Cardiovascular diseases are one of the main causes of death worldwide. According to
pathological studies, heart defects occur in 4-7% of cases, and the most common defect
among the defects is damage to the mitral valve [1]. Significant advances in surgical
practice, instrumentation, tissue manipulation, and perfusion technology have made it
possible to perform mitral valve surgery using mini-approaches. Minimally invasive mitral
valve surgery has become the standard of care in some specialized cardiac centers around
the world due to its excellent results, even despite longer cardiopulmonary bypass times
and aortic occlusion. In 2008, P. Modi and co-authors, a meta-analysis has been published
in which the authors come to the conclusion that a minimally invasive approach for
correcting mitral valve pathology actually has significant advantages: early activation
of patients, shorter duration of stay in the recovery room, shorter wound healing times,
advantages in case of repeated interventions, less the number of bleedings and
purulent-septic complications compared to classical sternotomy [2]. But despite all the
advantages of this approach, severe pain after minimally invasive cardiac surgery
continues to remain a serious problem [3]. Acute pain occurs after dissection of the
chest, pleura and pericardium, compression of the intercostal nerve with a retractor, as
well as dissection of the intercostal and pectoral muscles during surgical access. It
limits breathing and cough in the postoperative period, which can subsequently lead to
hypoxemia, sputum stagnation, atelectasis, pneumonia, myocardial ischemia, slow recovery,
and also an increase in the length of hospitalization [4]. Therefore, additional emphasis
and attention is paid to protocols for early functional restoration and pain reduction
for this group of patients. There are protocols for "accelerated recovery after surgery"
(ERAS - Enhanced Recovery After Surgery), their use makes it possible to achieve shorter
stays in the intensive care unit, reduce hospitalization, improve treatment outcomes and
reduce financial costs. One of the components of ERAS is the use of additional pain
management modalities [5]. However, in cardiac surgery, traditional methods of regional
anesthesia, such as thoracic epidural anesthesia or paravertebral block, are not usually
used due to intraoperative heparinization and the associated higher risk of spinal or
epidural hematoma. Finding an optimal and effective pain management strategy for this
category of patients remains an unsolved problem today.
Intercostal nerve cryoablation is considered a relatively new treatment for postoperative
pain in patients undergoing minimally invasive mitral valve surgery. One of the first
studies of cryoneurolysis was conducted back in 1974 in thoracic surgery [9]. In 76
patients, the use of intercostal cryoablation resulted in a significant reduction in
postoperative opioid analgesic consumption. These results were subsequently confirmed in
several other studies and the data were retrospective. In 2000, a prospective randomized
controlled trial was published involving 30 patients who underwent minimally invasive
mitral valve surgery or minimally invasive coronary artery bypass grafting and underwent
intercostal cryoablation. According to the results, a decrease in postoperative pain
syndrome was observed, and less painkillers were required [10].
In the study O'Connor LA et al. In patients undergoing surgical stabilization of the
ribs, cryoablation of the intercostal nerves resulted in a 25% reduction in opioid
analgesics consumption compared with patients who received an extrapleural catheter, and
pain scores were reduced by 22% in the cryoablation group [7]. Similar results
(cryoablation made it possible to significantly reduce morphine consumption compared to
the control group and reduce pain)were also described inrecent retrospective studies
through 2023 in other patient groups: patients who have undergone pulmonary
resectionusing single-port thoracic video-assisted access, where cryoablation was used as
a method of postoperative pain relief [8] and patients undergoing lung transplantation
[12].
In the FROST study for 2021 the use of this method in patients with lateral thoracotomy
showed significant improvement in spirography parameters (FEV1, FVC) after 48 hours, as
well as 30 and 60 days after surgery [6]. Studying the influence of pain was not the main
objective of this work; pain was assessed using VAS and did not show a difference.
However, improvement in breathing parameters in the early postoperative period may
indirectly be associated with a lower level of pain and a more comfortable state of the
patient; the consumption of opioid analgesics was not properly assessed in this study.
In 2021Peter I Cha and others published a systematic review of 23 studies on the
effectiveness of intercostal cryoneurolysis in patients with pectus excavatum, lateral
thoracotomy, post-thoracotomy pain syndrome, traumatic rib fracture and chest wall
malignancy. Most studies have demonstrated a reduction in inpatient opioid analgesic use
with intercostal nerve cryoablation compared with traditional pain management techniques.
In patients requiring lateral thoracotomy, intercostal cryoablation results in decreased
opioid analgesic dosage (grade 2A) and improved pain scores (grade 2C) postoperatively
(PICO guidelines) [11].
Finding an effective and at the same time simple strategy for pain relief in the early
postoperative period in patients undergoing minimally invasive mitral valve surgery is an
urgent task; it is advisable to conduct a prospective clinical study with a
well-thought-out design in this direction.