Postdural puncture headache and spinal needle design

Clinical bottom line: In order to reduce risk of severe and non-severe headache following spinal anaesthesia, smaller, noncutting needles should be used. Type of needle is not associated with incidence of backache or difficulty with needle use.

Postdural puncture headache and spinal needle design

Postdural puncture headaches are common with spinal anaesthesia, especially among young and obstetric patients. Size and design of needle have been altered in an attempt to reduce this. For example noncutting needles are thought to reduce headache by reducing leakage of cerebrospinal fluid.

Systematic review

Halpern S, Preston R. Postdural puncture headache and spinal needle design. Metaanalyses. Anesthesiology 1994; 81:1376-83.

Date review completed: Dec 1993
Number of trials included: 16
Number of patients: 1873
Comparisons: Noncutting needle vs. cutting needle. Small vs. large needle (same type)
Main outcomes: Headache, severe headache, backache, difficulty or failure using needle.

Inclusion criteria were randomised controlled trials of spinal anaesthesia looking at postdural puncture headache; comparison of two needle sizes; bevel orientation of needle stated as parallel to the dural fibres; quality score at least 0.5 on stated scale of up to 5. Non-randomised trials may have been included.

The reviewer gave odds ratios and incidence data. From these relative benefits and NNTs were calculated.

Findings

Noncutting versus cutting needles

Nine trials compared noncutting with cutting needles (Table 1). Noncutting needles are significantly less likely to cause headaches than cutting needles. For every 27 patients treated, there will be one fewer patient reporting headache if noncutting needles are used (95% confidence interval 17 to 59). There will also be significantly fewer severe headaches.

There was no significant difference with incidence of backache or difficulty/failure in using needle.

Table 1: NNTs for comparisons of non-cutting versus cutting needles

Complication	No. of Comparisons	Noncutting needle complication/total	Cutting needle complication/total	Noncutting needle % complications	Cutting needle % complications	Relative benefit (95% CI)	NNT (95% CI)
Headache	9	26/882	56/838	3.9	9	0.5 (0.3 to 0.7)	27 (17 to 59)
Severe Headache	9	4/882	14/838	1.1	3	0.4 (0.2 to 0.9)	81 (42 to 1100)
Backache	5	102/555	102/512	22	22	0.9 (0.7 to 1.2)	not calculated
Difficulty with Needle Insertion or Failure	5	14/582	23/539	2.8	3.4	0.6 (0.3 to 1.1)	not calculated

Small versus large needles

Eight trials compared a small needle (smaller than 26 gauge) with a larger needle (bigger than 26 gauge) (Table 2). Small needles are significantly less likely to cause headache than large needles. For every 13 patients treated, there will be one fewer patient reporting headache if small needles are used (95% confidence intervals 10 to 19). There will also be significantly fewer severe headaches (one less for every 29 patients treated).

There was no significant difference with incidence of backache or difficulty/failure in using needle.

Table 2: NNTs for comparisons of small versus large needles

Complication	No. of Comparisons	Small needle complication/total	Large needle complication/total	Small needle % complications	Large needle % complications	Relative benefit (95% CI)	NNT (95% CI)
Headache	8	31/910	107/963	3.8	13.6	0.3 (0.2 to 0.5)	13 (10 to 19)
Severe Headache	6	2/725	29/772	0.2	5.3	0.1 (0.1 to 0.4)	29 (20 to 51)
Backache	3	81/476	74/472	13	13	1.1 (0.8 to 1.4)	not calculated
Difficulty with Needle Insertion or Failure	5	11/676	9/721	3	1.4	1.4 (0.6 to 3.0)	not calculated

Postdural puncture headache and spinal needle design