4.1 Introduction

Patient positioning and operating room setup are critical steps in ensuring the success and safety of pediatric endoscopic skull base surgery. With recent technological advances in neuroendoscopic surgery, there has been an exponential increase in the skull base surgeon’s armamentarium, with different instrument clusters vying for space and attention in the operating room. Therefore, it is vitally important to optimize operating room setup, patient positioning, and use of navigational technology to ensure a smooth workflow, improve ergonomics, and minimize clutter. This chapter will provide an updated overview of patient positioning and operating room setup specific to pediatric endoscopic skull base surgery.

4.2 Patient Positioning

Patient positioning is a critical component of each surgery, as it determines accessibility to the surgical target, visualization, and any potential harm done to the patient in this process. The patient’s head may be secured using a clamp/pin-based system (▶ Fig. 4.1), which provides rigid fixation, or a mask-based system (▶ Fig. 4.2), which allows for free manipulation of the head during surgery. There are advantages and disadvantages associated with each method that make one more favorable than the other depending on the case.

The Mayfield clamp (three pins) or the Sugita head holder (four to six pins) allows for stabilization of the head by distributing the pressure at multiple pin sites. The more the number of pins used to fix the head, the less pressure on each individual pin site, making a calvarial breach less likely in younger patients. Upon fixation of the head in a certain position, any changes in the position of the head are not feasible during the surgery. This could be a disadvantage if a wide range of maneuvers is required during surgery. Another drawback with rigid-pin fixation in pediatric patients is the increased risk of skull fracture, scalp laceration, or development of a pin-site hematoma. Pin-site epidural hematoma in children has been reported to have an incidence of rate of 0.65%. ¹ Currently, there are no guidelines in place for the application of cranial fixation pins, but it is often avoided in patients younger than 3 years of age. ^{2 ,​ 3}

The major disadvantages of rigid head fixation are addressed in the mask-based system. The patient’s head is placed in a soft headrest (▶ Fig. 4.2a,b), which allows for easy mobility of the head during surgery. This flexibility in head movement allows the surgeon to flex, extend, or rotate the patient’s head to access varying regions of the skull base in an ergonomic fashion. This will be further discussed later in the chapter. A mask-based navigation system (▶ Fig. 4.2c) is placed on the patient’s face/forehead to allow for accurate stereotactic localization of pathology. It is important to note that by not fixating the head, there is increased risk for unwanted head movements during the procedure. Another option for accurate stereotactic localization without cranial fixation is to screw the localization prong directly into the patient’s skull. This, however, might not be an attractive option in younger patients with thin calvariums.

4.2.1 Head Positioning

The head can be positioned in a neutral position, or at different points along the sagittal plane in flexion or extension (▶ Fig. 4.3b), depending on the location of the lesion. Clival lesions require the head to be positioned in a neutral to slightly flexed position. Lesions located within the sella require the head to be positioned in a neutral or slightly extended position. Suprasellar and planum lesions require further extension of the head to about 15° from the neutral position. These variations in inclination of the head according to location of the lesion are necessary to improve ergonomics and facilitate direct access to the lesion. However, since the endoscope itself can be positioned at any angle, the main goal of head positioning is the surgeon’s comfort rather than visualization. If a patient’s head with a planum lesion is pinned neutral or in flexion, a 0-degree endoscope will be positioned too close to the patient’s chest in order to “look up,” interfering with the maneuvering of the surgical instruments. Similarly, if a patient’s head with a clival lesion is pinned in extension, the 0-degree endoscope will be positioned too high above the patient’s chest in order to “look down,” creating an awkward working angle for the surgeon.

Head rotation, which involves moving the head along the axial plane (▶ Fig. 4.3a), and head tilt, in which the head is rotated in the coronal plane (▶ Fig. 4.3c), are other ways to manipulate head positioning. Usually, the head is rotated and tilted 10-15° toward the side where the primary surgeon is standing to improve ergonomics. For right-handed surgeons, the head is rotated and tilted toward the right side and vice versa. Optimal head positioning is paramount in cases where the patient’s head is in rigid pin fixation, because that is the position that the head will remain throughout the case. More importantly, in order to minimize bleeding and reduce venous engorgement, it is important to try to elevate the head above the heart with flexion of the back or reverse Trendelenburg. In order to achieve adequate head elevation, the bed must often be positioned low to the ground.

Related posts:

2 Pediatric Rhinologic Considerations 8 Combined Transcranial and Endonasal Approaches 5 Instrumentation 10 Endonasal versus Supraorbital Eyebrow Approaches: Decision-Making in the Pediatric Population 9 Transorbital and Multiportal Approaches 11 Ventral Approaches to Intraparenchymal Tumors of the Skull Base and Brainstem

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