Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice

The extent of analgesia provided by transversus abdominis plane blocks depends upon the site of injection and pattern of spread within the plane. There are currently a number of ultrasound-guided approaches in use, including an anterior oblique-subcostal approach, a mid-axillary approach and a more recently proposed posterior approach. We wished to determine whether the site of injection of local anaesthetic into the transversus abdominis plane affects the spread of the local anaesthetic within that plane, by studying the spread of a local anaesthetic and contrast solution in four groups of volunteers. The first group underwent the classical landmark-based transversus abdominis plane block whereby two different volumes of injectate were studied: 0.3 ml.kg(-1) vs 0.6 ml.kg(-1). The second group underwent transversus abdominis plane block using the anterior subcostal approach. The third group underwent transversus abdominis plane block using the mid-axillary approach. The fourth group underwent transversus abdominis plane block using the posterior approach, in which local anaesthetic was deposited close to the antero-lateral border of the quadratus lumborum. All volunteers subsequently underwent magnetic resonance imaging at 1, 2 and 4 h following each block to determine the spread of local anaesthetic over time. The studies demonstrated that the anterior subcostal and mid-axillary ultrasound approaches resulted in a predominantly anterior spread of the contrast solution within the transversus abdominis plane and relatively little posterior spread. There was no spread to the paravertebral space with the anterior subcostal approach. The mid-axillary transversus abdominis plane block gave faint contrast enhancement in the paravertebral space at T12-L2. In contrast, the posterior approaches, using both landmark and ultrasound identifications, resulted in predominantly posterior spread of contrast around the quadratus lumborum to the paravertebral space from T5 to L1 vertebral levels. We concluded that the pattern of spread of local anaesthetic differs depending on the site of injection into the transversus abdominis plane. This may have important implications for the extent of analgesia produced with each approach.

Studies on the spread of local anaesthetic solution in transversus abdominis plane blocks

Essentials of Our Current Understanding: Abdominal Wall Blocks.

Littre hernia is the protrusion of a Meckel diverticulum through a potential abdominal opening. Alexis de Littre (1700) reported ileal diverticula and attributed them to traction. August Gottlieb Richter (1785) defined them as preformed, and Johann Friedrich Meckel (1809) postulated their embryologic origin. Sir Frederic Treves (1897) distinguished between Littre and Richter hernia (partial enterocele). Embryologically, Meckel diverticulum is the persistent intestinal part of the omphaloenteric duct through which the midgut communicates with the umbilical vesicle until the fifth week. It is found at the antimesenteric border of the ileum, usually located 30 to 90 cm from the ileocecal valve, measuring 3 to 6 cm in length and 2 cm in diameter. Usual sites of Littre hernia are: inguinal (50%), umbilical (20%), and femoral (20%). Meckel diverticulum may be accompanied in the sac by the ileal loop to which it is attached; rarely, it may undergo incarceration or strangulation, necrosis, and perforation. In children, it is mostly found in umbilical hernias, and the diverticulum is more prone to adhere to the sac. Repair of Littre hernia consists of resection of the diverticulum and herniorraphy; in perforated cases, care must be taken to not contaminate the hernia field.

Littre Hernia: Surgical Anatomy, Embryology, and Technique of Repair:

BACKGROUND: The transversus abdominis plane (TAP) block provides effective postoperative analgesia in adults undergoing major abdominal surgery. Its efficacy in children remains unclear, with no randomized clinical trials in this population. In this study, we evaluated its analgesic efficacy over the first 48 postoperative hours after appendectomy performed through an open abdominal incision, in a randomized, controlled, double-blind clinical trial. METHODS: Forty children undergoing appendectomy were randomized to undergo unilateral TAP block with ropivacaine (n 19) versus placebo (n 21) in addition to standard postoperative analgesia comprising IV morphine analgesia and regular diclofenac and acetaminophen. All patients received a standard general anesthetic, and after induction of anesthesia, a TAP block was performed using the landmark technique with 2.5 mg kg 1 ropivacaine 0.75% or an equal volume (0.3 mL kg 1 ) of saline on the ipsilateral side to the incision. RESULTS: The TAP block with ropivacaine reduced mean (SD) morphine requirements in the first 48 postoperative hours (10.3 12.7 vs 22.3 14.7 mg; P 0.01) compared with placebo block. The TAP block also reduced postoperative visual analog scale pain scores at rest and on movement compared with placebo. Interval morphine consumption was reduced over the first 24 postoperative hours. There were no between-group differences in the incidence of sedation or nausea and vomiting. There were no complications attributable to the TAP block. CONCLUSIONS: Unilateral TAP block, as a component of a multimodal analgesic regimen, provided superior analgesia compared with placebo in the first 48 postoperative hours after appendectomy in children. (Anesth Analg 2010;111:998–1003)

Ipsilateral transversus abdominis plane block provides effective analgesia after appendectomy in children: a randomized controlled trial.

Hernias through the triangle of Petit (TP) are uncommon. The anatomy of the TP is known to be variable, yet quantitative data are scant. The triangle was observed in 80 adult cadavers and its dimensions and surface area were measured. On the basis of surface area we classified the triangles into four types. Type I or small TP, with a surface area of 12 cm2. Finally, Type IV (17.5%) were not triangles. In these, the latissimus dorsi was covered by the external abdominal oblique muscle. We hope these data will help prediction of which patients are at greater risk of herniation through the TP.

C. Kinsela

Papers

The clinical anatomy of the triangle of Petit