Introduction
Children who are undergoing neurosurgical procedures can benefit from regional anesthesia, which provides excellent analgesia with minimal adverse effects. Peripheral nerve blocks can blunt the surgical stress response, decrease anesthetic requirements, and minimize opioid-related side effects.
Most peripheral nerve blocks of the head and neck are simple to perform since anatomical landmarks are easily located. These blocks can facilitate a significant reduction in both analgesic requirements and the incidence of nausea, vomiting, pruritis, and respiratory depression.1 The nerves undergoing blockade are terminal sensory branches, which can be effectively blocked with minimal volume of local anesthetic solution (Table 6.1). This decreases the likelihood of approaching toxic plasma levels, even in infants and neonates.2
Table 6.1 Head and Neck Blocks for Pediatric Neurosurgical Procedures
| Nerve to Be Blocked | Neurosurgical Indications | Potential Complications |
|---|---|---|
| Trigeminal V1: Ophthalmic division | Frontal craniotomy Ventriculoperitoneal shunt Ommaya reservoir placement Scalp lesions | Hematoma formation Intravascular injection |
| Trigeminal V2: Maxillary division (infraorbital nerve) | Transsphenoidal hypophysectomy | Hematoma formation Persistent paresthesia of upper lip Damage to globe of the eye Intravascular injection |
| Trigeminal V3: Mandibular division (auriculotemporal nerve) | Craniotomy with temporal incisions | Hematoma formation Intravascular injection |
| Greater occipital nerve | Posterior fossa craniotomy Ventriculoperitoneal shunt Occipital craniotomy Occipital neuralgia | Intravascular injection Hematoma formation |
Increased use of regional anesthesia has significantly improved the scope of pediatric pain management.3 Regional anesthetic techniques are often combined with general anesthesia to provide a synergistic multimodal approach to analgesia while maintaining hemodynamic stability. Suresh and Bellig reported a critically ill 700-g neonate who underwent Ommaya reservoir placement for hydrocephalus with adjunctive blockade of both the supraorbital and greater occipital nerves.4 This approach provided good analgesia while minimizing opioid requirements. In the adult literature, blockade of the scalp innervation, which anesthetizes both the superficial and deep layers of the scalp, is considered an effective means to decrease hemodynamic responses to Mayfield head-holder application.5 Nguyen and colleagues conducted a prospective, double-blinded, randomized controlled study to assess the role of scalp blocks in reducing postoperative pain after craniotomy.6 They demonstrated that intraoperative scalp block decreases the severity of pain after craniotomy and that this effect is long lasting, possibly through a preemptive mechanism. Sebeo described the use of peripheral nerve blocks of the scalp in children as a means to provide effective analgesia while maintaining stable hemodynamics.7
Sole regional anesthetic techniques have also been described in the pediatric neurosurgical literature. Uejima and Suresh reported three ex-premature infants who underwent successful placement of ventricular drainage devices using regional anesthesia alone.8 The supraorbital nerve (trigeminal V1) and the zygomaticotemporal nerve (trigeminal V2) were designated as the sensory supply for the surgical operative site and blockade was performed with local anesthetic. All infants were swaddled in a blanket and were allowed to suck on a pacifier dipped in an oral glucose solution during the procedure. No patient required supplemental analgesics or sedative/hypnotic drugs. Sole regional anesthetic approaches may reduce the risk for postoperative apnea in neonates who may otherwise require postoperative ventilation after such procedures.9 Batra and Rajeev have also described the successful use of peripheral nerve blocks as a sole anesthetic to perform burr hole drainage of a brain abscess in a medically complex child who was at an elevated risk for anesthetic complications.10
Safety of Head and Neck Blocks in Children
Peripheral nerve blocks of the head and neck are associated with a low incidence of adverse effects. In contrast to adult practice, most regional anesthetic techniques in children are performed under deep sedation or general anesthesia. Prospective and retrospective safety studies support this practice.11 The Pediatric Regional Anesthesia Network (PRAN) is a multicenter collaborative effort that has facilitated the collection of detailed prospective data for research and quality improvement. Polaner and colleagues recently reported on the first three years of data registry, giving a favorable impression of the safety of current pediatric regional anesthesia practice with no reported complications or adverse events associated with head and neck blocks.12
Clinical Anatomy of the Head and Neck
The sensory supply of the head and neck is primarily derived from three major branches of the trigeminal nerve (cranial nerve V) along with the C2–C4 cervical roots, which supply the neck and the occipital portion of the scalp (Figure 6.1).
