The effects of ultrasonic and electrosurgery devices on nerve physiology

Scalpel versus Electrocautery for Surgical Skin Incision in Open Carpal Tunnel Release

Background: Electrocautery is an option for skin incision for the neck, abdominal or inguinal surgery, but is not generally used for hand surgery. The aim of this study was to clarify whether electrocautery skin incision would be beneficial in open carpal tunnel release (OCTR). Methods: A total of 16 patients with carpal tunnel syndrome underwent skin incision for OCTR using either a scalpel (n = 9) or a microdissection diathermy needle (n = 7). Postoperative pain was assessed using a visual analogue scale (VAS 0-100 mm) daily from postoperative days 1 till 7. Results: The diathermy group reported higher VAS scores (mean 80 mm) on the first postoperative day versus the scalpel group mean of 35 mm (p < 0.001). We continued measuring pain for 7 days after the surgery and found higher VAS scores for the diathermy group in the first 6 days. Conclusions: The use of electrocautery is associated with greater pain score in the first postoperative 6 days following OCTR. Level of Evidence: Level III (Therapeutic).

Evolving Technologies for Tissue Cutting

This article reviews evolving and lesser known technologies for tissue cutting and their application in oral and maxillofacial surgery.

Lateral thermal spread induced by energy devices: a porcine model to evaluate the influence on the recurrent laryngeal nerve

BACKGROUND

Recurrent laryngeal nerve (RLN) paralysis is a frequently observed complication after esophagectomy, and thermal injury is considered to be one of the causes. The difference in the lateral thermal spread associated with the grasping range of various energy devices remains unknown.

METHODS

Ultrasonic devices (Harmonic® HD1000i and Sonicision™) and a vessel-sealing device (Ligasure™) were studied. We evaluated the temperature of these devices, the activation time required, and the thermal spread on porcine muscle when the devices were used with different grasping ranges (thermal spread study). In addition, we evaluated the influence of thermal spread by short grasping use of the energy devices on the viability of RLN in a live porcine model (NIM study).

RESULTS

In the thermal spread study, the temperature of the ultrasonic devices lowered as grasping range increased, whereas the highest temperature of Ligasure was observed when used with two-thirds grasping. The activation time of ultrasonic devices became longer as grasping range increased, whereas the grasping range did not influence the activation time of Ligasure. Thermal spreads 1 mm from the energy devices were unaffected by the grasping ranges. Although the temperature of the Ligasure was lower than that of the ultrasonic devices, thermal spread by Ligasure was significantly greater than that induced by the ultrasonic devices. In the NIM study, the activation of the Sonicision with one-third grasping range did not cause EMG changes at distances of up to 1 mm from the RLN, whereas applying Ligasure with a one-third grasping range 1 mm away from the RLN led to a critical result.

CONCLUSIONS

The grasping range did not influence the thermal spread induced by the energy devices. Ultrasonic devices may be safer in terms of lateral thermal spread to the RLN than Ligasure.

Safety assessment of the use of ultrasonic energy in the proximity of the recurrent laryngeal nerve in a porcine model

BACKGROUND

Advanced bipolar and ultrasonic energy have demonstrated reduction of operating time and blood loss in thyroidectomy. However, these devices generate heat and thermal dispersion that may damage adjacent structures such as the recurrent laryngeal nerve (RLN). This study was designed to evaluate the safety profile of the Harmonic Focus+^® (HF+) device through the evaluation of thermal injury to the RLN using different algorithms of distance and time with state of the art technology.

METHODS

25 Vietnamese pigs underwent activation of HF+ in the proximity of their RLN. They were divided into 4 groups according to activation distance (3 mm, 2 mm, 1 mm and on the RLN). Time of activation, time between tones of the ultrasonic generator, changes in the electromyographic signal using continuous nerve neuromonitoring, vocal fold mobility assessed by direct laryngoscopy and histological thermal damaged were evaluated.

RESULTS

None of the pigs had loss of signal in the electromyography during the procedure; only one pig had isolated transient decrease in amplitude and one increase in latency. One pig had transient vocal fold paresis in the group with activation on the nerve. Evaluation of the nerves by histology and immunohistochemistry did not show significant changes attributed to thermal injury.

