A 46-year-old male (body weight 69 kg, ASA status II) was scheduled for right total hip arthroplasty (THA). He suffered from ankylosing spondylitis for 20 years. Physical examination indicated that the cervical and lumbar spine was rigid and the right hip joint was immobilized. The bamboo-like changes of spine were found in the spinal anterioposterior and lateral radiographs (Fig. ). X-ray and CT examination indicated degenerative osteoarthrosis of bilateral hip joints and sacroiliitis on the right side. The patient appeared potentially difficult to be intubated as the examination of airway revealed that the interincisor distance was 2 cm and a Mallampati class III. The preoperative visual analog scale (VAS) score of this patient was 4. This patient received ultrasound-guided lumbar SNRB plus T12 paravertebral and sacral plexus blocks, and 25 mL of 0.4% ropivacaine was used. Pinprick test was used to confirm the success of these blocks. The time of surgery was 1 hour and 26 minutes. He also did not complain any painful during surgery and in PACU. With the PCA, the postoperative VAS scores were 0 to 1. This patient discharged on the second day after surgery. No postoperative complication was reported with him.
Case 3: A 26 years old female (weight 47 kg, ASA status II) was scheduled for left total hip arthroplasty. She was diagnosed with ankylosing spondylitis 14 years ago, with pain on almost all major joints of her body. She could not stand or walk because of bilateral femoral head necrosis. She had a family history of ankylosing spondylitis, with her father also suffered from this disease. Physical examination revealed rigidity of neck and left hip joint. X-ray of the thoracic and lumbar vertebrae reported rigidity of the spine, calcification of interspinous ligament. X-ray of bilateral sacra-iliac joints, hip joints, knees and ankles reported narrow joint space, osteoproliferation, bone defect and joint deformity. The chest X-ray reported texture enhancement of bilateral lungs and infection of right lower lobe.