Michalek, Pavel MD, PhD*; David, Ivan MD, PhD†; Adamec, Milos MD, PhD‡; Janousek, Libor MD‡
Total parathyroidectomy with partial autograft implantation into the forearm muscle is an elective procedure in patients with secondary hyperparathyroidism in chronic renal insufficiency or those with tertiary hyperparathyroidism after renal transplantation (1,2). The procedure is routinely performed under general anesthesia with endotracheal intubation (1); however, some patients are suitable for regional anesthesia. Kulkarni et al. (3) reported the use of a bilateral cervical plexus block; however, this technique may result in bilateral phrenic nerve block and laryngeal nerve block with acute respiratory insufficiency (4). Procedures involving the neck, upper extremity, and upper thoracic region may also be performed under cervical epidural anesthesia (CEA) (5–9). No study evaluating the possibility of performing a combined neck and upper extremity procedure under epidural anesthesia has been published.
The aim of the present pilot study was to test whether this combined procedure can be performed under CEA using 0.75% ropivacaine. We expected the following potential problems: (a) unsatisfactory analgesia of the cervical and upper thoracic dermatomes, (b) discomfort or dyspnea during deep preparation in the neck region, and (c) the possibility of unsatisfactory analgesia for evulsion of retrosternal parathyroid body.
Fifteen patients (6 men and 9 women) with a mean age of 58 (± 8) yr, undergoing total parathyroidectomy with partial parathyroid autograft implantation into the forearm muscle under CEA, were included in a prospective study during the 1999–2002 period. All patients gave informed consent, and the study protocol was approved by the local ethics committee. The indications for the procedure included secondary and tertiary hyperparathyroidism in 13 and 2 patients, respectively.
CEA was chosen because (a) the patient requested that the procedure be performed under regional anesthesia and (b) a previous neck procedure resulted in unilateral vocal cord paralysis.
We decided on unilateral vocal cord paralysis as an indication of CEA because of the possibility of monitoring vocal cord function through dialogue with the patient (early detection of wheezing or hoarseness) and to avoid tracheal intubation with the risk of vocal cord damage. The epidural puncture at the C6-7 intervertebral space was performed using the hanging-drop technique via a midline approach. Patients were in a sitting position with the head tilted forward. After location of the cervical epidural space, a catheter with a guidewire (Vygon, Germany) was advanced 4 cm cranially into the epidural space. The position of the catheter in the cervical epidural space was confirmed by a lateral epidurogram in the first three patients. Radiological check was performed to verify the position of the catheter tip at the level of C4 vertebra. Two milliliters of nonionic contrast medium iohexol (Omnipaque 300, Nycomed Imaging, Norway) diluted in saline (1:3) was used. The patients were laid supine, and after checking their vital signs, a test dose was administered. Standard local anesthetic solution was 10 mL of 0.75% ropivacaine plus 10 μg of sufentanil in 2 mL (total dose, 75 mg of ropivacaine), and the test dose was 3 mL of this solution. Vital signs (breathing, consciousness, noninvasive arterial blood pressure, and electrocardiogram) were monitored for 5 min after the test dose. In the absence of any vital sign deterioration, the remainder of the mixture was administered. The onset of sensory block/analgesia at C3 dermatoma was assessed with pinprick test (25-gauge short-beveled needle) at 5, 10, 15, 20, 25, and 30 min after local anesthetic application. The quality of analgesia, the extent of sensory block, and changes of the upper limb motion (brachial plexus motor fiber block) were evaluated 10, 20, 30 min, 1 h, and 2 h after the administration of the local anesthetic.
Motor block was assessed according to the following scale: 1 = absence of motor block, 2 = motor block almost complete (possible movement but not against resistance), and 3 = complete motor block (absence of movement).
