This post is an answer to the Case – A Boy With a Droopy Eyelid
There is ptosis (drooping) of the right eye and constriction (myosis) of the right pupil – the condition is termed Horner’s syndrome.
What is the anatomical structure which, when damaged, produces this syndrome?
Either the cervical sympathetic chain itself or, as in this case, the first thoracic sympathetic ganglion, which provides the T1 outflow to the chain.
Why sympathetic damage to the head produces these anomalies ?
The pupil is constricted because of paralysis of the dilator pupillae which is supplied by sympathetic fibres. This leaves intact the constrictor pupillae supplied by the oculomotor (third) cranial nerve. The ptosis is produced by paralysis of the sympathetic fibres, which are transmitted in the oculomotor nerve to supply the levator palpebrae superioris – the elevator of the upper lid.
In the initial phase of this injury, there is also vasodilatation and loss of sweating of the face on the same side, but this is usually transient.
In performing an upper thoracic sympathectomy, the surgeon makes every effort to preserve the T1 ganglion, whose fibres supply the head and neck. The aim is to interrupt the outflow from T2 and T3, which supply the upper limb. In this case T1 was inadvertently injured. Today, this operation is usually performed endoscopically using a thoracoscope. This provides brilliant visualization of the anatomy and reduces still further the risk of T1 injury.
Other quite common causes of Horner’s syndrome
It may be seen in tumour invasion of the cervical sympathetic chain, for example from a Pancoast tumour at the lung apex, secondary deposits in the cervical lymph nodes or from invasion by a poorly differentiated thyroid carcinoma. A severe injury of the roots of the brachial plexus may tear the cervical chain at its rami communicantes.
What effect will cervical sympathectomy have on the patient’s feet?
There will be a compensatory increase in sweating in the feet. The patient should be warned of this prior to surgery.
