Anesthetic Management

Impact of genetics on the diagnosis and clinical management of syndromic craniosynostoses

PURPOSE

More than 60 different mutations have been identified to be causal in syndromic forms of craniosynostosis. The majority of these mutations occur in the fibroblast growth factor receptor 2 gene (FGFR2). The clinical management of syndromic craniosynostosis varies based on the particular causal mutation. Additionally, the diagnosis of a patient with syndromic craniosynostosis is based on the clinical presentation, signs, and symptoms. The understanding of the hallmark features of particular syndromic forms of craniosynostosis leads to efficient diagnosis, management, and long-term prognosis of patients with syndromic craniosynostoses.

METHODS

A comprehensive literature review was done with respect to the major forms of syndromic craniosynostosis and additional less common FGFR-related forms of syndromic craniosynostosis. Additionally, information and data gathered from studies performed in our own investigative lab (lab of Dr. Muenke) were further analyzed and reviewed. A literature review was also performed with regard to the genetic workup and diagnosis of patients with craniosynostosis.

RESULTS

Patients with Apert syndrome (craniosynostosis syndrome due to mutations in FGFR2) are most severely affected in terms of intellectual disability, developmental delay, central nervous system anomalies, and limb anomalies. All patients with FGFR-related syndromic craniosynostosis have some degree of hearing loss that requires thorough initial evaluations and subsequent follow-up.

CONCLUSIONS

Patients with syndromic craniosynostosis require management and treatment of issues involving multiple organ systems which span beyond craniosynostosis. Thus, effective care of these patients requires a multidisciplinary approach.

Anesthetic concerns of external maxillary distraction osteogenesis

BACKGROUND

External maxillary distractions present additional anesthetic concerns to the existing complexity of the patient with craniofacial disorder. The distraction hardware is rigidly fixed to the cranium and projects in the frontofacial midline, thus limiting oronasal airway access.

METHODS

A review of 16 patients (10 male, 6 female) having external maxillary distraction was done. Patients with patent tracheostomies were excluded. In all cases, the same type of external distraction device was used (R.E.D., K.L.S. Martin, Jacksonville, FL, USA). Perioperative records were reviewed for medical history; operative diagnosis, presence of airway disease, tracheostomy, laryngoscopy grade, use of fiberoptic bronchoscope, procedure, operative time, use of intraoperative steroid, day of postoperative extubation, and need for reintubation were documented.

RESULTS

The study group was subdivided into two diagnostic categories: those with syndromic craniosynostosis (n = 9) and those with cleft lip/palate (CLP) (n = 7). Patients in the craniosynostotic group had grade 1 laryngoscopy views, with the exception of a single patient with Crouzon syndrome who had a grade 3 view. This was the only patient who required fiberoptic intubation. One patient with Apert syndrome required reintubation (48 hours after surgery); successful extubation was done 96 hours later. In the cleft lip/palate group, all patients had grade 1 laryngoscopic views, except one with a grade 3 view; no patient required fiberoptic intubation. Six of the seven patients were extubated immediately after surgery, with one patient extubated the next day. No patient experienced failure of extubation.

CONCLUSIONS

External maxillary distraction minimally affects anesthetic management provided certain safeguards are observed. The vertical bar can be left attached to the cranial portion of the distractor, or it can be removed for extubation or reintubation. Removal of the vertical bar allows unobstructed direct laryngoscopy. This emphasizes the importance for the emergent availability of the appropriate screwdrivers and wire cutters to remove the vertical bar and trained personnel to perform the removal.

Difficult tracheal intubation induced by maxillary distraction devices in craniosynostosis syndromes

BACKGROUND

Difficult intubation occurred during anaesthesia for removal of maxillary distraction devices in five of seven children with syndromal craniosynostoses (four with Apert, two with Pfeiffer and one with Crouzon syndrome).