Thirty minutes after local anesthetic application, a skin incision was made on the neck. All procedures were performed by the same surgeons, including procedures undertaken at the same period under general anesthesia (45 patients). Surgery was started by Kocher incision 2 in. above the jugulum, in parallel with axial plane, and demarcated by medial margins of sternocleidomastoid muscle. After subcutaneous tissue and muscular layer preparation, the thyroid gland was exposed, and parathyroid bodies were mobilized in their typical location. The bodies were removed, and a part of a body, marked with metallic clips, was implanted on incision on the forearm into the bundles of pronator teres muscle.
Throughout the procedure, the patients were sedated with midazolam (mean dose, 0.05 mg/kg IV). Vocal cord function was monitored by continuous verbal contact with the patient while the parathyroid glands were resected. Postoperative pain was assessed by visual analog pain scale (range, 0–10; 0 = no pain and 10 = maximal pain).
Perioperative hemodynamic monitoring was performed, including heart rate (HR) and mean arterial blood pressure (MAP) before the block and 30 min, 2, and 12 h after the administration of the local anesthetic (Table 1). MAP was measured by noninvasive arterial blood pressure cuff with an automatic device (Marquette, Germany).
The effect on respiratory variables was monitored by a bedside spirometry (spirometer MSP 3, Mesit Company, Czech Republic). Monitored respiratory variables included forced vital capacity (FVC), peak expiratory force (PEF), mean expiratory force (MEF), and forced expiratory volume per 1 s (FEV1) before the block and 30 min (before the start of surgery), 2, and 12 h after the administration of the local anesthetic (Table 1).
On completion of the procedure, postoperative analgesia was administered via the catheter using 0.2% ropivacaine at a rate of 2–4 mL/h. The catheter was removed 24 h after the procedure. Neurological function was not assessed during postoperative infusion of diluted ropivacaine.
Perioperative hemodynamic and respiratory changes were evaluated statistically using the Wilcoxon signed rank test and multiple comparison using Bonferroni method (BMDP Statistical Software, University of California, 1990). Differences of P value <0.05 were considered significant. All data are presented as mean ± sd.
All 15 procedures were successfully performed under CEA. The median time of duration of surgery was 75 min (45–90 min). No patient reported pain during the procedure. The analgesic effect of postoperative ropivacaine infusion was sufficient, with the mean postoperative visual analog pain scale of 0.4 ± 0.1.
The upper margin of sensory block was assessed in C2 dermatoma in all patients, and the median of the lower margin of sensory block was T3 (minimal extent C2-T1; maximal extent C2-T10). In all patients, the sensory fibers of cervical and brachial plexi were completely anesthetized. The median of the onset of sensory block was 15 min (10–25 min).
Bilateral partial motor block of the upper extremities was noted in one patient at the level 2 (decreased mobility of fingers, wrist, and forearm). The onset of motor block was 15 min after local anesthetic administration. The patient was not in distress during surgery and did not complain of dyspnea.
Hemodynamic variables demonstrated a statistically significant decrease in HR (P < 0.001) and MAP (P < 0.01), which was consistent with a sympathetic block of the heart and upper limbs. No vasopressor treatment was required for a decline in HR and MAP in our limited group.
FVC was decreased significantly (P < 0.001), whereas other variables stayed relatively stable: the changes in PEF, MEF, and FEV1/FVC ratio were statistically insignificant (P > 0.05) (Table 1). No patient complained of dyspnea during the procedure and in the postoperative period. There was no case of a new vocal cord paralysis (postoperative fiberoptic evaluation).
There was no case of dura mater puncture or blood observed in the catheter. One procedure was complicated by a subcutaneous infection at the site of the epidural puncture. The mean duration of hospital length of stay (LOS) for our patients was 3.3 ± 0.8 days (median, 4 days).
