Electrocautery burns of genitalia during lumbar spine surgery

1. Introduction

In this era of litigation, spine surgery is being aimed towards avoiding complications. Still many complications do occur intra-operatively related to use of instruments with advanced biomedical technology and one of these is electrocautery burns occurring intra operatively. Cautery has been used for thousands of years, since cavemen discovered that a burning stick could stanch bleeding and seal off a wound. Since the introduction of unipolar cautery by William T-Bovie in 1928 and bipolar cautery by Green Wood in 1939, a number of thermal complications have been recognized and reported in literature.^1,2 Although we use the “Bovie” almost daily our ignorance of the basic principles on which it operates is so deep that, for most of us, pressing the button to activate the electrosurgical unit constitutes an act of faith rather than the knowledgable application of scientific principles.³ (see Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6).

Fig. 1.

Schematic diagram showing completion of electrical circuit between the patient and the electrocautery unit through the grounding and active electrodes.

Fig. 2.

After revision Decompression and In-situ stabilization of L5-S1 spondylolisthesis using 6.5 mm pedicle screw and rod system, cautery burns over the penis and left knee were noticed.

Fig. 3.

After radical debridement and posterior lumbar interbody fusion of L4 L5 for postoperative discitis, full thickness burn was noticed over scrotum on the first postoperative day.

Fig. 4.

Older generation of electrocautery units with metal grounding electrode to be used after wrapping it in a wet cloth.

Fig. 5.

Electrocautery unit with rubber grounding electrode tobe used with intervening conductive gel.

Fig. 6.

New generation of electrocautery units with silicon grounding electrode.

Electrocautery unit has high frequency oscillators and amplifiers, generates high frequency current at the active electrode which is conducted through the surgical site of patient and the circuit is completed through grounding or indifferent electrode. The high frequency current at the surgical site is transformed into intracellular heat which will result in cutting or coagulation effect on tissues.

Electrosurgical cautery used in surgical practices can be broadly divided into Monopolar and Bipolar varieties. In monopolar electrocautery, the active electrode is small, mounted on a surgical hand piece and it produces very high current density and heat. The grounding or return or dispersive electrode or the indifferent plate or pad should be large to spread the current over large area, should be placed on trunk or thigh with good muscle envelope near the surgical site to decrease resistance from other tissues, should have an interposed conductive gel to decrease skin resistance and should remain in complete contact all the time to maximize energy in active electrode. A monopolar cautery can be used either as coagulation mode (non contact or contact coagulation) or cutting mode or cut coagulation blend mode. The amount of energy delivered to active electrode is same as that of the grounding electrode or indifferent plate but the current density is very much negligible due to small size of the electrode.

Bipolar electrocautery has two small and similar active electrodes very close to each other, mounted on a surgical hand piece (2 tines of a forceps) and does not use a separate indifferent or dispersive plate. The depth of injury is less which can be further decreased with saline irrigation and commonly used for hemostasis.

Three out of 19 cases of revision posterior Lumbo-sacral spine surgeries were planned and they included.

• 1.Revision of loose pedicle screws for spondylolisthesis of L₅-S₁.
• 2.Debridement and discectomy for discitis with recurrent herniation of L4-L5 disc
• 3.Removal of pedicle screw instrumentation from L₃-L₅

All 3 cases were operated in prone position over 2 transverse bolsters under GA & grounding electrode of electrocautery unit placed over anterior aspect of right thigh. All patients were found to have grade 1 and grade 2 burns of external genitalia (Penis) (4.3cmsx2.6 cms, mean surface area) during first post operative dressing. All patients were managed conservatively with elevation, antibiotics, anti-inflammatory drugs and regular dressings. Eventually electrocautery burns in all cases healed without any sequelae.

1.1. Case −1

A 45 year old man with lytic spondylolisthesis of L5-S1 was scheduled for revision of failed pedicle screw rod instrumentation, with patient in prone position under GA with the grounding electrode placed underneath anterior aspect of right thigh due to loosening of 5 mm pedicle screws. After successful revision to 6.5 mm pedicle screw and posterolateral bone grafting, cautery burn of the glans penis (4  cm × 3  cm, grade II) as well as left knee was noticed with surrounding edema on first postoperative day.

1.2. Case —II

A 35 year old male with post-operative discitis with recurrent disc herniation at L4-L5, was taken up for debridement and L4-L5 fusion with grounding electrode placed underneath the anterior aspect of right thigh. During the post operative period, a 5  cm × 2  cm, grade II burns over scrotum was noticed.