METHODS

Intubation was assessed in terms of laryngeal view and an established intubation difficulty score and had been straightforward before device insertion. Difficulty was induced by trismus due to device insertion and by increased maxillary prominence. This was compounded by preexisting mandibular hypoplasia. Cephalometric analysis, with each child acting as their own control, demonstrated anterior displacement of the maxilla and increased maxillary vertical height, as well as increased protuberance of the maxillary incisors.

RESULTS

All five difficult tracheal intubations were associated with preoperative Mallampati scores of 3 or 4 and the nine straightforward intubations with scores of 1 or 2. Maximal interincisor distance was less than the lower 95% confidence limit for age in all five children who were difficult to intubate at the time of device removal. No child had a failed intubation, but all had significantly increased intubation difficulty.

CONCLUSIONS

In view of the risks of trauma, hypoxia and aspiration associated with difficult direct laryngoscopy, we recommend elective fibreoptic intubation at anaesthesia for removal of maxillary distraction osteogenesis devices in these children.

Respiratory complications during anaesthesia in Apert syndrome

BACKGROUND

Clinical experience with anaesthesia for a series of patients with Apert syndrome (craniosynostosis, midface hypoplasia and syndactyly) has not been reported previously.

METHODS

In this review, 10 years of experience was examined at our hospital. There were 145 anaesthetics administered to 18 individuals.

RESULTS

There were 16 complications (15 were perioperative wheezing) which occurred in seven patients. In four cases, surgery was cancelled due to intractable wheezing.

CONCLUSIONS

We could not demonstrate any benefit from preoperative administration of nebulized albuterol. Paediatric anaesthetists should be aware of this high incidence of respiratory complications in Apert syndrome.

Specific genetic diseases at risk for sedation/anesthesia complications

We reviewed of a number of genetic diseases known or at risk for sedation or anesthesia complications. Some of these conditions are relatively common (e.g., Down's syndrome) whereas others are rare or present with multiple congenital anomalies that have an impact on health care delivery. We listed complications, recommended presedation evaluations, and included checklist items to assist the health care provider administering sedation and anesthesia. A better recognition and awareness of risk factors associated with specific genetic diseases should lessen the likelihood of complications during these procedures.

IMPLICATIONS

This article provides a brief description of potential problematic genetic disorders and associated complications that may manifest during sedation or anesthesia. Recommendations for presedation evaluation and checklist items are given that may impact on the delivery of care for these patients.

Difficult tracheal intubation following midface distraction surgery

A case of difficult intubation in a patient with Apert syndrome, who had recently undergone bilateral internal midface distraction, is described. The 14-year-old boy had no antecedent history of such difficulty, despite numerous previous anaesthetics. We suggest that trismus due to temporalis muscle fibrosis, and the altered relationships of the maxilla and mandible following midface advancement, were causal.

Airway management in neuroanaesthesia

PURPOSE

Airway management in neurosurgical patients presents unique challenges to the anaesthetist. This review will consider specific approaches to numerous problems in airway management related to logistical, physiological and anatomical concerns. The goal is to provide a clinically oriented and practical discussion regarding issues of airway management in neurosurgical patients.

SOURCE

The recent literature has been reviewed regarding airway management options and related perioperative complications in the neurosurgical population. This is interlaced with approaches to many of the problems and their solutions based on experience gained in a very busy university neurosurgical practice over the past decade.

PRINCIPAL FINDINGS

Specific pathophysiological alterations in the neurosurgical patient influence the technique chosen for securing an airway. These relate to the presence of increased intracranial pressure, intracranial aneurysms or arteriovenous malformations. Other important disorders influencing airway management include severe coronary artery disease, acromegaly and congenital airway difficulties. Stereotactic neurosurgery and conscious sedation for various neurosurgical procedures also provide unique challenges. There are other considerations unique to the neurosurgical patient such as intra-and postoperative airway obstruction and the timing of postoperative extubation.

CONCLUSION

The demands for airway management in neuroanaesthesia require expertise in the various modes of securing the airway while considering the patient's physiological requirements as well as the unique surgical demands.