INTRODUCTION:
After thyroid diseases, hyperparathyroidism is one of the most common
endocrine surgical disease [1]. It occurs either from a disorder
within the parathyroid glands (primary hyperparathyroidism) or disorder
outside the parathyroid glands (secondary or tertiary
hyperparathyroidism) [2]. In recent years, since described by Kocher
in the late 1980’s, treatment of hyperparathyroidism was the surgical
removal of 4 parathyroid glands with transcervical incision [2-4].
After, realisation of that a single adenoma is the cause of
hyperparathyroidism in most of the patients (80-85%), surgical
management was changed significantly [2]. With preoperative imaging
tools (ultrasound and technetium-99m sestamibi scintigraphy) for
localisation of the adenoma and intraoperative parathyroid hormone level
measurements for confirmation, surgical excision of the offending
parathyroid adenoma is still accepted as the main treatment of primary
hyperparathyroidism[1,2,5].
The increasing diagnosis of thyroid pathologies in early stages and a
societal emphasis on physical appearances, especially in young women,
have been led to development of new surgical techniques alternative to
conventional transcervical incision consistently [3,6]. Over the
last two decades, so many techniques such as Open Minimally Invasive
Parathyroidectomies (OMIP), Minimally Invasive Video-Assisted
Parathyroidectomy (MIVAP) and pure Endoscopic Minimally Invasive
Parathyroidectomy (EMIP) and recently transoral endoscopic
parathyroidectomy vestibular approach (TOEPVA) have been developed
[3,7].
Here, we describe our anaesthesia experience for parathyroidectomy with
Transoral Endoscopic Parathyroidectomy by Vestibular Approach (TOEPVA).
According to our knowledge, this is the first report that explain
anaesthesia management in TOEPVA.
Methods: Seven patients undergo TOEPVA at the Health Sciences
University Izmir Bozyaka Training and Research Hospital between November
2018 and April 2019. All patients were diagnosed with primary
hyperparathyroidism due to a solitary parathyroid adenoma, and were
managed by the same anaesthetist and by the same experienced surgeon on
minimally invasive and endocrine surgery. Demographic data, drugs used
for anesthesia management (induction, maintenance and extubation),
hemodynamic parameters, end tidal carbondioxide and pulse-oximeter
values, additional agents used preoperatively in anesthesia management
and preoperative and peroperative measurements of PTH levels were
recorded prospectively and evaluated retrospectively.
Preoperative setting: After informed consent of patient was
approved for anaesthesia, all patients received preoperative anaesthesia
evaluation, including laboratory tests and imaging studies (chest
radiography, focused ultrasound for parathyroid adenoma mapping). Also
preoperative PTH levels were obtained to compare intraoperative rapid
parathormone levels. All patients received amoxicillin-clavulanic acid
(1.2 gr) 30 minutes before the incision as antibiotic prophylaxis.
Anaesthesia management: After routine monitorization
(Non-invasive blood pressure, electrocardiogram, end tidal carbondioxide
and pulse-oximeter), anaesthesia was induced with propofol (2mg/kg),
remifentanil infusion (0.01-0.5 mcgr/kg/min) and rocuronium (0.6mg/kg)
was administered to facilitate the tracheal intubation. Airway patency
was achieved by nasal intubation with an inner diameter of 6.5 mm spiral
endotracheal tube in six patients and with an inner diameter of 6.0 mm
spiral endotracheal tube in one patient. Eyes were carefully closed to
keep them closed peroperatively and to prevent contact with the solution
(chlorhexidine and povidone iodine) used to clean the vestibular area.
Dexametazone (8mg) and H2 blocker (50 mg) were applied
to all cases after anesthesia induction as routine clinical practice.
Anaesthesia was maintained with desflurane 5% to 6% concentration in a
gas mixture consisting of 45 % oxygen in air. All patients were
ventilated on
volume control ventilation mode with 5-7 mL / kg tidal volume and
respiratory rate was modified to keep the end tidal carbondioxide within
the normal values. Pulse-oximeter values were changed between 96-100%
in all patients peroperatively. Neuromuscular blocker dose was repeated
every 30 minutes routinely and also administered as rescue bolus dose if
the view of surgical field was worsened. After removal of parathyroid
adenoma, which was verified by histopathological examination and by
blood PTH level decrease, we administered contramal as 0.3 mg/kg
intravenously for postoperative analgesia. At the end of the operation,
sugammadex (2-4 mg/kg) was administered to reverse the neuromuscular
block. All patients transferred to Post Anaesthesia Care Unit (PACU) at
the end of the operation and to their ward one hour after PACU stay,
uneventfully.
Surgical management: All patients were operated by the same
principles of TOEPVA which was described by Anuwong at al (8). In
detail, the patient is placed in a supine position with slighlty neck
extention. After a proper surgical preparation, a 10-11 mm transverse
incision is made at the center of the oral vestibule just below the
vermilion border. Once the periosteum is approached and identified by
electrocautery and blunt dissection through the central incision the
neck area is injected with 20 to 40 mL diluated epinephrine (0,5 mg
epinephrine in 500 mL saline) by a Veress needle. About 2,5 cm distance
from this central incision two additional 5mm vertical incisions are
made on both sides, above and as lateral as possible to the canine teeth
to avoid mental nerve injury. These lateral trocar sides are also
prepared by injection with the same diluated epinephrine solution of 5
to 10 mL. Then, one central 10-11mm and two lateral 5mm trocars are
inserted and CO2 insufflation is began at a maximum
pressure of 6 mmHg with a flow rate of 6 L/min to create an air pocket
to perform parathyroidectomy with ordinary laparoscopic instruments.
Results: The patients characteristics, preoperative, operative
and postoperative details are shown in Table 1. Two patients (Case 1
(Heart rate: 43/min) and Case 5 (Heart rate: 41/min)) required atropine
(0.5 mg) and one patient (Case 2) (Blood pressure: 60/40 mmHg) required
ephedrine (10 mg) administration during insufflation. While all patients
require lower dose remifenantil infusion during drapping and preparation
for surgery after induction of anaesthesia; required higher doses
remifentanil during hyrodissection. Except insufflation and
hyrodissection phases of surgery, patients hemodynamic parameters were
stable (changed ±20% from baseline) during the operation time. Changes
in mean arterial pressure and heart rate in cases by the operation time
were shown on Figure 1 and Figure 2 respectively. No conversion to
conventional open surgery was necessary. In all patients, intraoperative
parathyroid hormone level decrease was confirmed by laboratory test.