Available online at www.sciencedirect.com

Journal of Clinical Neuroscience 15 (2008) 1050–1051
www.elsevier.com/locate/jocn

Case Reports

Brainstem distortion from postoperative cerebellar herniation
through a dural and bony defect
Craig Timms, Nicholas Trost, Yi Yuen Wang, Michael Murphy *
Departments of Neurosurgery and Radiology, St Vincent’s Hospital and Department of Surgery, University of Melbourne, Fitzroy, Victoria 3065, Australia
Received 21 January 2007; accepted 19 June 2007

Abstract
We report a patient with a cerebellar encephalocele following excision of a cerebellar metastasis. This is a life-threatening condition
that may be prevented with adequate dural and bony closure.
Crown Copyright Ó 2007 Published by Elsevier Ltd. All rights reserved.
Keywords: Brainstem distortion; Encephalocele; Cranioplasty

1. Case report
A 48-year-old man with disseminated carcinoma of the
colon presented with headaches and cerebellar signs.
MRI showed a left cerebellar metastasis with significant
surrounding oedema. A posterior fossa craniectomy and
excision of the metastasis was performed. A layer of
SpongostanÒ (Ferrosan, Copenhagen, Denmark) was
placed over the dural defect which was not closed in a
water-tight fashion. The bone flap was not replaced and
a cranioplasty was not performed. Postoperative recovery
was uncomplicated until 4 weeks later when the patient
complained of dizziness and unsteadiness. A postoperative
MRI showed no tumour recurrence or hydrocephalus.
Over the next 3 weeks the patient’s symptoms progressively worsened such that he was unable to lift his head
off the bed without nausea, vomiting and profound vertigo.
A repeat MRI demonstrated herniation of the posterior aspect of the left cerebellar hemisphere through the occipital
craniectomy consistent with an encephalocele. It had become adherent to the overlying nuchal muscles and was
causing traction on the left middle cerebellar peduncle with
associated brainstem distortion. There was no hydrocephalus (Fig. 1). Examination revealed significant brainstem
and cerebellar signs with nystagmus, ataxia and lower cranial nerve deficits. Traction injury and associated oedema
*

Corresponding author. Tel.: +61 3 9288 3341; fax: +61 3 9288 3350.
E-mail address: michael.murphy@svhm.org.au (M. Murphy).

of the underlying cerebellar hemisphere, cranial nerve nuclei and possibly the lower cranial nerves themselves from
repeated posterior occipito-cervical muscle contraction
was the likely pathophysiological aetiology of his signs.
The patient underwent a reduction of the encephalocele,
dural repair and cranioplasty. Within 48 hours his signs
and symptoms had completely resolved. A postoperative
MRI showed repair of the encephalocele with reduction
of the traction on the cerebellar peduncle and cerebellum
(Fig. 2).
2. Discussion
Pain and headache following cranial surgery, particularly posterior fossa surgery has been well described. A
cluster of symptoms was first noted in patients with large
cranial defects by Gardiner in 1945 when he described
the ‘‘syndrome of the trephined”.1 Psychiatric symptoms,
epilepsy, irritability, dizziness, and headaches are all
grouped together in this reported syndrome. The pathophysiology of headache and neurological deficits associated
with cranial defects are suspected to be multifactorial,
including changes in atmospheric pressure, cerebral blood
flow, and cerebrospinal fluid.2 The mechanical motion
of the scalp flap ‘‘sinking” is attributed to gliosis of the
cerebellum and underlying scarring with adherence to the
nuchal musculature.3,4 Attachment to and irritation of
the dura has been thought to result in headache following
posterior fossa surgery.5

Case Reports / Journal of Clinical Neuroscience 15 (2008) 1051–1053

1051

Fig. 1. Axial T2-weighted MRI through the posterior fossa (left) showing herniation of the left cerebellar hemisphere through the occipital craniectomy
and through the supratentorial compartment (right) showing no hydrocephalus.

cation that may occur following cerebellar herniation
through an occipital defect. It should alert readers to the
fact that although there may be no immediate complications associated with not closing the dura or replacing
the bone flap, the uncommon problem described in this paper is serious and potentially life-threatening. Thus, we recommend adequate dural and bony closure for all
intracranial surgery, particularly in the posterior fossa.
We are not aware of a similar report following posterior
fossa surgery.
References

Fig. 2. Post-operative axial T2-weighted MRI showing repair of the
encephalocele with reduction of the traction on the cerebellar hemisphere
and middle peduncle.

A cranioplasty has long been thought to be therapeutic.
This patient confirms this by illustrating a serious compli-

1. Gardiner WJ. Closure of defects of the skull with tantalum. Surg
Gynecol Obstet 1945;80:303–12.
2. Dujovny M, Aviles A, Celso A, et al. Cranioplasty: cosmetic or
therapeutic. Surg Neurol 1997;47:238–41.
3. Stula D. The problem of the ‘‘sinking skin flap syndrome” in
cranioplasty. J Maxillofac Surg 1982;10:142–5.
4. Segal DH, Oppenheim JS, Murovic JA. Neurological recovery after
cranioplasty. Neurosurgery 1994;34:729–31.
5. Santarius T, D’sousa ARD, Zeitoun HM, et al. Audit of headache
following resection of acoustic neuroma using three different techniques
of suboccipital approach. Rev Laryngol Otol Rhino 2000;2:75–8.

doi:10.1016/j.jocn.2007.06.016

Unilateral acute foot drop due to diffuse axonal injury after head trauma
Nail Özdemir a,*, Mustafa Fazıl Gelal b, Serdar Oğuzoğlu a, Mustafa Minoğlu a
a

_
Department of Neurosurgery, Atatürk Training and Research Hospital, Izmir,
Turkey
b
_
Department of Radiology, Atatürk Training and Research Hospital, Izmir,
Turkey
Received 5 February 2007; accepted 3 April 2007

_
Corresponding author. Present address: Çatalkaya M. Pir Sultan Abdal S. No: 42 D:7 35320 Narlıdere-Izmir,
Turkey. Tel.: +90 232 2394146; fax: +90
232 2431530.
E-mail address: nailozdemir@mynet.com (N. Özdemir).
*