3 Thoracolumbar Junction

10.1055/b-0035-121463

3 Thoracolumbar Junction

3.1 Retroperitoneal Extrapleural Approach to the Thoracolumbar Spine T9–L5 According to Hodgson

R. Bauer, F. Kerschbaumer, S. Poisel

3.1.1 Principal Indications

Scoliosis
Kyphosis
Vertebral body fractures
Tumors
Spondylitis

3.1.2 Choice of Side of Approach

Generally speaking, exposure of the thoracolumbar junction is possible using a right-sided as well as a left-sided approach. If the given indication does not prescribe the side to be used, the left-sided approach is preferable for anatomical reasons: the left dome of the diaphragm lies lower, and a right-sided exposure of the vertebrae is hampered by the liver and by the easily torn inferior vena cava. In cases of scoliosis, entry is made, as a general rule, from the side of the convexity.

3.1.3 Choice of Rib to be Resected

The standard approach in this technique, which is employed mainly in the surgical treatment of scoliosis, is at the level of the ninth or 10th rib. By resecting the 10th rib, T11 and possibly T10 can be reached; if the ninth rib is chosen for the approach, one naturally reaches a more cranial segment. In younger individuals with mobile ribs, it may be possible to gain access to the vertebra corresponding to the resected rib. If this should prove difficult, the segment close to the spine of the next higher rib is removed by the same approach. In favorable circumstances the following vertebrae can be reached:

Resection of the ninth rib: access to T9–L5
Resection of the 10th rib: access to T10–L5

3.1.4 Positioning and Incision

( Fig. 3.1 )

The patient is placed on the right side. The skin incision begins posteriorly near the midline and follows the course of the 10th rib as far as the costal cartilage, continuing obliquely and distally in the epigastric and mesogastric regions in the direction of the segmental nerves ( Fig. 3.2 ). It usually ends at a level between the umbilicus and the pubic symphysis. If only the thoracolumbar junction of the spine is to be exposed, the incision may be commensurately shorter. After transection of the skin, the incision is continued with a diathermy scalpel; visible vessels are immediately grasped by forceps and coagulated. Thorough hemostasis has to be assured during the operation. The latissimus dorsi is then transected along the course of the 10th rib ( Fig. 3.3 , see also Figs. 2.32 and 2.33). More distally, the external oblique muscle of the abdomen is split in the direction of the fibers, exposing the 10th rib ( Fig. 3.4 ).

During the ensuing operation, it proves advantageous first to expose the peritoneum from the side of the abdomen. The deep abdominal muscle layers (internal oblique and transversus abdominis) are generally forced apart by opening of the scissors, and two blunt hooks are inserted ( Fig. 3.4 ). The peritoneum, now visible in the depths, is retracted medially from the lateral abdominal wall with a cotton applicator. Further exposure of the deep abdominal muscle layers is carried out in the direction of the costal arch parallel to the course of the vessels and nerves with the aid of a director. In this fashion, the upper lumbar spine is exposed retroperitoneally ( Fig. 3.5 ). After this, the peritoneum is also detached from the inferior surface of the diaphragm.

**Fig. 3.2** Exposure of the nerve supply of the anterior abdominal wall. 1 Transversus abdominis 2 Internal oblique 3 External oblique 4 Rectus sheath, posterior layer 5 Pyramidalis 6 Rectus abdominis 7 Spermatic cord 8 Ninth intercostal nerve 9 Tenth intercostal nerve 10 Eleventh intercostal nerve 11 Subcostal nerve 12 Iliohypogastric nerve 13 Lateral cutaneous branches 14 Anterior cutaneous branches

**Fig. 3.3** Anatomical exposure of the operative area after transection of the skin and subcutaneous tissue. 1 Serratus anterior 2 Latissimus dorsi 3 External oblique X, XI Rib locations

**Fig. 3.4** Operative site after transection of the latissimus dorsi, serratus anterior, external oblique, and deep abdominal muscle layers. 1 Serratus anterior 2 External oblique 3 Latissimus dorsi 4 Internal oblique and transversus abdominis 5 Peritoneum with preperitoneal fat 6 External intercostal muscle X Rib

**Fig. 3.5** Transverse section at the level of the second lumbar vertebra. The approach for retroperitoneal dissection is identified by an arrow (right-sided approach). 1 Latissimus dorsi 2 Serratus posterior inferior 3 Intercostal muscles 4 Diaphragm 5 Lateral abdominal muscles 6 Rectus abdominis 7 Quadratus lumborum 8 Psoas major 9 Intrinsic muscles of the back 10 Diaphragm, medial crura 11 Left kidney 12 Right kidney 13 Right hepatic lobe 14 Gallbladder 15 Pancreas 16 Descending part of the duodenum 17 Duodenojejunal flexure 18 Jejunum 19 Transverse colon 20 Descending colon 21 Parietal peritoneum 22 Peritoneal cavity 23 Abdominal aorta 24 Inferior vena cava 25 Superior mesenteric vessels 26 Right renal vessels 27 Sympathetic trunk II Lumbar vertebra

**Fig. 3.6** Operative site after medial retraction of the peritoneum with its contents, revealing the psoas muscle. The peritoneum is split over the 10th rib along the dashed line. 1 External oblique 2 Internal oblique 3 Transversus abdominis 4 Psoas major 5 Ilioinguinal nerve X Rib

