Abstract
Bimaxillary osteotomy is a surgical procedure used to correct dentofacial deformity. Although the complication rates are low, there are some rare but serious complications of this procedure.
References
A case report of horner's syndrome presenting post bimaxillary osteotomy
From Volume 45, Issue 2, February 2018 | Pages 164-170
Article
Horner's syndrome develops as a result of disruption of the sympathetic nerve supply to the eye. This article will give an overview of the anatomy of the sympathetic nerve supply to the eye, its pathway and relations. An understanding of the anatomy helps to explain the clinical manifestations and multiple aetiologies of Horner's syndrome, which are described.
Anatomy of the sympathetic innervation of the eye2 (Figure 1)
The sympathetic neurones supplying the eye have their origins in the hypothalamus. After they leave the hypothalamus they take a lengthy and convoluted pathway to the effector organs of the eye. Disruption of the nerve supply can occur at any point along the route, resulting in Horner's syndrome.
The first-order sympathetic neurones supplying the eye leave the hypothalamus, descend in the spinal cord and terminate at the level of C8-T2. Second-order pre-ganglionic fibres exit the spinal cord at T1 and enter the cervical sympathetic chain, where they are closely related to the pulmonary apex and subclavian artery. The fibres ascend through the sympathetic chain and synapse at the superior cervical ganglion at the level of C3-C4 and at the bifurcation of the common carotid artery. The third-order, post-ganglionic sympathetic fibres, responsible for pupil dilation, ascend with the internal carotid artery in the internal carotid nerve. This nerve forms a plexus alongside the internal carotid artery and passes with the artery through the carotid canal to enter the cranial cavity. They enter the cavernous sinus, located at the base of the skull in the middle cranial fossa. While passing through the cavernous sinus, the plexus gives off branches to the oculomotor and ophthalmic division of the trigeminal nerves, which also run through the cavernous sinus. These nerves run anteriorly close to the base of the skull in the middle cranial fossa and enter the orbit through the superior orbital fissure. The ophthalmic division of the trigeminal nerve branches into the nasociliary and long ciliary nerves, which supply the dilator pupillary muscle. The oculomotor nerve supplies the smooth muscle of the levator palpebrae superioris.
Some post-ganglionic sympathetic fibres, arising from the superior cervical ganglion, ascend at the bifurcation of the common carotid. Together with the external carotid artery, these fibres supply the sweat glands and blood vessels of the face.
Clinical signs of Horner's syndrome
The following clinical signs are characteristic of Horner's syndrome:
The presence of this latter sign is variable and dependent on the level of the lesion. It is usually absent from post-ganglionic lesions.
Case report
A 19-year-old male had a bimaxillary osteotomy procedure with maxillary advancement and asymmetric setback of his mandible to correct his skeletal Class III malocclusion. The operation was uneventful and the patient was discharged two days post-operatively.
Following routine review one week post-operatively, the patient noted drooping of his left upper eyelid (ptosis) and sunken ipsilateral eye globe (enophthalmos) with constricted pupil (miosis) (Figure 2).
The patient was referred to the ophthalmology department for review with a working diagnosis of Horner's syndrome and a head CT scan was arranged.
The ophthalmology team noted that the patient was complaining of a droopy left eye but with no other visual complaints, the palpebral being 10 mm in the right eye and 9 mm in the left eye with full eye movements. No diplopia was noted along with no relative afferent pupil defect. He had full colour vision with equal and reactive pupils of 4 mm. The unaided visual acuity was 6/5–2 to both eyes, with a suspicion of early traumatic Horner's syndrome. A head CT scan showed no base of skull fracture and no abnormality within the brain.
Review three weeks post-operatively showed no change in the left eye (Figure 3) and the patient had his fixed appliances removed three months post-surgery, with no resolution of the suspected Horner's syndrome at that stage. On review with the ophthalmology team four months post-operatively, the patient noted a slight improvement in the drooping of his left eye, with both the 5th and 6th cranial nerves assessed as being intact. The ophthalmology team arranged a head, neck and chest MRI and further review was arranged, along with review by the vascular team.
The MRI report noted no abnormality seen in the brain or brain stem, with no abnormality seen in the neck.
On review within the maxillofacial department six months post-operatively, there was some resolution of the drooping of the left eye and partial improvement of pupillary miosis (Figure 4). At this stage, no known cause for the Horner's syndrome had been identified and the patient is currently under long-term review by both the ophthalmology team and the maxillofacial team but, hopefully, further spontaneous resolution will occur.