CONCLUSIONS

The use of ultrasonic energy close to the RLN is safe, provided that activation time does not exceed the necessary time to safely transect the tissue.

Comparison of harmonic blade versus traditional approach in canine patients undergoing spinal decompressive surgery for naturally occurring thoracolumbar disk extrusion

Objectives

To assess feasibility of the harmonic Osteovue blade (HOB) for use in the soft tissue approach for dogs undergoing hemilaminectomy and to compare outcomes between dogs undergoing HOB or traditional approach (TRAD).

Methods

A prospective randomized clinical trial was performed using 20 client-owned dogs with thoracolumbar intervertebral disk extrusion requiring hemilaminectomy. Dogs were randomly assigned to HOB or TRAD. Neurologic function and pain scores were assessed pre-operatively. Intraoperative blood loss and surgical approach time as well as postoperative pain and wound healing scores were recorded. Additionally, neurologic recovery and owner perceived quality of life were recorded at day 10 and 30 postoperative.

Results

There was no significant difference in sex distribution, weight, age, preoperative neurological grade and pain score, and perioperative outcome measures between groups. Intraoperative total blood loss was minimal for HOB and TRAD (median: 0 ml (range 0–9) and 2.2 ml (range 0–6.8), respectively; p = 0.165) and approach times were similar (median: 7 min (range 5–12) and 8 min (range 5–13), respectively; p = 0.315). While changes in wound healing scores were similar, changes in postoperative pain scores and neurological function were significantly improved in the HOB compared to the TRAD group. Postoperative complications in the HOB group consisted of automutilation of part of the incision and development of a small soft, non-painful subcutaneous swelling in 1 dog each.

Conclusions

The HOB is a safe and effective tool for the soft tissue approach for routine spinal surgery in dogs and is associated with decreased pain and increased neurological function post-surgery.

A systematic review and meta-analysis of Harmonic Focus in thyroidectomy compared to conventional techniques

Introduction

Several meta-analyses have been performed comparing the use of a variety of ultrasonic devices in thyroidectomy to conventional procedures. These studies have shown the superiority of ultrasonic devices for most outcomes studied including faster operative time and less blood loss, and equivalent or better safety for recurrent laryngeal nerve paresis and hypocalcemia. The current work is the first to examine a single ultrasonic device specifically designed for thyroid surgery, the Harmonic Focus, in order to confirm its efficacy and safety in thyroidectomy.

Methods

A comprehensive literature search without language restrictions was performed for randomized clinical trials comparing Harmonic Focus and conventional clamp, cut and tie in thyroidectomy. Outcome measures included operating time, blood loss, post-operative pain, length of hospital stay, hypocalcemia and recurrent laryngeal nerve paresis. Risk of bias was analyzed for all studies. Meta-analysis was performed using random effects models with the inverse-variance method for mean differences of continuous variables and the Mantel-Haenszel method for risk ratios of dichotomous variables.

Results

A total of 14 studies met the inclusion criteria. Harmonic Focus reduced operative time by 29 min, a 31 % decrease (p < 0.001), intra-operative blood loss by 45 ml (p < 0.001), post-operative pain (p < 0.001), length of hospital stay by 0.68 days (p = 0.005), drainage volume by 29 ml (p = 0.01), and occurrence of transient hypocalcemia by 40 % (p = 0.001). There were no significant differences between Harmonic Focus and conventional procedures in rate of persistent hypocalcemia, or rates of transient and persistent recurrent laryngeal nerve paresis.

Conclusion

This is the first meta-analysis of Harmonic Focus in thyroid surgery. In agreement with meta-analyses previously performed on ultrasonic devices, use of the Harmonic Focus has been shown to be a more effective surgical procedure compared to conventional methods in thyroidectomy. The low occurrence of hypocalcemia and recurrent laryngeal nerve paresis confirms that Harmonic Focus can improve thyroidectomy efficiency without increasing the risk of complications.

