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Comment on ‘Practical advice for avoidance of pain associated with insertion of intrauterine contraceptives’: authors’ response

tract may be created where tenaculum teeth penetrated the cervix with the threads then finding their way into the tract before it heals. I would recommend use of less traumatic forceps such as Judd-Allis or Littlewood. 4 I endorse the superiority of tapered (e.g. Bonney Barker type) dilators over shouldered (Hegar type) dilators, but more than this there is a technique for finding the path of least resistance. Careful bimanual examination establishing the position of the fundus relative to the cervix does not allow the inserter to judge the exact direction to angle the dilator when they meet resistance. Straightening the cervico-isthmic junction with traction on the cervix can sometimes be helpful. However gently manipulating a dilator through 360° and sometimes changing the angle quite acutely may find a path with almost no resistance. This is much easier with a scanner at the bedside and a uterus that is sufficiently anteverted for simultaneous ultrasound guidance. Through use of simultaneous ultrasound guidance I have noted that suprapubic pressure can sometimes relax the internal os. On occasions when I have left the sound at the point of resistance while helping the assistant focus the image on the endocervical-endometrial canal we have noted the sound suddenly ‘fall into’ the cavity. I have not tried a suprapubic warming pack but presume that this is likely to have the same or better effect. 5 The os finder is good for stenosis of the external os. I would not recommend its use to overcome stenosis (or spasm) of the internal os. A tapered metal dilator would be my instrument of choice as it enables one to find a path of least resistance when the dilator is gently rotated and angulated at the point of resistance. One cannot do this with the os finder as it is too flexible and too sharp. 6 The authors recommend an intracervical block for difficult sounding. Cochrane Reviews conclude there is inadequate evidence of benefit with local anaesthetic. However, data available on abortion under local anaesthetic supports that deep paracervical injection combined with a relatively high concentration of intrauterine lidocaine infusion improves pain scores. So my own practice where injection is needed is to insert a paracervical block. My understanding of the difference between intracervical and paracervical block is that with the former the needle is introduced through the cervical os and with the latter the needle is introduced a distance of 1– 2 cm lateral to the os, which enables placement of the block at a higher level. I would strongly discourage use of a syringe with a 21 gauge needle, not only because it does not fit down the speculum leaving room for visualisation but because the needle size is too large for comfort. Use of a dental syringe with a long 27 gauge needle is superior. Although one cannot exclude vascular injection by checking for backflow, in practice a slight resistance with injection should confirm placement within tissue.