols due to their low socio-economic status. However, all patients were successfully treated with specific antibiotics and regular dressing, particularly in cases involving extraoral incisions.

The results suggest that both the Colorado microdissection needle tip and conventional scalpel achieve comparable wound healing outcomes at three months. It can be deduced that the rate of wound healing may be slightly better when using the Colorado microdissection needle; nevertheless, further research may be warranted to confirm this observation.

Intraorally, wound healing on the 7th and 14th postoperative days exhibited significantly superior outcomes with the Colorado microdissection needle compared to the scalpel. However, at the one-month and three-month follow-ups, the results were similar and not statistically significant. In contrast, extraorally, wound healing outcomes were comparable and non-significant between the scalpel and Colorado groups.

Zheng et al. (2022) concluded that there was no substantial variance observed in wound healing, postoperative complication rate, or duration of hospital stay between the CN and scalpel groups.¹⁰

Rampalli Viswa Chandra et al. (2021), opined that the lack of thermal stresses in the tissues and the ability to precisely split the papilla in the surgical blade group may have resulted in better papillary healing over the CN and electrocautery.^9,13-15 At six months, the CN showed better papilla height gain over electrocautery when compared to the surgical blade, but this variance was not statistically significant.

In this study, scar assessment was conducted at three months using the criteria developed by Quinn et al.¹⁶ The intergroup comparison demonstrated statistically significant results with Colorado micro dissection needle being the superior one.

Milan Modi et al. (2021) observed that the Colorado micro dissection needle resulted in narrower scars and superior scar quality compared to the cold steel scalpel.¹⁷ They found a statistically significant difference in scar width between the Colorado micro dissection needle and cold steel.

On the other hand, Praveen Satish et al., (2019) discovered no notable distinction in scar appearance at 15 days and six months postoperatively between the two groups.¹⁸ However, they did note some significant difference between the Colorado group and scalpel group by the conclusion of the one-month period, where the scalpel showed better results than the Colorado microdissection needle.

Various limitations of the present study should be acknowledged. Firstly, the small sample size restricted the generalizability of the findings to a broader population. Secondly, the study was performed at a one center, potentially restricting the external validity or generalizability of the findings to other settings or populations. Thirdly, the study did not specify the type of suturing technique and the type of suture used, which could potentially influence wound healing outcomes. Additionally, the study did not include an assessment of pain, which is an important parameter often considered in surgical studies. Including pain assessment might have provided further understanding of patient experience and recovery. Furthermore, patient cooperation post-surgery was not considered, which could impact wound healing outcomes. Lack of patient compliance with Eric’s arch bar and IMF postoperative care, including oral hygiene and wound care, can contribute to complications such as wound dehiscence, irrespective of the incision technique used. These limitations should be considered when interpreting the study findings and designing future research in this area.

The findings suggest that utilizing the CN offers several advantages. Firstly, it can potentially reduce BL, thereby lowering the risk of complications. Secondly, it may cause minimal tissue damage, leading to improved scar outcomes and quicker recovery times. Thirdly, it could enhance visibility and precision for the surgeon, resulting in superior surgical outcomes. Additionally, the speed of incision is higher with CN. While the study had limitations like a small sample size and being conducted at a single center, the findings align with prior research indicating the superiority of the CN over conventional scalpels in various surgical procedures. However, further research is warranted to specifically evaluate the efficacy of the Colorado tip in maxillofacial surgery.

Conclusion

Based on the results of this study, it is evident that the CN offers significant benefits compared to traditional scalpels in maxillofacial surgeries. Specifically, it reduces blood loss and enhances visibility at the surgical site. Given the critical role of blood loss and surgical duration in determining surgical outcomes, these improvements are noteworthy. Moreover, there are notable difference in wound healing and scar formation between the two groups, further underscoring the benefits of the CN. Consequently, it can be used as an alternative or adjunct to conventional surgical scalpels, aiming to minimize blood loss, shorten incision time, promote better wound healing and visibility during surgery. Future research, particularly involving larger and more varied demographics with extended follow-up durations, would provide further understanding into its effectiveness.

Financial support and sponsorship

Nil

Conflicts of interest

There are no conflict of interest

Acknowledgement

The authors thank the individuals whose participation made this study possible. No external funding and support of the authors’ institution, was available for this study. The authors have stated explicitly that there are no conflicts of interest in connection with this article.