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CASE REPORT
Year : 2022 | Volume
: 12
| Issue : 2 | Page : 167-169
Combined spinal-epidural for emergency cesarean section in a multiparous parturient with achondroplasia
Siyu Lye1, Phui Sze Au Yong2
1 Division of Anesthesiology and Perioperative Medicine Singapore General Hospital, Singapore
2 Hospital Drive, Singapore
Correspondence Address:
Siyu Lye
KK Women's and Children's Hospital, 100 Bukit Timah Rd, 229899
Singapore
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/JOACC.JOACC_109_21
Parturients with achondroplasia post unique challenges to the anesthetist. Term achondroplastic parturients may have cephalopelvic disproportion resulting in lower section cesarean section (LSCS). Premature ossification of bones results in characteristic craniofacial abnormalities and is associated with atlantoaxial instability and macroglossia leading to a difficult airway. With pregnancy, airway edema and reduced functional reserve capacity further complicate intubation. Central neuraxial blockade (CNB) is challenging due to potential kyphoscoliosis, spinal stenosis, the unpredictable spread of local anesthetics in central neural space, and uncertainty of dose due to disproportionate spinal column to overall height. We present the challenges in a multiparous achondroplastic parturient coming in for emergency cesarean section done under combined spinal-epidural anesthesia technique.
Keywords: Achondroplasia, central neuraxial blockade, combined spinal-epidural, lower section cesarean section, obstetrics, regional
Achondroplasia is the most common form of dwarfism, and this autosomal dominant genetic disorder occurs in approximately 1 in 20,000–30,000 live births.[1] This mutation in the fibroblast growth factor receptor 3 (FGFR3) gene accounts for 20% of occurrence, the remaining 80% due to spontaneous genetic mutation.[1] Term achondroplastic parturients likely have cephalopelvic disproportion (CPD) resulting in lower section cesarean section (LSCS). Both general anesthesia (GA) and central neuraxial blockade (CNB) have unique struggles due to anatomical abnormalities in achondroplasia. Furthermore, the physiological changes of pregnancy add complexity to their management.
We report and discuss the anesthetic management of a multiparous patient with achondroplasia coming in for emergency LSCS done under combined spinal epidural (CSE) technique.
Case HistoryA 33-year-old, gravida 3 para 2, a lady with achondroplasia (height 126 cm, weight 44 kg) presented for emergency LSCS due to prolonged prelabor rupture of membranes (PPROM). Besides achondroplasia, she has no other past medical history.
She was 36 weeks gestation and had two previous LSCS for CPD under general anesthesia (GA) and spinal anesthesia, respectively. She was unbooked and unfasted. A fetal scan done on admission revealed a healthy male fetus with normal cardiotocography tracing. As she had PPROM and was in labor, an emergency LSCS was offered.
On examination, she had disproportionately short limbs and normal spinal column height. Airway assessment showed a potentially difficult airway with Mallampati 3 score, mouth opening of 2.5 fingers breadth, macroglossia, and a receding chin. She had significant lumbar hyperlordosis but no radiculopathy.
Her previous anesthetic chart showed that her LSCS was challenging and took 120 min due to dense adhesions. A single shot spinal anesthetic with 2.1 mL of 0.5% heavy bupivacaine and 15 mcg fentanyl resulted in severe hypotension, requiring a total of 1 g phenylephrine (given in small boluses) over 60 min. Thirty minutes into the surgery, her receding block required supplementation with intravenous analgesia and nitrous oxide.
After thorough discussion and counseling, the patient agreed to central neuraxial block (CNB) for this LSCS. A combined spinal epidural (CSE) was planned to allow fast onset in her emergency setting and careful titration of her block level to avoid excessive high blockade level. Furthermore, this surgery could potentially be complicated and prolonged again.
She was positioned in a sitting position with standard American society of anesthesiologists (ASA) monitors applied. Two attempts at combined spinal-epidural (CSE) were done at the L3/4 intervertebral space. A total of 1.5 mL of 0.5% hyperbaric bupivacaine and 15 mcg fentanyl ere were administered intrathecally. After negative aspiration for blood and cerebrospinal fluid, an epidural catheter of 5 cm was left in situ.
A sensory block height of T2 and complete motor blockade were achieved before skin incision. A total of 700 mcg phenylephrine was required to maintain mean arterial pressure within 20% of the baseline. After 21 min, a healthy 2,870 g neonate was delivered with an Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) score of 8 and 9 at 1 and 5 min, respectively. Thirty five minutes into the surgery, she required epidural top up with 13 mL of 2% lignocaine in titrated boluses and IV ketamine 20 mg due to discomfort. Estimated blood loss was 700 mL. The surgery ended uneventfully after 100 min. At the end of the surgery, her epidural catheter was removed with tip intact, and her postoperative recovery was unremarkable.
DiscussionDue to premature ossification of bones in achondroplastic patients, they present unique challenges in airway management and CNB. In the literature, there is no recommendation on which is the ideal anesthetic method described for LSCS in achondroplastic patients.
General anesthesia may be challenging due to difficult mask ventilation and intubation. A large forehead, short maxilla, large mandible, and macroglossia could cause difficult mask ventilation.[1] A higher prevalence of obesity and obstructive sleep apnea (OSA) in this population can contribute to upper airway obstruction.[2] If severe, can lead to cor pulmonale and pulmonary hypertension. Macroglossia, narrowed oropharyngeal airway, and atlantoaxial instability may hinder intubation.[1] Perovic et al.[3] found that out of 29 dwarfs with congenital dysplasia of the odontoid process, 75% have atlantoaxial instability and 51% have clinical myelopathy. Hence, neck immobilization is recommended for intubation. Reduced endotracheal tube size may be required due to narrow nasal passages and small trachea. Moreover, pregnancy significantly increases soft-tissue edema and friability. Reduced apnea time due to increased oxygen consumption and reduced functional residual capacity (FRC) from pregnancy could further complicate airway management.[4]
Central neuraxial blockade (CNB) can be difficult in achondroplastic parturients. Intervertebral spaces are less palpable due to kyphoscoliosis, worsened by tissue edema and weight gained from pregnancy.[4] They may have prior spinal surgery and instrumentation. Lumbar hyperlordosis and narrowed epidural space increase CNB failure and engorged epidural vessels from pregnancy can lead to a traumatic CNB attempt. Due to vertebral anatomical abnormalities, they are predisposed to spinal canal stenosis and unpredictable spread of local anesthetics.[5]
There is no consensus on the doses of spinal blockade for parturients with achondroplasia. We recommend a combined spinal–epidural technique (CSE) technique to allow the fast and dense onset of subarachnoid block required in emergency surgery. The epidural component allows flexibility and titration of block height to avoid hypotension. This is especially crucial in parturients as fetal circulation is directly dependent on maternal blood pressure.[4] Also, a longer operation time can be facilitated in unexpected circumstances. In our patient, dense adhesions from multiple previous LSCS extended operation time. Limitations include the time required to ensure proper placement of CSE which may not be feasible in emergency LSCS. Real-time ultrasound has also been described to identify intervertebral spaces and depth to increase success in CNB attempts.[6]
In conclusion, both GA and CNB post challenges in achondroplastic parturients to the anesthetist. An early anesthetic evaluation allows discussion, risk counseling, and thorough assessment to plan for the most appropriate anesthesia. We recommend a CSE technique to allow a fast, dense onset of low dose spinal anesthesia to provide stable hemodynamics for LSCS. In addition, the epidural component allows flexibility in titrating block height to facilitate prolonged surgical time.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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