Comparison of Serratus Posterior Superior Intercostal Plane Block and Paravertebral Block for Post-Thoracotomy Pain Management

Thoracotomy is a commonly performed approach in thoracic surgery and is associated with severe postoperative pain due to extensive tissue dissection and rib retraction. Inadequate control of postoperative pain may lead to serious complications, including impaired respiratory function, secretion retention, atelectasis, pneumonia, chronic post-thoracotomy pain syndrome, and reduced patient satisfaction . Therefore, identifying effective, safe, and sustainable analgesic strategies following thoracotomy is of critical importance for improving both patient comfort and clinical outcomes.

Thoracic epidural analgesia (TEA) has long been considered one of the most widely used techniques for postoperative pain control in thoracic surgery. Although TEA provides effective bilateral somatic and visceral analgesia, its clinical use is limited by several factors, including hypotension, urinary retention, motor blockade, epidural hematoma, technical challenges, and the requirement for patient cooperation. Consequently, in addition to systemic analgesics, regional anesthesia techniques have become essential components of multimodal analgesia protocols in thoracic surgery . This has encouraged the development of alternative approaches that are less invasive, technically more feasible, and capable of providing comparable analgesic efficacy. Fascial plane blocks, such as paravertebral block (PVB), erector spinae plane block (ESPB), serratus anterior plane block, and serratus posterior plane blocks, have gained increasing attention because they can be performed within more superficial anatomical planes and are associated with a lower risk of complications . These techniques are particularly considered safe alternatives in patients for whom epidural analgesia is contraindicated or technically challenging .

Thoracic paravertebral block (PVB), one of the techniques evaluated in the present study, provides effective control of both somatic and visceral pain through direct blockade of the thoracic spinal nerves. Despite its relatively deep anatomical location, PVB has demonstrated efficacy in numerous clinical settings and has been widely adopted in clinical practice. It has been successfully utilized in major thoracic procedures, including open thoracotomy, video-assisted thoracoscopic surgery (VATS), breast surgery, management of rib fractures, and extensive thoracic operations such as pneumonectomy and lobectomy. However, due to its deep anatomical location, PVB is associated with technical challenges and potential complications, including pneumothorax and vascular injury .

As an alternative approach, the Serratus Posterior Superior Intercostal Plane Block (SPSIPB) has emerged as a novel regional anesthesia technique offering a technically simpler and anatomically safer profile owing to its more superficial site of administration. This block is performed by injecting local anesthetic between the serratus posterior superior muscle and the second or third intercostal muscles. Following injection, the spread of local anesthetic may extend to the dorsal rami, lateral cutaneous branches of the intercostal nerves, and the paravertebral space. Consequently, SPSIPB can provide extensive sensory blockade covering dermatomes from T2 to T9 .

The potential of SPSIPB to achieve broad dermatomal coverage and provide segmental analgesia comparable to that of PVB has been supported by cadaveric studies and case series reported in the literature. Anatomical and technical descriptions have demonstrated that the sensory distribution of SPSIPB may extend from C3 to T10 dermatomes . Such extensive spread suggests that SPSIPB may provide effective analgesia for upper thoracic regions.

The analgesic efficacy of SPSIPB has also been demonstrated in procedures involving anatomical regions similar to thoracic surgery, including video-assisted thoracoscopic surgery (VATS), reduction mammaplasty, cardiac surgery, and pectus excavatum repair, as reported in several case studies and clinical reports. However, prospective studies directly comparing SPSIPB and PVB in patients undergoing open thoracotomy remain limited.

In this context, the primary objective of the present study is to compare the efficacy of SPSIPB and PVB in providing postoperative analgesia in patients undergoing thoracic surgical procedures performed via thoracotomy and to contribute to the optimization of postoperative pain management strategies in thoracic surgery.

Patients undergoing thoracic surgery via thoracotomy are required to remain in the lateral decubitus position for prolonged periods to facilitate surgical exposure. This positioning is considered one of the major contributors to postoperative shoulder pain, primarily due to the mechanical stress imposed on the non-dependent shoulder and scapulothoracic region. The resulting pain not only compromises patient comfort but may also delay early mobilization, thereby adversely affecting respiratory function and the recovery of postoperative pulmonary capacity . Therefore, the ability of regional anesthesia techniques used in thoracic surgery to provide sensory blockade extending beyond the surgical incision site to include dermatomes associated with the shoulder girdle has emerged as an important determinant of analgesic success.

Accordingly, the present study aims to comprehensively compare SPSIPB and PVB with regard to both the management of post-thoracotomy postoperative shoulder pain and their overall analgesic efficacy. Furthermore, the contribution of these two techniques to postoperative pain management will be thoroughly evaluated in terms of patient comfort and safety profiles.