1.3. Case III

A 14 year old boy who had previously undergone L3-L5 posterior instrumentation, decompression and dural repair for L4-burst fracture with neurological deficits was taken up for pedicle screw removal. After successful retrieval of implant, edema and deformity of penis with 4  cm × 3  cm, grade II burns over the penis were noticed.

Burns in all 3 patients were treated conservatively with elevation antibiotic and analgesics and healed eventually.

2. Discussion

Even though intra-operative electrocautery burns occurs in developing countries, is rarely reported in the literature. Modern electrocautery devices are able to selectively cauterize the tissues by using a large grounding electrode.⁵

There are 4 possible mechanisms of electro cautery burns during surgery (^4,6,7).

• 1.Direct contact burns from imprecise use of active electrode,
• 2.Improper placement or attachment of grounding electrode is the commonest type of burns reported and can be serious.⁸ FDA has received 628 reports of grounding electrode site burns between Dec 1996–April 1, 998.⁹ A non contact grounding device, has been developed in cases of severe burns,¹⁰ but widespread usage and cost effectiveness in developing countries like India makes it impossible to use in every case. Grounding electrodes are prone to falling off the patient and monopolar energy may leak into the treatment table or pass into the treating clinicians.
• 3.Burns from heated up pooled solutions. They occur at both active and ground electrodes. and has been reported in the arthroscopy literature¹¹
• 4.Alternative site or capacitative coupling burns due to the apparent intra operative circuits eg: uninsulated surgical table contact with the patient.¹²

Most of our grounding electrodes were metallic ones & being kept over the anterior aspect of the thigh after wrapping the electrode with a wet cloth. Probably the wet cloth or the electrode itself might have come in contact with the penis leading to 2nd type of electro cautery burns. In all 3 cases electro cautery burns were noticed during the first post operative dressing at the end of 48 h.

In a study by Neufeld G.R and Foster K.R,¹³ to determine the optimal location of grounding electrode placement in head and neck procedures, they found that placing the electrode on the mid sternum, mid thoracic spine, lateral chest well and lower anterior abdominal quadrant resulted in lowest and roughly equivalent body deep tissue impedance values. They recommended grounding electrode placement close to the surgical site to reduce the incidence of electro cautery burns. As grounding electrode placement on thigh & forearm generates maximum impedance level, the authors suggest avoidance of this area.¹⁴ Hence malpositioned electrodes in our cases resulted in electro cautery burn. Many recommendations have been documented in the literature to reduce electro cautery burns such as using isolated electro cautery surgical units avoiding or minimizing contact between patient and surgical instrument and devices, avoiding activation of electro cautery when not in contact with the tissue and finally proper attachment & optimal placement of grounding electrode (^4,6,12).

In our cohort of spine surgery patients, the probable reasons for electrocautery burns include:

• 1.Displacement of the metal grounding electrode placed on anterior thigh due to intraoperative shifting of patient as a result of improper visualization of the surgical level of interest when operating on a conventional or partially radiolucent operating table with radiopaque metal obstacles
• 2.Intraoperative manipulation of spine resulting in dislodgement of metal grounding electrode leading to loss of firm contact between it and the skin
• 3.Displacement of metal grounding electrode as a result of the above reason directly coming in contact with redundant or hanging external genitalia of male patients positioned prone over bolsters on the operating table
• 4.Metal or rubber grounding electrode not completely confirming to the contour of the anterior thigh in a patient positioned prone and it's proximal inner corner dropping towards and contacting external genitalia of male patient continuously or intermittently due to intraoperative manipulation of the patient
• 5.Finally Antiseptic solution (Betadine10%, Wockhardt pharma, Bandra,Mumbai, India) used to clean surgical site or water from the wet cloth used to wrap the metal grounding electrode flowing towards upper and inner aspect of thigh and groin or flowing along the grounding electrode connecting cable coming in contact with glans penis or scrotum in prone position

3. Conclusion

Intra operative electro cautery burns, although relatively common are infrequently reported in the literature. Hence careful placement of grounding electrode with respect to complete contact around thigh or trunk and frequent checkup of electrocautery units and their electrical connections is recommended. Further investigation is needed to determine optimal grounding electrode placement with respect to surgical site as well as known indwelling hardware and optimal grounding electrode size with respect to patient's body surface area. Newer version of Silicon grounding electrodes will avoid these inadvertent electrocautery burns during spine surgery.