Anatomical basis of modern thoracotomies: the latissimus dorsi and the "serratus anterior-rhomboid" complex

Analysis of the positional relationship of the long thoracic nerve considering clinical treatment

INTRODUCTION

The long thoracic nerve (LTN) has a risk of being damaged during chest surgery and should be considered when performing anesthesia such as a serratus anterior plane block (SAPB). We analyzed the relationship between landmarks-the fourth to ninth intercostal space (ICS) at the midaxillary line (MAL), through which the distal part of the LTN passes-and the LTN.

MATERIALS AND METHODS

We used 25 specimens from 17 embalmed Korean cadavers. The MAL, level of rib and ICS, and regions 5 cm anteroposterior to the MAL (aMAL/pMAL) were established to measure the position of the LTN crossing the MAL, pathway of the LTN, and entering points of the LTN to the SA.

RESULTS

The LTN crossed the MAL in 76% of the specimens. The LTN crossed the MAL within the fifth to sixth rib level in 70.8%. Seventy-six percent of the branches entered the SA within the fourth to sixth ICS. The fifth rib and ICS were the most frequent regions aMAL; however, several branches were found pMAL. The LTN entered the SA in 92.6% of the specimens within 3 cm anterior and 1 cm posterior to the MAL.

CONCLUSIONS

We set the danger zone as 4 cm near the MAL at the fourth to sixth ICS for thoracotomy. In addition, we proposed the fifth ICS in aMAL at the superficial plane as the alternative injection point for SAPB when blocking the LTN, and the fifth ICS in pMAL at the deep plane to prevent blocking the LTN.

Sequelae following axillary lymph node dissection for breast cancer

Axillary lymph node dissection (ALND) has a central role in the surgical management of breast cancer; however, it is associated with a potentially significant morbidity. Although post-ALND complications are often minor, in some cases they can persist for a long time following surgery, thereby affecting the quality of life of breast cancer survivors. Seroma formation and altered sensation of the upper limb are the two most common complications following ALND. Lymphedema is the most common potentially severe long-term complication following ALND. Major post-ALND complications (such as injury or thrombosis of the axillary vein and injury to the motor nerves of the axilla) are extremely rare. Meticulous surgical technique and careful selection of patients for postoperative radiation therapy are mandatory to prevent significant morbidity following ALND. The introduction of the technique of sentinel lymph node biopsy in clinical practice has resulted in a significant reduction in the incidence of post-ALND complications.

Muscle-splitting posterolateral thoracotomy: a novel technique

PURPOSE

In an effort to decrease the morbidity of a standard posterolateral thoracotomy, numerous muscle-sparing approaches have been developed. However, these incisions have been limited by the need for excessive muscle retraction with resultant neuropraxia, difficulty with exposure, and postoperative wound seroma. We report our results of a novel muscle-splitting thoracotomy incision, which affords excellent exposure without significant morbidity.

METHODS

We conducted a retrospective chart review of 37 consecutive patients who underwent "muscle-splitting" thoracotomy from June 1997 to June 1998. The technique, which involves a bidirectional spread of the latissimus dorsi and serratus anterior muscles, was performed by the same attending surgeon in all patients.

RESULTS

There were 22 male and 15 female patients, aged 26 to 81 (mean, 58), with a body mass index ranging from 18 to 40 kg/m(2) (mean, 25 kg/m(2)). Procedures included lobectomy/segmentectomy (19), wedge resection (5), pneumonectomy (2), Belsey IV fundoplication (5), Ivor-Lewis esophagogastrectomy (1), T8/T9 thoracic exposure (1), and miscellaneous thoracic cases (4). Operative time ranged from 90 minutes to 420 minutes (mean, 176), which was comparable with similar procedures through a standard incision. No patients required conversion to a muscle-cutting thoracotomy.

CONCLUSIONS

Our technique of muscle-splitting posterolateral thoracotomy appears to provide excellent operative exposure and to avoid problems seen with current muscle-sparing incisions. A prospective, randomized trial to compare this technique with a standard thoracotomy incision would be useful in determining its viability as an alternative thoracic approach.

Distal variations of the neurovascular pedicle of the serratus anterior muscle as a flap

