Potentially disastrous reversal of neuromuscular block agents before removing Mayfield head holder
Precision in all surgical procedures is critical, and it is an undeniable factor. The millimetric accuracy, however, is essential in the majority of neurosurgical cases, especially in functional stereotactic and neuronavigation procedures, where long instruments are placed through the cerebral parenchyma aiming for deep specific encephalic points. Even with an exhaustive study of tractography, for instance, or any other imaging guidance software during surgery, the risk of damaging a “non-silent” central nervous system structure such as the internal capsule is always present and impersonates catastrophic consequences. For that reason, the complete immobilization of the head while performing these procedures is mandatory. One of the most employed devices to provide skull stability, allowing outstanding required precision, is the head holder. The pioneering work of Dr. James Gardner, in his brilliant article published in 1935, displayed a head holder apparatus that became the prototype for the succeeding devices designed later. Currently, the Mayfield device is the most ordinarily employed worldwide. It is fashioned by a three-pin skull clamp that sustains the cranium in a motionless state. Several complications have been reported associated with the misuse of this equipment. The surgeon precipitates the preponderance of them, such as skull fractures and epidural hematomas.
Nevertheless, the surgeon is not the sole blameworthy in this complicated multifactorial equation known as surgical-anesthetic procedure. The misapplication of basic concepts of pharmacology allied to the lack of understanding of the surgical timeline and sequential operational steps could imply harmful outcomes. One of the most common consequences of the sequential misconception above described is the scalp laceration. It occurs while the patient superficializes and without following commands starts moving, usually as a response to the painful stimulus granted by the sharp pins attached to the skull. This uncoordinated movement can result in losing the pins from the skull and ultimately serving as a scalpel that could promote terrifying scalp lacerations. Furthermore, the temptation of early recovery from the deep neuromuscular block status necessary throughout surgery is often described, especially by inexperienced anesthesia providers.
Another significant point that should not be neglected is the unpleasant financial consequences that could accompany this fiasco. Even though patients undergo an awake craniotomy and regain consciousness with pins in place, they face a completely different situation. First of all, surgeons and anesthesiologists have previously scrutinized them who decide if the patient is emotionally able to tolerate this event. Additionally, the patient is informed about the situation, and the scalp block performed for these procedures plays a huge rule in offering more comfort and pain control.
For the reasons addressed before, we strongly suggest that the reversal of the neuromuscular block agent should be done only after the removal of the headholder pins. Concurrently, the authors desire to emphasize that this unfortunate anesthetic complication is entirely preventable, and all efforts must be made to avert patient harm.
1 WJ. Gardner Intracranial Operations in the Sitting Position Ann Surg., 101 (1935), pp. 138-145
2 W.D. Baerts, J.J. de Lange, L.H. Booij, G. Broere Complications of the Mayfield skull clamp Anesthesiology., 61 (1984), pp. 460-461