Acute and subacute effects of the ultrasonic blade and electrosurgery on nerve physiology

Ultrasonic blades have been shown to cause less acute electrophysiological damage when applied near nerves than monopolar electrosurgery (ES). This study was performed to determine whether the acute nerve damage observed for ES, as well as the relative lack of damage observed for ultrasonic dissection, extends through a subacute timeframe. Muscle incisions were made in rat with the Harmonic^® Blade (HB) and ES at a distance of 2 mm from the sciatic nerve. Sham surgery was also performed which consisted of similar exposure of the sciatic nerve without use of an energized device. Electrophysiological function was assessed acutely over a 3-h period, and subacutely after a 7-day survival, by monitoring the sciatic nerve compound action potential (CAP), conduction velocity (CV), von Frey hair (VFH) stimulation force, leukocyte infiltration, and impaired axonal transport via β-amyloid precursor protein (β-APP) immunocytochemistry.

During the acute period, ES produced significantly lower CAP and CV, and higher levels of leukocytes and β-APP than sham, whereas the ultrasonic blade was not significantly different from sham, and had significantly lower VFH force than ES. After the subacute survival, ES continued to display significantly lower CAP and CV, and higher levels of leukocytes and β-APP than sham, whereas ultrasonic blade had higher CAP and CV than sham, and lower VFH than ES. This study confirms that incisions made with an ultrasonic blade cause less acute nerve damage than monopolar ES, and are comparable to sham surgery at a distance of 2 mm from the sciatic nerve. The negative effects of electrosurgery extend through at least a 7-day survival period, whereas subacute recovery after application of the ultrasonic blade was comparable to that of sham surgery. For surgical procedures in the vicinity of vital nerves, use of the ultrasonic blade represents a lower risk than ES for both acute and subacute neural trauma.

Comparison of ferromagnetic induction and bipolar electrosurgery and suction in corticotomies in pig cerebrum

INTRODUCTION

The effects of newer energy-based surgical dissection and coagulation modalities on cerebral tissue have not been investigated. Several instruments have been developed to address the limitations of traditional electrosurgical instruments in the nervous system. We compared the effects of standard bipolar electrocautery and suction (BPS) with those of a new ferromagnetic induction (FMI) device in corticotomies of pig cerebral tissue as assessed by magnetic resonance imaging (MRI) and histological analysis.

METHODS

Three adult pigs underwent bilateral corticotomies (3 cm long×1 cm deep) using both FMI and BPS. The acute cerebral tissue edema created by each method was measured on coronal volumetric T2-weighted MRI sequences immediately after surgery. A lateral thermal "damage index" was calculated by dividing the width of the visible T2 tissue edema by the measured depth. The radiographic damage indices with each method were compared statistically. Histological analysis of each incision was conducted to compare the extent of tissue damage.

RESULTS

MRI showed that the mean radiographic damage index of each corticotomy was significantly lower with the FMI (0.30 ± 0.02 (0.28-0.32)) than with the BPS method (0.54 ± 0.11 (0.42-0.64)) (p = 0.02). Histological analysis suggested a correlation with the radiographic findings as the FMI tissue samples demonstrated less adjacent tissue damage than BPS.

CONCLUSIONS

FMI appeared to cause less adjacent tissue damage than the BPS method in pig cerebral tissue based on quantitative radiographic and qualitative histological analysis. Future studies are needed to investigate the clinical implications of energy-based surgical dissection on cerebral tissue.

Biatrial neuroablation attenuates atrial remodeling and vulnerability to atrial fibrillation in canine chronic rapid atrial pacing

AIMS

We investigated the proposition that an intact cardiac nervous system may contribute to electrophysiological remodeling and increased vulnerability to atrial fibrillation (AF) following chronic rapid atrial pacing (RAP).