The serratus anterior muscle has recently been suggested as a versatile and reliable flap for reconstruction of complex craniofacial and neck lesions, extremity and sacroiliac region injuries, as well as intrathoracic and extrathoracic reconstruction procedures. The muscle has been used as a microvascular flap or a pedicled transfer and has been transferred in combination with other muscles, bones, and skin. We performed 15 dissections of adult axilla regions that were examined under x3.5 loupe magnification to collect anatomic data regarding the neurovascular pedicle of the serratus anterior muscle. The serratus muscle and fascia were found to have a dual blood supply, with the upper part supplied by the lateral thoracic artery and the lower part by terminal branches of the thoracodorsal artery. The lateral thoracic artery was noted to supply the upper four slips but it extended into the lower serratus anterior muscle in two cases. Seven branching patterns were found in the lower serratus anterior muscle. In type I, the only branch of serrati proceeded over the long thoracic nerve. Type II had the only branch of serrati proceeding under the long thoracic nerve. In type III, double branches of serrati proceeded over the long thoracic nerve; while in type IV branches of serrati ran with a double branch under the long thoracic nerve. In type V, three serrati branches proceeded over the long thoracic nerve. Type VI serrati branches were branches of thoracodorsalis, which was hypoplastic, and the supply was maintained from the lateral thoracic artery. In type VII, one serrati branch ran over the long thoracic nerve. There was no connection between the branches of serrati and the branches of the lateral thoracic artery. The length of the long thoracic nerve, the number of motor axons and the vascular network in anatomic proximity to this nerve make it an expendable but powerful source of reconstructions of head, neck, chest wall and extremity defects. Results of this study provide an anatomic framework to improve current reconstructive or aesthetic procedures on the serratus anterior neurovascular structures.

Aetiology of rib stress fractures in rowers

Rib stress fractures are a common and significant problem in the rowing population. They occur in approximately 6.1 to 12% of rowers and account for the most time lost from on-water training and competition. This review discusses possible causative factors for rib stress fractures in rowers. Central to the establishment of causative factors is the identification that each rib forms part of a closed ring of bone that is completed anteriorly by the sternum and posteriorly by the thoracic vertebrae. Because of the shared sternum anteriorly each ring of bone is mechanically connected. Subsequently, during rowing individual ribs are not loaded in isolation, rather the rib cage is loaded as a complete unit. Incorporating this functioning as a complete unit a possible mechanism by which different factors contribute to rib stress fracture can be developed. In rowing, muscle factors generate loading of the rib cage. The characteristics of this loading stimulus are influenced by equipment, technique and joint factors. Rib-cage loading generates bone strain in individual ribs with the response of each rib depending upon site-specific skeletal factors. Depending on the characteristics of the bone strain in terms of the magnitude and rate of strain, microdamage may develop. The bone response to this microdamage is reparative remodelling. Whether this response is capable of repairing the damage to prevent progression to a stress fracture is dependent upon training and gender factors. Identification of these factors will generate a better understanding of the aetiology of this injury, which is required for improved prevention and treatment strategies.

Rare mononeuropathies of the upper limb in bodybuilders

Clinical and electrophysiological findings of mononeuropathies of thoracodorsal, dorsoscapular, terminal branch of suprascapular, and medial pectoral nerves are reported in 4 bodybuilders. All athletes used anabolic steroids. After about 1 year partial improvement of symptoms was evident in 2 cases and complete recovery in the other 2. The data are discussed in the light of the few other existing reports and possible pathogenetic mechanisms.

Anterolateral thoracic fascia: an anatomic and surgical entity

This anatomic study, based on six subjects, is aimed at a better description of the anterolateral thoracic fascia, not previously studied in its entirety. The literature describes a fascia of the pectoralis major m. continuous with that of the serratus anterior m., starting at the lateral border of the pectoralis major or pre-pectoral. The upper limits have never been studied and the lower limits are ill-defined, the aponeurosis of the pectoralis major or the pre-pectoral fascia being continuous with that of the rectus abdominis m. It is shown that this fascia, from a retropectoral origin, extends to the base of the axilla above and is stretched as bridge between the pectoralis major and latissimus dorsi mm. and the muscles of the anterolateral wall of the abdomen. This fascia has some surgical importance as a plane of coverage in the protection of mammary implants. The lack of concordance with classical anatomic accounts, the histology and the vascularisation of this fascia call for complementary studies.

Anatomic basis of serratus anterior muscle flap transposition

In order to explore the possibility of serratus anterior muscle (SAM) flap transposition in head, neck and thoracic surgery, we performed an anatomic study including 40 dissections of the muscle's vascular pedicle, the subscapular-thoracodorsal axis, which is a branch of the axillary artery. The SAM is characterized by its location: extending from the anterior and lateral aspect of the thorax to the medial border of the scapula; its easy surgical access; its constant and reliable vascularization by the thoracodorsal artery, a branch of the subscapular artery; its long arc of rotation allowing utilization of the SAM flap in head and neck and mediastinal surgery without microvascular anastomoses; its versatility in comparison with other perithoracic muscles. These considerations prompted us to use the SAM in head and neck reconstructive surgery; chest wall surgery, including chest wall reconstruction following resection for tumor and breast reconstruction; intrathoracic and mediastinal surgery, including reinforcement of high-risk tracheobronchial sutures or anastomoses, management of bronchopleural fistulas and empyema spaces, and repair of tracheo-esophageal fistulas and tracheal or esophageal defects.