There are several commercially available trocar types including the MiniSite system by Covidien, the 3-mm minilaparoscopy set from Storz, the Aesculap Reusable Trocar System, and the Passport trocars from Stryker. The important tenants are safe insertion and ease of instrument exchange. Some trocars, like the MiniSite system , are inserted with a spring-loaded, blunt stylet (Fig. 2.3) or contain a metal conical tipped trocar like the Storz system. Each patient and case is unique; the trocar location and selection are specific to the size of the patient, the instruments being used, and the discretion of the surgeon [8]. Trocar sizes have been a challenge from the onset of minimally invasive surgery in pediatrics. The decrease from 5- and 10-mm instrumentation to 2- and 3-mm instrumentation has greatly aided surgeons in the complicated procedures of their smaller patients. Procedures became feasible in the littlest of children. In general, incisions and trocars are between 2 and 4 mm for neonates. Incisions less than 2 mm heal well without visible scarring. With trocars smaller than 4 mm, a red catheter sleeve can be fit around the outside of the trocar to help stabilize the trocar. The catheter sleeve can then be sutured to the skin thus allowing the trocar mobility without slippage [7]. An example is the two-piece sealing cap that fits at the end of the cannula of Aesculap trocars to preserve the pneumoperitoneum and prevent inadvertent removal when sutured to the abdominal wall. For the more traditional system, the Storz system contains silicone leaflet valves to maintain pneumoperitoneum.

The most common injuries from trocars include bleeding, hernias, bowel injuries, and bladder injuries [9]. The abdominal wall of neonates is relatively thin which allows for slippage of the trocars when instruments are placed through them [10]. Trocar instability can cause a gamut of complications, including air leakage, loss of vision, instrument clashing, and others [11]. Rothenberg reports a specific complication directly related to the laparoscopic approach during one of his procedures: the “injury was a bladder wall injury secondary to the replacement of a 3 mm trocar in the suprapubic position after it had slipped out. The injury was extraperitoneal and was managed by Foley catheter drainage for 5 days” [10]. Jayaram et al. describe an efficient way to prevent complications from trocar instability with the use of a 16- or 18-Fr Foley catheter sleeve over the trocar, in which the sleeve is then fixed to the skin with a stitch [11]. In addition, major vascular injury can occur with trocar insertion including iliac, caval, and umbilical vein injury [12].

Smaller and more versatile instruments have greatly expanded the laparoscopic capabilities in neonates. Figure 2.4 demonstrates the comparison between 3- and 5-mm instruments. A reliable and versatile set of reusable instruments for pediatric laparoscopy is essential for success. The 3-mm minilaparoscopy system by Storz has a set with 36-cm-long instruments that include graspers, dissectors, scissors, cautery, suction, and needle holders for intracorporeal suturing (Fig. 2.5). The major advantage of this set is that it is the only 3-mm set that offers a 36-cm length which is helpful for pediatric patients with thicker abdominal walls. In addition Storz offers this set in 20- and 30-cm lengths. Other brands include Stryker which offers 3-mm instruments and Sovereign^® mini-instruments (Aesculap, Center Valley, PA) which makes 3.5-mm instruments. Finally the MiniSite™ system makes 2-mm instruments that can be used directly through the abdominal wall or through a specially designed part [13].

Carbon dioxide (CO₂ ) insufflation in the pediatric population can result in hypercarbia secondary to CO₂ absorption, changes in respiratory function, and cardiac output and acidosis [17]. Hypercarbia and increased intra-abdominal pressures can cause increased intracranial pressures and cerebral hemorrhage. Cardiovascular parameters are also affected during laparoscopic surgery. At baseline, infants and neonates have a relatively higher cardiac index and oxygen consumption than adults. The mean arterial pressure is lower, and the central venous pressure is comparable [18]. Cardiac output decreases when intra-abdominal pressure exceeds 20 mmHg and when blood flow to the heart is obstructed via compression of the inferior vena cava from cardiac compression to reduction in end-diastolic volume, respectively. Increased intra-abdominal pressures above 10 mmHg can compromise venous return due to compression of the inferior vena cava thus causing hypotension [19]. Systemic vascular resistance is increased due to compression of the aorta and increase in splanchnic arteriolar vasoconstriction from an increased intra-abdominal pressure [16]. Neonates are especially sensitive to absorption of CO₂, causing hypercapnia and hypoxia, and can develop respiratory acidosis.

The main physiological changes upon insufflation are an increase in end-tidal CO₂ and an elevation in peak airway pressures which can be compensated for with slight hyperventilation. Intraoperative minute ventilation should be increased to maintain normocapnia [20], and care should be taken to monitor the neonates that are at risk postoperatively of not being able to maintain increased respiratory rate to blow off the remaining CO₂ [7]. Patients should be monitored with electrocardiogram, pulse oximeter, and end-tidal CO₂ monitor, because at pressure 12–14 mmHg, liver and kidney perfusion is decreased. The insufflation pressure should be set at the lowest possible pressure giving the best possible exposure without causing harm [20].