The aetiology of Horner's syndrome
Horner's syndrome is a rare condition and it can be congenital, acquired or hereditary (autosomal dominant). It may involve first-, second- or third-order neurons, as shown in the list of aetiology in Table 1. Horner's syndrome is an uncommon complication of invasive medical procedures, however, there are documented cases of it developing as a result of a wide variety of surgical procedures. The condition can be temporary or remain permanent. The surgical procedures which are known to have the potential to cause Horner's syndrome include:
| Aetiology of First-order Neurone Lesions | Basal meningitis, eg syphilis |
| Basal skull tumours | |
| Basal skull fracture3 | |
| Cerebral vascular accident | |
| Demyelinating disease, eg multiple sclerosis | |
| Lesions in the hypothalamus or medulla | |
| Neck trauma, eg traumatic dislocation of the cervical vertebrae or traumatic dissection of the vertebral artery | |
| Pituitary tumour | |
| Aetiology of Second-order Neurone Lesions | Birth trauma and injury to the brachial plexus |
| Lung cancer | |
| Cervical rib | |
| Aneurysm or dissection of the aorta | |
| Lesions of the subclavian or common carotid artery | |
| Central venous catheterization | |
| Trauma or surgical injury, eg neck dissection, thyroidectomy, carotid angiography, radio frequency tonsil ablation,5 chiropractic manipulation4 | |
| Chest tubes6,7,8 | |
| Lymphadenopathy, eg Hodgkins lymphoma, leukaemia, tuberculosis, mediastinal tumours | |
| Mandibular tooth abscess | |
| Lesions of the middle ear, eg acute otitis media | |
| Aetiology of Third-order Neurone Lesions | Internal carotid artery dissection9 |
| Raeder syndrome | |
| Carotid cavernous fistula | |
| Cluster or migraine headache | |
| Herpes zoster |
Recognized complications of Orthognathic surgery
There are many recognized complications of orthognathic surgery (Table 2).
| Dental Complications (Common) | Root resorption |
| Loss of tooth vitality | |
| Periodontal defects | |
| Loss of teeth | |
| Common Surgical Complications (usually temporary) | Bleeding |
| Swelling | |
| Parasthesia of the skin and mucosa | |
| Trismus | |
| Sinusitis | |
| Rare Surgical Complications | Infection |
| Haemorrhage | |
| Dental Complications (Rare) | Anaesthesia of skin and buccal mucosa |
| Aseptic necrosis | |
| Unfavourable fractures, eg basal skull17 | |
| Fistula formation | |
| Maxillary instability/fibrous union | |
| Ophthalmic complications – blindness, reduced visual acuity, extra-ocular muscle dysfunction, lachrymal apparatus problems18 | |
| Arteriovenous fistula formation19 |
Serious complications are uncommon1 and the development of Horner's syndrome post orthognathic surgery has not been previously recorded in the literature. However, there is evidence of patients who experienced other ophthalmic complications.18 These included blindness, reduced visual acuity, extra ocular muscle dysfunction and lachrymal apparatus issues. When considering the innervation of the eye it may be possible that some of these complications have a similar aetiology. Base of the skull fractures in maxillofacial trauma are known to have caused Horner's syndrome,3 and unfavourable fractures can occur as a complication of orthognathic surgery,17 which also suggests a causal link.
Summary
Following a literature search for this case history it appears that the development of Horner's syndrome following orthognathic surgery is rare. It is, however, a serious and disfiguring complication and it is important that clinicians are aware that its occurrence is possible in order to initiate its appropriate management. As has been seen in this case, the aetiology of Horner's syndrome post-osteotomy has not been identified and, although Horner's syndrome is not always treatable, prompt recognition and appropriate management is essential.20 Therefore, it would seem prudent to include assessment for Horner's syndrome at post-operative review, along with the usual checks for paraesthesia, etc.
Where the aetiology of Horner's syndrome in a patient is unknown or doubtful, further investigation or referral should be considered. It may be necessary for the patient to undergo head CT, chest x-ray and MRI scans to establish the aetiology, which will ensure that the treatment given is appropriate or a referral to another specialist team is made.
Finally, the development of Horner's syndrome in this particular case has implications concerning informed consent. On the 11 March 2015, the Supreme Court published its judgment in the case of Montgomery vs Lanarkshire Health Board. The case is relevant to all clinicians involved in discussions with patients regarding informed consent. The conclusions were that a patient should be given any material risks associated with treatment that would be important and pertinent to that patient in making a decision regarding his/her treatment; most importantly, this is irrespective of the level of risk. In light of this, particularly since orthognathic treatment is an elective procedure, it could be suggested that clinicians may consider informing their patients about the potential risk of developing Horner's syndrome following orthognathic surgery, even though the definitive aetiology of the Horner's syndrome in this case, following the bimaxillary procedure, had not been identified.