METHODS AND RESULTS

Baseline study was conducted prior to ablating right and left ganglionated plexuses (RAGP, LAGP) in 11 anesthetized canines (Neuroablation group) and in 11 canines without neuroablation (Intact GP). After being subjected to RAP (400 beats/min) for 6 weeks, animals were reanesthetized for terminal study. The ERP shortening typical of chronic RAP was significantly more pronounced in the Intact GP (baseline: 112 ± 12 to terminal: 80 ± 11 ms) than in the Neuroablation group (113 ± 18 to 102 ± 21 ms, p < .001), and AF inducibility (extrastimulus protocol) showed significantly greater increment in the Intact GP (baseline: 23 ± 19% to terminal: 60 ± 17% of trials) than in the Neuroablation group (18 ± 15% to 27 ± 17%, p = 0.029). Negative chronotropic responses to right vagus nerve stimulation were markedly reduced immediately after the neuroablation procedure but had recovered at terminal study. Vagally-evoked repolarization changes (from 191 unipolar electrograms) occurred in a majority of Intact GP animals in the superior, middle and inferior RA free wall, and in the LA appendage. In the Neuroablation group, repolarization changes were restricted to the superior RA free wall but none occurred in the inferior RA and only infrequently in the LA appendage, yielding significantly smaller affected areas in Neuroablation than in Intact GP animals.

CONCLUSION

Persistent functional denervation in LA and RA regions other than RA pacemaker areas may contribute to prevent the development of a tachycardia-dependent AF substrate.

[Wiedemann-Beckwith syndrome: a new approach for reduction glossoplasty using Ultracision(®)]

INTRODUCTION

A reduction glossectomy may be complicated by tongue and mouth floor edema and extend the recovery time for a normal tongue function. We performed reduction glossectomy using Ultracision(®), an ultrasonic vibrating device, so as to limit these complications.

TECHNICAL NOTE

We performed a keyhole glossoplasty under general anesthesia. The initial tongue incision was performed with a cold scalpel, then the glossectomy was continued with Ultracision(®) only. We also used CURVED SHEARS(®). We evaluated our preliminary results with 3 patients presenting with Wiedemann-Beckwith syndrome.

CONCLUSION

Ultracision(®) is a useful tool for intra-oral surgery, and should soon be more frequently used. It is an alternative to electrocautery for this type of surgery.

Sealing vessels up to 7 mm in diameter solely with ultrasonic technology

Introduction

Ultrasonic energy is a mainstay in the armamentarium of surgeons, providing multifunctionality, precision, and control when dissecting and sealing vessels up to 5 mm in diameter. Historically, the inability to seal vessels in the 5–7 mm range has been perceived as an inherent limitation of ultrasonic technology. The purpose of this study was to evaluate sealing of vessels up to 7 mm in diameter with an ultrasonic device that modulates energy delivery during the sealing period.

Methods

In ex vivo benchtop and in vivo acute and survival preclinical models, a new ultrasonic device, Harmonic ACE^®+7 Shears (Harmonic 7), was compared with advanced bipolar devices in sealing vessels 1–7 mm in diameter with respect of burst pressure, seal reliability, and seal durability. Lateral thermal damage and transection time were also evaluated.

Results

Ex vivo tests of Harmonic 7 demonstrated significantly greater median burst pressures than an advanced bipolar device both for vessels <5 mm in diameter (1,078 mmHg and 836 mmHg, respectively, P=0.046) and for those in the range of 5–7 mm (1,419 mmHg and 591 mmHg, P<0.001). In vivo tests in porcine and caprine models demonstrated similar rates of hemostasis between Harmonic 7 and advanced bipolar devices, with high success rates at initial transection and seal durability of 100% after a 30-day survival period.

Conclusion

Sealing 5–7 mm vessels is not a limitation of the type of energy used but of how energy is delivered to tissue. These studies document the ability of ultrasonic energy alone to reliably seal large vessels 5–7 mm in diameter, with significantly greater burst pressure observed in in vitro studies than those observed with an advanced bipolar technology when energy delivery is modulated during the sealing cycle. Furthermore, the seals created in 5–7 mm vessels are shown to be reliable and durable in in vivo preclinical studies.

Use of the harmonic blade scalpel as a novel technique for thoracoscopic resection of pediatric paraspinal masses in children

INTRODUCTION

Data support use of video-assisted thoracoscopic surgery (VATS) for safe and effective resection of paraspinal masses in children. Our aim was to describe outcomes following this operation using a novel technique and to compare its use with that of other established techniques.

