The surgical anatomy of the small saphenous vein and adjacent nerves in relation to endovenous thermal ablation.

BACKGROUND: Thermal damage to peripheral nerves is a known complication of endovenous thermal ablation (EVA) of the small saphenous vein (SSV). Therefore, the main objective of this anatomic study was to define a safe zone in the lower leg where EVA of the SSV can be performed safely. METHODS: The anatomy of the SSV and adjacent nerves was studied in 20 embalmed human specimens. The absolute distances between the SSV and the sural nerve (SN) (closest/nearest branch) were measured over the complete length of the leg (>120 data points per leg), and the presence of the interlaying deep fascia was mapped. The distance between the SSV and the tibial nerve (TN) and the common peroneal nerve was assessed. A new analysis method, computer-assisted surgical anatomy mapping, was used to visualize the gathered data. RESULTS: The distance between the SSV and the SN was highly variable. In the proximal one-third of the lower leg, the distance between the vein and the nerve was <5 mm in 70% of the legs. In 95%, the deep fascia was present between the SSV and the SN. In the distal two-thirds of the lower leg, the distance between the vein and the nerve was <5 mm in 90% of the legs. The deep fascia was present between both structures in 15%. In 19 legs, the SN partially ran beneath the deep fascia. In the saphenopopliteal region, the average shortest distance between the SSV and the TN was 4.4 mm. In 20%, the distance was <1 mm. The average, shortest distance between the SSV and the common peroneal nerve was 14.2 mm. The distance was <1 mm in one leg. CONCLUSIONS: At the saphenopopliteal region, the TN is at risk during EVA. In the distal two-thirds of the lower leg, the SN is at risk for (thermal) damage due to the small distance to the SSV and the absence of the deep fascia between both structures. The proximal one-third of the lower leg is the optimal region for EVA of the SSV to avoid nerve damage; the fascia between the SSV and the SN is a natural barrier in this region that could preclude (thermal) damage to the nerve.

Surgical anatomy of the 10th and 11th intercostal, and subcostal nerves: prevention of damage during lumbotomy.

PURPOSE: In a descriptive, inventorial anatomical study we mapped the course of the 10th and 11th intercostal nerves, and the subcostal nerve in the abdominal wall to determine a safe zone for lumbotomy. MATERIALS AND METHODS: We dissected 11 embalmed cadavers, of which 10 were analyzed. The 10th and 11th intercostal nerves, and the subcostal nerve were dissected from the intercostal space to the rectus sheath. Analysis was done using computer assisted surgical anatomy mapping. A safe zone and an incision line with a minimum of nerve crossings were determined. RESULTS: The 10th and 11th intercostal nerves were invariably positioned subcostally. The subcostal nerve lay subcostally but caudal to the rib in 4 specimens. The main branches were located between the internal oblique and transverse abdominal muscles. The nerves branched and extensively varied in the abdominal wall. A straight line extended from the superior surface of the 11th and 12th ribs indicated a zone with lower nerve density. In 5 specimens the 10th and 11th intercostal nerves crossed this line from the superior surface of the 11th rib. In 5 specimens neither the 11th intercostal nerve nor the subcostal nerve crossed this extended line from the superior surface of the 12th rib up to 15 cm from the tip of the rib. CONCLUSIONS: Damage is inevitable to branches of the 10th or 11th intercostal nerve, or the subcostal nerve during lumbotomy. However, an incision extending from the superior surface of the 11th or 12th rib is less prone to damage these nerves. Closing the abdominal wall in 3 layers with the transverse abdominal muscle separately might prevent damage to neighboring nerves.

Development of a new trans-oral endoscopic approach for mediastinal surgery based on 'natural orifice surgery': preclinical studies on surgical technique, feasibility, and safety.

OBJECTIVE: In recent years, several surgical disciplines adopted endoscopic techniques. Presently, natural orifice approaches are under exploration to reduce surgical access trauma. We have developed a trans-oral endoscopic approach for endoscopic mediastinal surgery and have tested this new technique in preclinical studies for feasibility and safety. METHODS: We conducted an experimental anatomical study in fresh-frozen cadavers. By a midline, sublingual incision, we placed an optical scissor through a 6.0-mm trocar in the pretracheal region and created a working space; two additional trocars were placed by bi-vestibular incisions in the oral cavity. We visualized and followed the trachea down to the main bronchi. Paratracheal and subcarinal lymph nodes were resected bilaterally; the specimen could be removed through the midline channel. In an additional animal study in pigs, we tested the feasibility and safety for this surgical approach. Anatomical dissection allowed an estimate of collateral damage. RESULTS: In all cases, we could reach the target region endoscopically, and no conversion was necessary. Landmarks (the brachiocervical trunk, the azygos vein, and the pulmonary artery) were visualized easily and kept intact. A working space in the mediastinum could be established by the insufflation of air at 6-8mmHg. It was possible to harvest the specimen through the midline channel. Anatomical dissection of the cervical access route as well as of the mediastinal region showed no collateral damage. In the animal study, we encountered seroma of the surgical field due to the conditions of the animal model. The other outcomes with respect to pain and food intake were normal until the third postoperative day. No local infections occurred. Intraoperative gas exchange was normal and was not influenced by CO(2) insufflation with respect to blood gas analysis. CONCLUSION: These preclinical studies showed that the mediastinum could be reached by a trans-oral endoscopic approach, based on natural orifice surgery. Complete compartment resection of the paratracheal and subcarinal lymph node stations was possible in a well-defined and clearly visible working space. This approach may enhance the extent of mediastinal resections in oncologic surgery.