Figure 6.1. Cutaneous innervation of the head and neck.
Trigeminal Nerve
The sensory and motor roots of the trigeminal nerve arise from the ventral aspect of the base of the pons. Sensory branches are sent to the large semilunar ganglion, which gives rise to three main divisions: V1 (ophthalmic), V2 (maxillary), and V3 (mandibular). These three major divisions of the trigeminal nerve exit the cranium through three distinct foramina.
V1
The ophthalmic division of the trigeminal nerve provides sensory innervation to the scalp, forehead, upper eyelid, cornea of the eye, mucous membranes of the nasal cavity, the frontal sinuses, and parts of the meninges. The nerve enters the orbit through the superior orbital fissure, where it divides into three branches: (1) frontal (supraorbital n. and supratrochlear n.), (2) lacrimal, and (3) nasociliary.
V2
The mandibular nerve passes through the foramen rotundum and, after exiting the skull, courses anteriorly over the pterygopalatine fossa. The nerve enters the floor of the orbit and emerges through the infraorbital fissure as the infraorbital nerve. The infraorbital nerve carries sensory input from the lower eyelid, the upper lip, teeth, and gums, the nasal mucosa, the palate and roof of the mouth, the maxillary, ethmoid, and sphenoid sinuses, and parts of the meninges. Anatomical localization of the infraorbital nerve has gained recent attention in response to increasing indications for postoperative pain control. Bosenberg and Kimble examined 15 neonatal cadavers and applied their measurements to guiding successful blockade of the infraorbital nerve in four neonates undergoing cleft lip repair.13 Suresh and colleagues evaluated computed tomography (CT) scans of 48 pediatric patients and demonstrated a linear correlation between age and the distance to the infraorbital foramen.14 A mathematical formula (distance to infraorbital foramen from midline = 21 mm + 0.5 × age in years) can be utilized to locate the nerve in cases where palpation of the foramen is difficult.
V3
The mandibular nerve travels into the infratemporal fossa through the foramen ovale and divides into three major branches: (1) auriculotemporal nerve, (2) lingual nerve, and (3) inferior alveolar nerve. The auriculotemporal nerve provides sensory innervation to the external acoustic meatus and auricle of the ear, the temporomandibular joint, and the scalp over the temple.
The terminal branches of the three trigeminal nerve divisions, the supraorbital, infraorbital, and mental nerves, exit the skull through the supraorbital, infraorbital, and mental foramina, respectively, and typically lie vertically in line with each other in the plane of the pupil.
Occipital Nerves
The posterior scalp is innervated by sensory fibers of the greater and lesser occipital nerves.
Greater Occipital Nerve
The greater occipital nerve originates from the posterior ramus of the second cervical spinal nerve (C2) and travels in a cranial direction, medial to the occipital artery, until it pierces the posterior cervical aponeurosis and provides branches medially to supply the posterior portion of the scalp (sensory) and the semispinalis capitis muscle (motor).
Lesser Occipital Nerve
The lesser occipital nerve is derived from the second (and occasionally also the third) anterior cervical ramus and traverses cephalad from the posterior edge of the sternocleidomastoid muscle. At this point, it pierces the deep fascia and travels up the scalp behind the auricle before it divides into several sensory branches.
The following section provides an overview of commonly performed regional anesthetic techniques for pediatric neurosurgical procedures. We describe the indications, landmarks and surface anatomy, technique, and potential complications of relevant head and neck blocks.
Related posts:
Chapter 1 – Developmental Approach to the Pediatric Neurosurgical Patient
Chapter 4 – Neuropharmacology
Chapter 10 – Anesthesia for Fetal Neurosurgery
Chapter 12 – Anesthesia for Cerebrovascular Disease in Children
Chapter 21 – Intensive Care Considerations of Pediatric Neurosurgery
Chapter 20 – Perioperative Salt and Water in Pediatric Neurocritical Care
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