In total, 12 severe rigid thoracolumbarspine deformity patients received a PEO at T12 or L1. The three-dimensional model provided accurate diagnostic and better surgical options. The kyphosis and scoliosis correction rates reached 77.0 ± 8.9% and 75.5 ± 8.0%, respectively. The mean intraoperative estimated blood loss was 1950 ± 1050 mL and the mean operative time was 6.98 ± 4.02 h. Osteotomies were all performed at T12 or L1. Three patients had typical symptoms of L1 nerve root injury. Specifically, the lower limb exhibited weakness on knee extension and hip flexion, and the inner thigh felt numb (Table 1). Table 2 and 3 shows SF-36 scores of the patients at baseline, one year, 18 months and 24 months postoperatively, respectively. The SF-36 scores of physical function, role-physical, bodily pain, general health, vitality, social function, role-emotional and mental health changed from 63 ± 28, 50 ± 25, 50 ± 30, 34 ± 19, 53 ± 28, 45 ± 30, 30 ± 36 and 54 ± 18 at baseline to 83 ± 18, 69 ± 19, 72 ± 12, 66 ± 21, 75 ± 15, 72 ± 22, 66 ± 34 and 76 ± 12 at one year postoperatively , 83 ± 8, 68 ± 32, 83 ± 17, 73 ± 17, 82 ± 18, 76 ± 26, 70 ± 37 and 88 ± 12 at 18 months postoperatively, 86 ± 6, 83 ± 33, 90 ± 16, 81 ± 16, 89 ± 14, 88 ± 25, 83 ± 17 and 94 ± 10 at 24 months postoperatively, respectively (P < 0.01, Student's t test), indicating that the quality of life of the patients improved significantly after PEO.
However, although the clinical effect of the PEO technique was obvious, complications were unavoidable. L1 nerve roots injury occurred in 3 patients, with abnormal SEP and MEP waveforms during the operation that was confirmed by lower limb EMG after surgery. The symptoms of L1 nerve root injury were significantly improved by pharmacotherapy with mannitol and methylprednisolone and nutritional neurotherapy. We could see that L1 nerve root function was obviously improved by continuously monitoring EMG of both lower limbs. Meanwhile, 1 case developed hemopneumothorax, which was effectively repaired without any leakage, and a closed thoracic drainage tube was placed post operation. One patient experienced paralytic ileus which improved after gastric decompression, promoting intestinal motility and symptomatic medical treatment. At one year follow up, we did not observe any other complications, such as dura laceration, superficial infection, nonunion/rod breakage, distal screw loosening and adjacent segment kyphosis (Table 4).
Data Analysis
A Student's t test was used to evaluate the differences after surgery. Statistical significance was set at a value of P < 0.01. Data are displayed as mean ± SD unless otherwise indicated.
Case 1
A 33-year old housewife had waist deformity for 18 years that worsened over the last year. The spine deformity was serious. In the flexion test, the left side of the waist was raised 10 cm, the muscle strength of both lower limbs was grade V, and the patient had normal sensation. The preoperative diagnosis was severe rigid thoracolumbar deformity; kyphosis Cobb 85° and scoliosis Cobb 67° was determined by X-ray after bending (Figure 2A). Osteotomy was performed at T11 and T12, and the upper and lower end vertebrae were T8 and L4 (Figure 2B). Due to position variation, we mistakenly identified L1 as the T12 nerve root, and damaged the L1 nerve root on the convex side of the side bend with abnormal waveforms by SEP and MEP during the operation (Figure 2D). Despite postoperative kyphosis and scoliosis correction to Cobb 12° and 15° (Figure 2C), knee extension and hip flexion of the left lower limb were weak (grade Ⅲ), and the inner thigh was numb. We reconfirmed L1 nerve root injury by lower limb EMG after surgery. After pharmacotherapy with mannitol and methylprednisolone and nutritional neurotherapy, the muscle strength of the left lower limb recovered to grade IV, and numbness was relieved before the patient was discharged from the hospital. At one year follow-up after surgery, the patient still had left lower limb weakness, which had an impact on daily life.
Case 2
A 21-year old delivery man had waist deformity for 10 years that was worsened over the past 4 years. In the flexion test, the left waist was raised 8 cm, the muscle strength of both lower limbs was grade V, and there was no numbness. The preoperative diagnosis was severe rigid thoracolumbar deformity; kyphosis Cobb 90° and scoliosis Cobb 130° was determined by X-rays after bending (Figure 2A). Osteotomy was performed at T12 and L1, and the upper and lower end vertebrae were T5 and L5 (Figure 2B). Due to high tension, we mistakenly damaged the L1 nerve root on the convex side with abnormal waveforms by SEP and MEP during the operation (Figure 2D). Despite postoperative kyphosis and scoliosis correction to Cobb 25° and 40° (Figure 2C), knee extension and hip flexion of the left lower limb were grade II, and the inner thigh was numb. After surgery, L1 nerve root injury was confirmed by EMG. After a period of therapy, the muscle strength of the left lower limb recovered to grade IV, and numbness was markedly reduced before the patient was discharged from the hospital. At one year follow-up, the patient could not go up the stairs smoothly, which had an impact on his work.
Case 3
A 22-year old male had waist deformity for 8 years that was worsened over the preceding two years. In the flexion test, the left side of the waist was raised 14 cm, and the muscle strength of both lower limbs was grade V, indicating serious spine deformity (Figure 3A). Preoperative diagnosis was severe rigid thoracolumbar kyphosis, with a kyphosis Cobb angle of 102° and a scoliosis Cobb angle of 118° as judged by X-ray after bending (Figure 3B, 3C and 3D). Osteotomy was performed at L1 and L2, and the upper and lower end vertebrae were T8 and S1. During the operation, we observed that the L1 nerve roots on the convex side of the scoliosis were pulling tension and easily damaged (Figure 3E). We tried to use nerve strippers to separate and protect the L1 nerve root while maintaining normal waveforms by SEP and MEP during the operation (Figure 3F). The L1 nerve roots were slack and floating in the gap (Figure 3E). Kyphosis and scoliosis were corrected to Cobb 32° and 35°, respectively, postoperatively (Figure 3G) and the patient had no symptoms of nerve root injury.