**Fig. 3.7** Operative site after resection of the 10th rib and opening of the thorax in its bed. The costal cartilage is transected along the dashed line. 1 Diaphragm with diaphragmatic pleura 2 Stump of the 10th rib 3 Cartilage of the 10th rib 4 Periosteum of the rib and costal pleura 5 Left lung, inferior lobe 6 Costodiaphragmatic recess 7 External oblique 8 Internal oblique 9 Transversus abdominis

Subsequently, the periosteum of the 10th rib is transected using cutting diathermy along its entire length ( Fig. 3.6 ), and the rib is then exposed with a raspatory in customary fashion. This is done in the direction of the fibers at the muscle insertion; that is, the rib is exposed cranially from posterior to anterior, and caudally from anterior to posterior. Finally, the 10th rib is divided transversely with a scalpel at the costochondral border, elevated, posteriorly transected with rib shears, and removed. The thorax is now opened by longitudinal division of the parietal pleura in the bed of the 10th rib (see Section 2.1.4, Figs. 2.4, 2.5, 2.6). By extending the thoracotomy incision, the remaining posterior part of the rib may be further exposed and resected if necessary near the costotransverse joint with a rib cutter. Enucleation of the head of the rib should be omitted since this can lead to severe bleeding. The costal cartilage is then divided with a scalpel; it will serve later as a landmark for wound closure ( Fig. 3.7 ).

The peritoneum having previously been stripped off the inferior surface of the diaphragm, the diaphragm can now be transected under vision in a curved line beginning at a point approximately 2 cm away from the rib attachment and extending posterior to the spine ( Fig. 3.8 ). Damage to the phrenic vessels and the branches of the phrenic nerve can thus be avoided ( Fig. 3.9 ).

It is advantageous to place occasional marking sutures, which facilitate perfect approximation during wound closure ( Fig. 3.10 ). A rib spreader is then inserted. The peritoneal contents and the lung are retracted manually by an assistant or with the aid of a suitable spatula.

**Fig. 3.8** Operative site after thoracotomy. The diaphragm is transected with the diathermy scalpel in a curved incision. 1 Diaphragm 2 Split cartilage of the 10th rib 3 External oblique 4 Internal oblique 5 Transversus abdominis

**Fig. 3.9** Schematic representation of the diaphragm with the vascular and nerve supply viewed from the cranial direction. 1 Aorta 2 Inferior vena cava 3 Superior phrenic artery 4 Pericardiacophrenic vessels 5 Internal thoracic vessels 6 Superior epigastric vessels 7 Musculophrenic vessels 8 Inferior phrenic vessels 9 Phrenic nerve

**Fig. 3.10** Operative site after thoracotomy and exposure of the left retroperitoneal space. 1 Psoas major 2 Quadratus lumborum 3 Diaphragm 4 Diaphragm, central tendon 5 Medial arcuate ligament 6 Lateral arcuate ligament 7 Ilioinguinal nerve 8 Iliohypogastric nerve 9 Ureter 10 Lung

**Fig. 3.11** Anatomical exposure of the diaphragm and the structures that traverse it. 1 Median arcuate ligament 2 Left crus 3 Right crus 4 Medial arcuate ligament 5 Lateral arcuate ligament 6 Twelfth rib 7 Esophagus and anterior vagal trunk 8 Aorta with celiac trunk and superior mesenteric artery 9 Inferior phrenic artery 10 Superior suprarenal artery 11 Middle suprarenal artery 12 Left gastric artery, esophageal branch 13 Lumbar arteries 14 Inferior vena cava 15 Phrenic nerve 16 Subcostal nerve 17 Sympathetic trunk 18 Greater splanchnic nerve 19 Iliohypogastric nerve 20 Ilioinguinal nerve 21 Genitofemoral nerve 22 Lateral cutaneous nerve of the thigh 23 Psoas major 24 Quadratus lumborum 25 Diaphragm, lumbar part 26 Diaphragm, costal part 27 Diaphragm, sternal part 28 Sternocostal triangle 29 Lumbocostal triangle 30 Tendinous center IV Lumbar vertebra

In the next step, the lumbar part of the diaphragm with the left crus is transected. To subsequently undertake the appropriate procedure, the following structures first need to be identified ( Fig. 3.11 ). The greater splanchnic nerve passes through the diaphragm with the ascending lumbar vein (or the azygos vein) between the medial and intermediate crus, and runs distally and medially to the celiac plexus. Somewhat more laterally, the sympathetic trunk passes through the diaphragm between the intermediate crus and the lateral crus. The left diaphragmatic crus is dissected approximately 1.5 cm above the lateral or medial arcuate ligament. Preferably, a grooved director or a curved clamp is inserted into the aortic hiatus directly underneath the diaphragmatic crus. The diaphragm is transected in the direction of the grooved director in such a way that the greater splanchnic nerve cranially and the sympathetic trunk caudally remain undamaged ( Fig. 3.12 ). Occasionally, segmental vessels or branches of the ascending lumbar vein have to be ligated and transected.

The retroperitoneal tissue and/or the parietal pleura on the spine is now elevated with forceps, and a scissor incision is made along the axis of the vertebral column. The parietal pleura is then slightly retracted bilaterally; a curved clamp is passed beneath the segmental vessels that run transversely over the vertebral bodies, and these are then transected between the ligatures ( Fig. 3.13 ).