Background: The mechanisms of persistent postoperative pain (PPP) with neuropathic features
after carotid endarterectomy (CEA) are multifaceted and are incompletely understood.
Objectives: The aim of this research was to assess whether the ultrasound-guided (USG)
intermediate cervical plexus block (ICPB) could provide better control of PPP and neuropathic
disturbances (NPDs) after CEA than the USG superficial cervical plexus block (SCPB).
Study Design: Prospective, randomized, controlled, clinical trial.
Setting: This clinical trial was conducted at the SS Filippo and Nicola Academic Hospital of
Avezzano (L’Aquila, Italy).
Methods: Patients who were scheduled for primary CEA were chosen. In the experimental
group, the USG-ICPB was performed unilaterally, at the level of the third cervical vertebra. The
needle was inserted into the deep lamina of the deep fascia of the neck, between the posterior
border of the middle scalene muscle and the anterior border of the posterior scalene muscle. Three
milliliters saline solution was injected into the opening of the deep lamina, and 20 mL 0.375%
levobupivacaine was injected. In the control group, the anesthetic target was located at the inferior
border of the sternocleidomastoid muscle at the level of the third cervical vertebra. The needle
was superficially inserted below the skin, and 2 to 3 mL saline solution was injected into the
opening of the superficial lamina of the deep fascia of the neck. A total of 20 mL 0.375% isobaric
levobupivacaine was subsequently injected.
The primary outcome measure was the proportion of patients with PPP on movement and at rest
3 months after surgery. The secondary outcome measures were NPD assessment scores using the
von Frey hair test and the Lindblom test, opioid and pregabalin consumption. Adverse effects were
also recorded.
Results: A total of 98 consecutive patients were enrolled and randomized to receive either a USGSCPB (control group, n = 49) or a USG-ICPB (experimental group, n = 49). The sensory blockade
was longer in the experimental group. Three months after surgery, the proportions of patients with
PPP on movement were significantly different between the experimental and control groups (33%,
95% confidence intervals [CI], 20%-47% vs. 71%, 95% CI, 57%-83%; P < 0.001), whereas
there were no differences in the proportions of patients with pain at rest between groups (31%,
95% CI, 18%-45% vs. 49%, 95% CI, 34%-64%; P = 0.063). The proportions of patients with
NPDs were not different between the groups, whereas the sizes of the areas of interest (cm2
) were
significantly different.
Limitations: A limitation of this study is that we assessed NPDs for only 3 months using the von
Frey hair test and the Lindblom test without additional instrumental techniques. Additionally, there
are many risk factors for NPDs after CEA. For this reason, another limitation of this research is that
we neglected to consider the relationship between the choice of anesthetic block and the presence
of these risk factors.Conclusions: The USG-ICPB provided long-lasting analgesia during the postoperative period and might mitigate the development
of NPDs, thereby decreasing the analgesic drug requirement.
Key words: Carotid endarterectomy, intermediate cervical plexus block, myofascial planes of neck, neuropathic disturbances,
persistent postoperative pain, superficial cervical plexus blocks, ultrasound guidance, vascular disease
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