SUBJECTS AND METHODS

We performed a retrospective chart review of all children (<18 years old) undergoing thoracoscopic resection of paraspinal masses in 2000-2011. Demographics, operative details, and clinical outcomes were summarized and compared between those undergoing resection using a Harmonic (Ethicon Endo-Surgery, Blue Ash, OH) blade scalpel (HBS) and those who did not.

RESULTS

Sixteen cases were identified (median age, 57.5 months; range, 2-204 months). Six cases (37%) underwent VATS with use of the HBS, and 10 (63%) did not. Demographic and clinical factors were well matched. Median tumor diameter was larger in the HBS group (49.2 cm(3) versus 18.7 cm(3); P=.07). Operative time was similar between groups (121 versus 138 minutes; P=.25), as was the estimated blood loss (10 mL versus 30 mL; P=.91) and chest tube duration (2.1 versus 1.8 days; P=.78). Three cases of Horner's syndrome developed in the standard resection group, and one complication occurred in the HBS group.

CONCLUSIONS

The Harmonic blade scalpel can be used as a simple alternative to standard dissection techniques for thoracoscopic resection of paraspinal masses in children.

Ultrasonic incisions produce less inflammatory mediator response during early healing than electrosurgical incisions

As the use of laparoscopic surgery has become more widespread in recent years, the need has increased for minimally-invasive surgical devices that effectively cut and coagulate tissue with reduced tissue trauma. Although electrosurgery (ES) has been used for many generations, newly-developed ultrasonic devices (HARMONIC® Blade, HB) have been shown at a macroscopic level to offer better coagulation with less thermally-induced tissue damage. We sought to understand the differences between ES and HB at a microscopic level by comparing mRNA transcript and protein responses at the 3-day timepoint to incisions made by the devices in subcutaneous fat tissue in a porcine model. Samples were also assessed via histological examination. ES-incised tissue had more than twice as many differentially-expressed genes as HB (2,548 vs 1,264 respectively), and more differentially-expressed proteins (508 vs 432) compared to control (untreated) tissue. Evaluation of molecular functions using Gene Ontology showed that gene expression changes for the energized devices reflected the start of wound healing, including immune response and inflammation, while protein expression showed a slightly earlier stage, with some remnants of hemostasis. For both transcripts and proteins, ES exhibited a greater response than HB, especially in inflammatory mediators. These findings were in qualitative agreement with histological results. This study has shown that transcriptomics and proteomics can monitor the wound healing response following surgery and can differentiate between surgical devices. In agreement with clinical observations, electrosurgery was shown to incur a greater inflammatory immune response than an ultrasonic device during initial iatrogenic wound healing.

Tissue effects in vessel sealing and transection from an ultrasonic device with more intelligent control of energy delivery

BACKGROUND

Ultrasonic surgical devices have been demonstrated to provide excellent hemostasis, efficient transection, minimal lateral thermal damage, low smoke generation, and no risk of electrical current passage to the patient. These benefits originate from the inherent characteristics of the ultrasonic mechanism, but further improvements were thought possible through optimization of the energy delivery during application. The study reported here compared a new ultrasonic device, Harmonic ACE®+ Shears with Adaptive Tissue Technology, with a commercial predicate device, Harmonic ACE® Shears (both Ethicon Endo-Surgery, Inc., Cincinnati, OH, USA).

METHODS

Devices were evaluated in an in vivo porcine model intraoperatively and after a 30-day survival period. Both devices were used to seal a variety of vessels 1-5 mm in diameter, and compared for hemostasis, histological thermal damage, and adhesion formation. Sealed vessels were evaluated ex vivo for burst pressure, and visual obstruction caused by plumage from device application was assessed quantitatively.

RESULTS

ACE+ produced significantly less thermal damage, had fewer adhesions, offered faster transection, involved less visual obstruction, and had higher burst pressures than the predicate device. All vessel seals, evaluated over the course of a 30-day survival period in pigs, remained intact.

CONCLUSION

The new Adaptive Tissue Technology algorithm assists the surgeon in achieving better control of energy delivery to the tissue, sealing vessels with supra-physiological burst pressures, and low thermal damage. These preclinical results with Harmonic ACE+ may translate into meaningful clinical benefits, providing greater precision along with more efficient and effective cutting and coagulation in open or laparoscopic procedures.