Changing trends in paediatric regional anaesthetic practice in recent years

Clinical anatomy of the maxillary nerve block in pediatric patients

BACKGROUND

Anatomical landmarks in children are mostly extrapolated from studies in adults. Despite this, complex regional anesthetic procedures are frequently performed on pediatric patients. Sophisticated imaging techniques are available but the exact position, course and/or relationships of the structures are best understood with appropriate anatomical dissections. Maxillary nerve blocks are being used for peri-operative analgesia after cleft palate repair in infants. However, the best approach for blocking the maxillary nerve in pediatric patients has yet to be established.

OBJECTIVE

To determine the best approach for blocking the maxillary nerve within the pterygopalatine fossa.

METHODS

In an attempt to define an optimal approach for maxillary nerve block in this age group three approaches were simulated and compared on 10 dried pediatric skulls as well as 30 dissected pediatric cadavers. The needle course, including depth and angles, to block the maxillary nerve, as it exits the skull at the foramen rotundum within the pterygopalatine fossa, was measured and compared. Two groups were studied: Group 1 consisted of skulls and cadavers of neonates (0-28 days after birth) and Group 2 consisted of skulls and cadavers from 28 days to 1 year after birth.

RESULTS

No statistically significant difference (P > 0.05) was found between the left and right side of each skull or cadaver. Only technique B, the suprazygomatic approach from the frontozygomatic angle towards the pterygopalatine fossa, exhibited no statistical significance (P > 0.05) when other measurements made on the skulls and cadavers were compared. Technique A, a suprazygomatic approach from the midpoint on the lateral border of the orbit, as well as technique C, an infrazygomatic approach with an entry at a point on a vertical line extending along the lateral orbit wall, showed statistical significant differences when measurements of the skulls and cadavers were compared.

CONCLUSIONS

On the basis of these findings technique B produces the most consistent data for age groups 1 and 2 and supports the clinical findings recently reported.

A review of the surface and internal anatomy of the caudal canal in children

The anatomy of the sacral hiatus and caudal canal is prone to significant variation, yet studies assessing this in the pediatric population remain limited. Awareness of the possible anatomical variations is critical to the safety and success of caudal epidural blocks, particularly when image guidance is not employed. This systematic review analyzes the available evidence on the clinical anatomy of the caudal canal in pediatric patients, emphasizing surface anatomy and internal anatomical variations. A literature search using three electronic databases and standard pediatric and anatomy reference texts was conducted yielding 24 primary and seven secondary English-language sources. Appreciating that our current landmark-guided approaches to the caudal canal are not well studied in the pediatric population is important for both clinicians and researchers.

Peripheral catheter techniques

With ultrasound, continuous peripheral nerve blocks (CPNBs) are one of the most recent developments in regional anesthesia in children. CPNBs are now used more widely in children because more suitable materials have been marketed, allowing complete, and prolonged postoperative pain control. Their use after orthopedic procedures in children and treatment for complex regional pain syndrome in adolescents has demonstrated the benefits. Perineural catheters have also shown their superiority over other techniques of continuous regional anesthesia in terms of side effects. The efficiency and the safety of these techniques may facilitate early ambulation with improved pain management, treatment at home with disposable pumps, and improved rehabilitation of children. Studies on large cohorts of patients published to date have failed to highlight any severe complications in their use compared with other adult studies. Accidents owing to systemic toxicity are very unlikely if the recommended maximum dose is not exceeded. The safety of continuous regional anesthesia techniques in children relies on the use of low-concentration l-enantiomer solutions (ropivacaine or levobupivacaine) accompanied by low plasma concentrations of local anesthetics, limiting the risk of systemic toxicity of these molecules. CPNB can ensure strong and lasting analgesia in hospital or at home.

Equipment and monitoring--what is in the future to improve safety?

There have been a number of recent developments in the practice of anesthesia and intensive care aimed at improving outcome in terms of reducing both morbidity and mortality, as well as other less-defined factors, such as quality of service provision. Significant advances have been made in airway devices such as pediatric tracheal tube designs, Microcuff(®) tracheal tubes, and new laryngoscopes. Noninvasive monitoring devices, including continuous hemoglobin analysis and near infrared spectrometry, are being increasingly used in pediatric anesthesia. Other, 'scaled-down' versions from adult anesthesia care, however, have not universally been shown to result in improved safety and outcomes in pediatric anesthesia.