Anaesthetic Management of Post Polio Scoliotic Patient forFracture Femur Reduction

Introduction

Kyphoscoliosis is a spinal deformity with anterior flexion (kyphosis) and lateral curvature (scoliosis) of vertebral column. About 80% of cases are of idiopathic in origin, which begins during late childhood and may progress in severity during periods of skeletal growth. The rest 20% are associated with poliomyelitis, cerebral palsy, osteogenesis imperfecta, Hunter´s disease etc.¹ Long standing poliomyelitis results in progression of spinal deformity due to changes in the spinal axial movement dynamics. When severe, and involving thoracic vertebra, it can lead to restrictive lung disease and cor-pulmonale. The reduced lung compliance and restrictive pattern are inversely related to the angle of curvature (Cobb Angle). It is diagnosed when Cobb’s angle is >10° . Changes in pulmonary and cardiac function start at angles >40° and if > 60° - 65° significant respiratory manifestations are seen.^2,3 Central neuraxial blockade may be challenging due to difficulty in identification of intervertebral spaces, unpredictable pattern and level of the block and difficulty in patient positioning.⁴ The disease is associated with motor neuron loss, disturbed autonomic nervous system and risk of myopathies. The patients may respond with increased sensitivity to sedative drugs, non-depolarising muscle relaxants; use of succinylcholine may precipitate hyperkalaemia.⁵ We report a case of paralytic poliomyelitis associated lumbar scoliosis with fracture of left femur shaft who successfully underwent closed reduction and internal fixation (CRIF) with Titanium Elastic Nailing System (TENS) under spinal anaesthesia.

Case Report

A 39-year-old male patient with American Society of Anesthesiologists (ASA) physical status II presented to tertiary care centre with history of road traffic accident resulting in fracture of mid shaft of left femur. He was a known case of paralytic poliomyelitis with acute infection at two years of age. There was progressive motor weakness of both the lower limbs and lumbar scoliosis later. There was no history of any shortness of breath, no history of repeated chest infections or any other symptoms suggestive of cardiorespiratory instability. He was 155 cm in height, weighing approximately 55 kg with pulse rate of 96/min, BP 130/80 mm Hg, RR 16 cycles/min and room air oxygen saturation 99% (SpO2 ). He had limited movements in both the lower limbs with motor power of 1/5. Airway examination revealed modified Mallampatti class 2 and lumbar spine was grossly deviated to the left (Figure 1) and intervertebral spaces were relatively well felt at L1-L2 and L2-L3 interspaces. Cardiorespiratory examination was found to be normal. Haemoglobin was 15 gm/dl and blood urea, serum creatinine, blood glucose and electrolytes were within normal limits. X-ray spine revealed lumbar scoliosis with convexity towards left side. Cobbs’s angle of 80° measured taking upper most tilted vertebra as T11 and lower as L5 vertebra (Figure 2). ECG and chest x- ray were normal. 2D echo was normal with restrictive lung pattern on PFT assessment with FEV1 70%, FVC 75% and FEV1 /FVC more than 80%.

The anaesthesia technique and risks were explained to the patient and his relatives and written consent was obtained. IV line was secured with 18G cannula and preloaded with Ringer lactate 15 ml/kg. Electrocardiogram, non-invasive blood pressure and pulse oximetry were connected and basal values were noted. As sitting position was uncomfortable to the patient and as he had left sided lumbar scoliosis with fracture of left femur, spinal anaesthesia was performed with 10 mg of 0.5% Bupivacaine heavy at L2-L3 intervertebral disc space with 25G Quincke needle directed towards the convexity of curve by midline approach in left lateral decubitus position. He was put in the same position for 5 min and later turned to supine. After confirming the sensory block up to T10 dermatomal level and complete motor blockade (modified Bromage scale 3), surgery was allowed to begin. Vital parameters were monitored throughout the surgery. Back support and extremity support were ensured by keeping the pillows. Surgical procedure lasted for about 90 minutes.

Patient was observed in post-operative recovery unit for 24 hours and vital parameters were monitored. Later he was shifted to the ward. Sensory block lasted up to 4 hours postoperatively. Post-operative analgesia was provided with Inj Tramadol 50 mg IV tid and Inj Paracetamol 1 gm IV tid. Remaining part of the postoperative period was uneventful. He was discharged after 10 days from the hospital.

Discussion

The choice of using either general or regional anaesthesia in patients with kyphoscoliosis secondary to poliomyelitis should be based on pre-operative assessment, type of surgery and patient requirements.

If general anaesthesia with tracheal intubation is planned, increased sensitivity to non-depolarizing muscle relaxants is expected5 and it is advised to use short acting muscle relaxants such as rocuronium or mivacurium along with titrating doses based on neuromuscular monitoring devices. The depolarising muscle relaxants like succinylcholine may precipitate hyperkalaemia, severe post-operative pain; so it is avoided. Autonomic system dysfunction may lead to gastroesophageal reflux, tachyarrhythmias and uncontrollable hypotension. Patients with poliomyelitis are often sensitive to sedative medications resulting in delayed recovery. Over sedation and weakness results in respiratory weakness and even death due to central neuronal changes in reticular activating system from original disease.⁶

Sedative medications administered during perioperative period needs vigilant respiratory monitoring.

In the current case, we carefully performed spinal anaesthesia with monitoring from intra operative to postoperative period resulting in a successful outcome.

A successful management of 32 patients with scoliosis (Cobb’s angle >15°) who underwent elective lower limb orthopaedic soft tissue release under spinal anaesthesia was reported.⁸ Another case report of a patient of postpolio syndrome with head injury who was posted for intramedullary nailing of right femur done successfully under spinal anaesthesia was reported.⁹ Spinal anaesthesia has also been reported with successful outcomes for caesarean section in parturient with poliomyelitis associated kyphoscoliosis.¹⁰

A prospective observational study reported successful subarachnoid block in patients with Cobb’s angle less than 50° which needed median spinal needle angulation of 4±2.45° and 9.14±2.45° for Cobb’s angle more than 50°. They also observed that failed subarachnoid block was more in right sided scoliosis and Cobb’s angle more than 50°. Disparity in drug spread after spinal anaesthesia was more in right sided curve.⁴

Use of modified paramedian approach,¹¹ Taylor’s approach, and ultrasound assisted subarachnoid block can enhance the success of spinal anaesthesia.

Conclusion

Spinal anaesthesia can be associated with successful outcomes when carefully performed with attention to monitoring and proper positioning of the patient, during and after the procedure. Severity of kyphoscoliosis, secondary neurological and cardiorespiratory comorbidities related to paralytic poliomyelitis and the vertebral deformity are to be assessed along with their anaesthetic implications.

Conflicts of interest

None.