Our observations indicate that combined surgery on the neck and upper limb can be performed under CEA in a conscious state without causing discomfort to the patient. CEA is a relatively rarely used alternative for surgery involving the neck (carotid artery surgery or thyroid surgery) and upper limbs. The first to describe the technique of CEA was Dogliotti in 1933 (5) for thoracic procedures using a single-shot of local anesthetic solution (lidocaine). Bonnet et al. (6) published their series of 394 carotid artery procedures using CEA in 1990. They concluded that the CEA is a reliable and safe method for carotid endarterectomy. Hakl et al. (7) described the use of CEA in 215 patients who underwent carotid endarterectomy with conscious neurological monitoring. CEA was used also in a patient with aortic incompetence undergoing subtotal thyroidectomy (8) and for reconstructive hand surgery (9).
Administration of a local anesthetic (with an opioid) into the cervical epidural space results in anesthesia of the cervical plexus, brachial plexus, and superior thoracic dermatomes (10). CEA is usually performed with a catheter (10). It is frequently successful, providing high-quality anesthesia and postoperative analgesia of the above dermatomes. CEA also has a favorable effect on hemodynamic variables by blocking sympathetic innervation of the heart (11,12).
CEA is not used routinely in everyday anesthesia practice, mainly because of its potential serious complications, i.e., the possibility of local anesthetic administration into the subarachnoid space, bleeding with subsequent epidural hematoma formation, and infectious complications (epidural abscess). Bonnet et al. (6) noted, in a retrospective analysis of 394 patients, dural puncture in 2 (0.5%) and epidural venipuncture in 6 (1.5%) cases. Hakl et al. (7) reported migration of local anesthetic solution into subarachnoid space in 6 (2.8%), failed epidural puncture in 3 (1.4%), and blood observed in the epidural catheter in 4 patients (1.8%). Bilateral partial phrenic nerve block is also a possible complication of CEA. Bonnet et al. (6) reported respiratory muscle paralysis in 3 patients (0.8%). Our previous study (13) was designed to monitor the effect of regional anesthesia in carotid surgery on the respiratory variables using spirometry, analysis of blood gases, and ultrasound. In a group of 21 patients, there was a decrease in FVC by 17.6%, with the FEV1/FVC ratio remaining unaltered. There was no significant increase in Paco2 and no change in Pao2. Capdevilla et al. (14) assessed diaphragmatic function and respiratory pattern in 10 ASA I patients undergoing a procedure involving the upper extremity under CEA. The authors reported a reduction in FVC by 21.1%, a significant decrease in maximal inspiratory pressure, and an increase in Paco2 by 11.6%. The decrease in respiratory vital capacity owing to partial phrenic nerve block and paralysis of intercostal muscles are usually clinically irrelevant in patients without lung disease (13,14).
Among the side effects caused by blocking of the sympathetic nerves originating in the cervical and superior thoracic regions, the decrease in HR and MAP are usually beneficial for the patient because of prolonged coronary perfusion time and reduced left-heart afterload (11,12).
The possibility of monitoring the vocal cord movements using verbal contact with the conscious patient during surgery is a distinct advantage in the procedures involving parathyroid glands because of the course of the recurrent laryngeal nerve at the site of surgery. Damage to the recurrent laryngeal nerve with subsequent unilateral (or rarely bilateral) vocal cord paralysis is the most common neurological complication during this procedure (15).
These data and side effects could be tested in future studies evaluating the safety-efficacy comparison of CEA versus general anesthesia. The studies could consider the following points: (a) LOS, (b) length of intensive care unit stay, (c) hemodynamic and respiratory complications (myocardial ischemia and dyspnea), (d) quality of intraoperative and postoperative analgesia, and (e) incidence of postoperative vocal cord paralysis.
We conclude that, in the hands of an experienced anesthesiologist, CEA is a suitable choice and may be an alternative to general anesthesia for total parathyroidectomy, with implantation of a part of the parathyroid gland into the forearm muscles. The mean dose of ropivacaine in our patients was 75 mg, which was sufficient for block of the neck and upper extremity dermatomes.
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