In some cases a spinal anaesthetic will be chosen rather than an epidural because it is quicker to insert and will be fully effective more rapidly (5 to 10 minutes compared to 20 to 30 minutes). A spinal is also technically easier to insert and therefore less likely to be unsuccessful than an epidural.
A spinal may be chosen if the woman needs pain relief for a procedure that needs to be performed relatively quickly. Situations that could lead to a spinal being inserted include if the woman needs to have a
forceps delivery or a
manual removal of the placenta or if
forceps are being attempted in the operating theatre and a Caesarean is possible if the
forceps are unsuccessful. It could also be considered with an
internal podalic version of a second twin being born vaginally. You can read more on this in
twins or more.
In some of these cases the use of a spinal is the preferred option to a
general anaesthetic, because it has less side effects for the mother and the baby or it makes the procedure safer to perform (such as a forceps delivery). If an epidural were already in place then a spinal would not be necessary because the epidural would simply be 'topped up' for the procedure.
More recently, spinal analgesia has also been used in uncomplicated labours (usually in small doses). This may be combined with an epidural, as the spinal aims to provide rapid pain relief in the interim period until the epidural takes effect. It may also be used for women near the end of their labours to provide rapid pain relief if it is their second or subsequent baby and the epidural is considered to take too long to be fully effective.
Statistics for the use of spinals Australia wide are not published. The NSW Department of health publishes statistics on the use of spinals. The combined rates for spinals for labour and / or Caesareans for 2000 range from about 0.3% to 20.5%, depending on the hospital.