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• Arteriovenous malformations and pregnancy
  Dennis R Buis
  Published on: 13 April 2016
• Anaesthetic Considerations
  Catherine T Sheehan
  Published on: 13 April 2016

• Published on: 13 April 2016

  Arteriovenous malformations and pregnancy

  • Dennis R Buis, M.D.
  • Other Contributors:
    • Ellen S Mandl and Harold MP Pelikan

  Dear Editor,

  We read with interest the excellent review by Ng and Kitchen regarding neurosurgery and pregnancy(1). We would like to make two additional remarks. In our opinion the authors failed to address the issue of the pregnant patient with a spinal or dural arteriovenous malformation (sAVM).

  Due to the absence of valves in the epidural venous plexus, the increased intra-abdominal pressure, the additio...

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  Dear Editor,

  We read with interest the excellent review by Ng and Kitchen regarding neurosurgery and pregnancy(1). We would like to make two additional remarks. In our opinion the authors failed to address the issue of the pregnant patient with a spinal or dural arteriovenous malformation (sAVM).

  Due to the absence of valves in the epidural venous plexus, the increased intra-abdominal pressure, the additional stress on the venous circulation during pregnancy and delivery, as well as hormonal changes and increased vascular volume, symptoms of a sAVM may deteriorate severely(2;3). Therefore women with a known sAVM should be informed that pregnancy may worsen their neurological symptoms(3). In women with a myelopathy presenting during pregnancy a sAVM should be ruled out.

  Regarding intracranial AVMs the authors state that the risk of haemorrhage is increased in the second trimester of pregnancy, when cardiac output is at its greatest, however novel data demonstrate that during pregnancy cardiac output is at its greatest in the third trimester and the puerperium(4). Moreover other studies demonstrate an increased incidence of intracranial AVM related haemorrhages in the third trimester and during the puerperium(5).

  References

  1. Ng J, Kitchen N.
  Neurosurgery and pregnancy.
  J Neurol Neurosurg Psychiatry 2008;79:745-52.

  2. Berenstein A, Lasjaunias P, TerBrugge KG.
  Spinal arteriovenous malformations. In: Berenstein A, Lasjaunias P, TerBrugge KG, eds. Surgical neuroangiography 2.2. Clinical and endovascular treatment aspects in adults.
  Berlin: Springer Verlag 2004: 737-847.

  3. Shephard RH.
  Spinal Arteriovenous Malformations and Subarachnoid Haemorrhage.
  British Journal of Neurosurgery 1992;6:5-12.

  4. Trivedi R, Kirkpatrick P.
  Arteriovenous malformations of the cerebral circulation that rupture in pregnancy.
  Journal of Obstetrics and Gynaecology 2003;23:484-9.

  5. Sadasivan B, Malik GM, Lee C, Ausman JI.
  Vascular malformations and pregnancy.
  Surgical Neurology 1990;33:305-13.

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  Conflict of Interest:
  None declared.

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• Published on: 13 April 2016

  Anaesthetic Considerations

  • Catherine T Sheehan, Anaesthetics SpR
  • Other Contributors:
    • Steve Yentis

  Dear Editor

  We read with interest the review of Neurosurgery and pregnancy by Ng and Kitchen.(1) Although reference is made to teamwork including, among others, a neuroanaesthetist, we wish to raise awareness of some specific obstetric anaesthetic issues that may not be familiar to your readers, including some neuroanaesthetists.

  First, general anaesthesia, recommended by Ng and Kitchen for cerebral aneury...

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  Dear Editor

  We read with interest the review of Neurosurgery and pregnancy by Ng and Kitchen.(1) Although reference is made to teamwork including, among others, a neuroanaesthetist, we wish to raise awareness of some specific obstetric anaesthetic issues that may not be familiar to your readers, including some neuroanaesthetists.

  First, general anaesthesia, recommended by Ng and Kitchen for cerebral aneurysms and tumours, has particular risks during pregnancy. There is an approximately tenfold increased risk of difficult or failed tracheal intubation (the latter occurring in ~1:200-300 general anaesthetics),(2) and an increased risk of regurgitation of gastric contents, which combine to make general anaesthesia a major cause of maternal death in past decades (3). Hence, obstetric anaesthetists usually prefer regional (spinal or epidural) anaesthesia whenever possible. Furthermore, the standard technique for reducing these risks during induction of general anaesthesia (the ‘rapid sequence induction’) classically avoids the use of adjuncts that might otherwise be used to reduce the sometimes marked hypertensive response to laryngoscopy and intubation, and the acute increase in intracranial pressure that accompanies it. Although it may be possible to modify or reduce this response, this may risk excessive hypotension which is good for neither mother nor baby. Finally, the use of certain manoeuvres that might reduce intracranial pressure, such as hypoventilation, may be associated with reduced blood flow to the uterus and placenta.

  Conversely, both spinal anaesthesia (in which the dura is intentional punctured with a small (typically 25-27 G) needle) and accidental dural tap during epidural anaesthesia (in which a large (16-18 G) needle is used) are associated with the potential for a CSF leak and post-dural puncture headache, the latter with an overall incidence in obstetric anaesthesia of about 0.5-1%.(4) In the presence of raised intracranial pressure, a CSF leak might lead to coning.(5) Meanwhile, epidural injections themselves may be associated with an increase in intracranial pressure, depending on the speed and volume of injection,(6, 7) and both techniques may be associated with hypotension, occasionally severe (especially spinal anaesthesia).

  The above problems mean that the choice of anaesthetic and analgesic technique must be carefully made after weighing up the risks and benefits in each individual patient. A multi-specialty approach and good communication are of course vital. As obstetric anaesthetists, what we would like to know from our neurological and neurosurgical colleagues are estimations of: (i) how harmful would a sudden large swing in blood pressure, both up and down, be in this patient? (ii) how harmful would an acute increase in intracranial pressure be? (iii) how harmful would a dural puncture be? and (iv) which acute measures, if any, would you suggest if there was a sudden deterioration? This kind of information is crucially important in informing the choice of the obstetric anaesthetist confronted by a patient with neurological disease.

  Catherine Sheehan, SpR Anaesthetist

  Steve Yentis, Consultant Anaesthetist

  References

  1. Ng J, Kitchen N. Neurosurgery and pregnancy. J Neurol Neurosurg Psychiatry 2008; 97: 745-52.

  2. Rahman K, Jenkins JG. Failed tracheal intubation in obstetrics: no more frequent but still managed badly. Anaesthesia 2005; 60: 168-71.

  3. Lewis, G (ed). The Confidential Enquiry into Maternal and Child Health (CEMACH). Saving Mothers’ Lives: reviewing maternal deaths to make motherhood safer 2003-2005. The Seventh Report on Confi dential Enquiries into Maternal Deaths in the United Kingdom. London, CEMACH: 2007.

  4. Paech M, Banks S, Gurrin L. An audit of accidental dural puncture during epidural insertion of a Tuohy needle in obstetric patients. Int J Obstet Anaesth 2001; 10: 162-7.

  5. Su, Thung-Ming; Lan, Chu-Mei MS et al. Brain tumour presenting with fatal herniation following delivery under epidural anaesthesia. Anaesthesiology 2002; 96: 5089.

  6. Grocott H, Mutch W. Epidural anaesthesia and acutely raised ICP: Lumbar epidural space hydrodynamics in a porcine model. Anaesthesiology 1996; 85: 1086-91.

  7. Hilt H, Gramm HJ, Link J. Changes in intracranial pressure associated with extradural anaesthesia. Br J Anaesth 1986; 58: 676-80.

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  Conflict of Interest:
  None declared.

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