EDITOR:
Ankylosing spondylitis can pose several anaesthetic and obstetric problems during pregnancy. This disease presents a unique scenario of difficult airway and difficult ‘back’. Ankylosing spondylitis is a predominantly axial form of arthritis that usually begins in the sacroiliac joints and slowly progresses to spinal fusion. It presents initially with chronic lower back pain or stiffness. The estimated male to female ratio is between 4 : 1 and 6 : 1 [Reference Gran and Husby1–Reference Gran and Husby3] with HLA-B27 antigen association. As the peak incidence is in the young adult population [Reference Rigby2,Reference Gran and Husby3], pregnancy may occur.
Case report
A 33-yr-old female patient with a 5-yr history of ankylosing spondylitis who was taking sulphasalazine had in vitro fertilization resulting in a twin pregnancy. She had severe spinal involvement with lumbar spondylosis at L4/5, sacroilitis and cervical spine involvement. Sulphasalazine was stopped at 8 weeks of gestation due to risk of kernicterus in the newborn.
Antenatal follow-up was uneventful except that in the second trimester she complained of presyncope and slight breathlessness on walking. Two-dimensional echocardiography showed normal valves and normal left ventricular function. Her symptoms were attributed to physiological pregnancy changes. As there was severe spinal and sacroiliac involvement, mechanical problems with progress of labour and vaginal delivery were expected especially in this parturient with twin pregnancy. Caesarean delivery was planned at 37 weeks of gestation and she was referred to the preanaesthetic clinic at 35 weeks of gestation.
She was 59.2 kg in weight, 161 cm in height, with a body mass index (BMI) of 22.8. She had limited neck flexion of 20 degrees, very limited neck extension, but did not experience neck tenderness. She had a mouth opening of two finger breadths and a Mallampati Grade III airway. Back examination revealed a very stiff lower back, reduced interspinous spaces at L3/4 and L2/3 and a classic ‘bamboo spine’ appearance. She had no neurological complaints or deficits. No cardiac murmur was heard and respiratory examination was unremarkable. She was counselled regarding combined spinal–epidural anaesthesia during her Caesarean delivery with possible conversion to general anaesthesia with awake fibreoptic intubation.
A difficult airway trolley and a fibreoptic bronchoscope were on standby in the operating theatre. No premedication had been administered. An 18-G intravenous cannula was inserted and non-invasive blood pressure (BP), electrocardiography and pulse oximetry monitoring were established. After preloading with 500 mL of crystalloid, a combined spinal–epidural anaesthetic was attempted in the sitting position.
After cleaning, draping and skin infiltration with 1.5% lidocaine, a lateral approach was taken. The first attempt was unsuccessful as there was difficulty advancing the Tuohy needle. On the second attempt the epidural space was identified using loss of resistance to air at 5 cm from the skin. A spinal needle was inserted through the Tuohy needle and heavy bupivacaine 2.0 mL with 100 μg morphine was administered upon visualization of clear free-flowing cerebrospinal fluid. However, there was difficulty with threading the epidural catheter despite injection of saline through the epidural needle and fine adjustment of the Tuohy needle and thus it was abandoned. A T5 level of loss of sensation to cold with a Bromage score of 3 was achieved. BP was maintained with phenylephrine 300 μg in total. She was breathing spontaneously on room air and no desaturation was observed. A senior obstetrician performed the Caesarean delivery. Twin 1 was cephalic and delivered with Wrigley’s forceps. Twin 2 was breech and breech extraction was performed. Both twins had APGAR scores of 9 at 1 min and 5 min. The estimated blood loss was 300 mL.
Postoperatively, she had a pain score of 0 and remained haemodynamically stable in the postoperative anaesthetic care unit. She was able to eat and drink within 6 h postoperatively. She was fully ambulant by postoperative day 1 and was discharged on postoperative day 3. Postoperative anaesthetic review revealed no neurological complications related to the regional technique.
Discussion
Although the anaesthetic management of pregnancy in the presence of ankylosing spondylitis has been described before [Reference Bourlier and Birnbach4–Reference Hiruta, Fukuda, Hiruta, Hirabayashi, Kasuda and Seo6], this is the first case reported in twin pregnancy from in vitro fertilization undergoing Caesarean delivery. Severe postural and joint deformity of ankylosing spondylitis posed interesting challenges to the anaesthetist and there are few published data on care during pregnancy. It involves management of the difficult airway and difficult ‘back’. The physical back deformities result in a high risk of neuraxial block failure [Reference Schelew and Vaghadia7]. In one study involving neuraxial anaesthesia for lower limb surgery, neuraxial access consisted of 13 spinal and three epidural attempts. Spinal anaesthesia was possible in 10 (76.2%) cases and failed in three (23.8%). Epidural anaesthesia was unsuccessful at each attempt. Spinal anaesthesia is therefore advocated for neuraxial anaesthesia in ankylosing spondylitis.
If epidural anaesthesia is required, a paramedian or lateral approach is preferred. In this case, a lateral approach with combined spinal–epidural technique was used and spinal anaesthesia administered. However, there was difficulty in threading the epidural catheter. Methods to assist catheter insertion include paramedian or lateral approach and injection of saline through the epidural needle, to open up the epidural space. Placement of an epidural catheter in the parturient may be technically difficult, as there is calcification of interspinous ligaments, osteophyte formation with fusion of the vertebral column and ankylosis of the lumbar region, which may lead to difficulty threading the epidural catheter. As such, a normal dose of local anaesthetic should be administered because an epidural top-up may not be possible if the epidural catheter cannot be inserted. A sequential combined spinal–epidural technique is not advocated. As neurological complications may be a contraindication to regional anaesthesia, a careful neurological history and examination must be conducted to document any deficits.
General anaesthesia may be required if the neuraxial blockade proves difficult, fails or is inadequate. The difficult intubation trolley and flexible fibreoptic intubating bronchoscope should be available in the operating theatre. Cervical spine ankylosis, temporomandibular ankylosis and cricoarythenoid arthritis may lead to difficult intubation. Loss of normal neck flexion and extension, coupled with osteoporosis, may lead to fracture with minor trauma from airway manipulation. A thorough airway assessment including range of movement of neck, head and cervical spine, and predictors of ease of intubation such as Mallampati scoring should be undertaken.
Successful management of a parturient with ankylosing spondylitis with a difficult airway and difficult ‘back’ is challenging and requires a multidisciplinary approach. It involves the rheumatologist, obstetrician, anaesthetist and neonatologist. Neuraxial anaesthesia can be considered and a lateral approach should be used. A normal dose of spinal local anaesthetic can achieve an adequate level of block, although epidural catheter insertion may be difficult.
