Achondroplasia

Difficult airway - Midface hypoplasia, a relatively large tongue, a short neck, and limited neck extension make mask ventilation and intubation harder; plan a difficult-airway approach with video laryngoscopy and keep awake or spontaneous-ventilation options in reserve.

Cervical spine and foramen magnum - Foramen magnum stenosis and possible atlantoaxial instability put the brainstem and cord at risk; avoid extremes of neck flexion and extension, keep the neck neutral, and factor this into airway positioning.

Neuraxial is difficult and dose-unpredictable - Short pedicles, spinal canal stenosis, and kyphoscoliosis make placement hard and the required local-anesthetic dose smaller and less predictable; a titrated epidural or a low, incremental technique is usually preferred over a fixed single-shot spinal.

Respiratory - A restrictive chest wall, a small airway, and frequent obstructive sleep apnea predispose to postoperative respiratory compromise; use opioids cautiously and monitor.

Positioning and access - Short limbs make IV and regional access and blood-pressure cuff fit harder; pad and position carefully given joint and spine deformities.

The most common skeletal dysplasia, an autosomal dominant mutation of the fibroblast growth factor receptor 3 (FGFR3) gene that impairs endochondral ossification. It produces disproportionate short stature with rhizomelic (proximal) limb shortening, a large head with frontal bossing, and midface hypoplasia. The anesthetically important features flow from the abnormal bone: foramen magnum stenosis that can compress the brainstem and cervical cord, possible cervical instability, a difficult airway, restrictive lung disease with a high rate of obstructive sleep apnea, and a distorted spine that complicates neuraxial techniques.