1. CIPA is a rare hereditary sensory autonomic neuropathy. It was first reported by Swanson in 1963[12]. There were few reports of CIPA in the previous literature. CIPA is more common in men, and all three patients in this study are female. Dyck named these diseases as Hereditary sensory and autonomic neuropathy (HSAN)[13]. HSAN has been categorized into 5 types: HSAN type I (Hereditary sensory radicular neuropathy), HSAN type II (Congenital sensory neuropathy), HSAN type III (Familial dysautonomia), HSAN Type IV (CIPA), and HSAN type V (Congenital insensitivity to pain with partial anhidrosis)[2, 14]. The three cases reported in this study belong to type IV (CIPA).
2. The diagnosis of CIPA is based on pain, temperature test and iodine starch sweating qualitative test[15]. Further diagnosis requires molecular biotechnology to find out the location of gene mutation. In this study, all 3 cases are investigated by the above methods, and skin biopsies were performed in another hospital, which showed a loss of unmyelinated fibers of peripheral nerve, denervation of skin nerve and abnormality of exocrine gland. All the evidence supports the CIPA diagnosis.
3. Rectal thermometry is recognized as the most accurate surrogate of body temperature, especially for hyperthermia patients[9]. CIPA has a great impact on body temperature, so it is necessary to monitor the temperature of patients after operation. The axillary temperature is not accurate when the core body temperature is abnormal. We must pay attention to prevent death due to secondary infection caused by hyperthermia.
CIPA, as a rare sensory autonomic neuropathy, affects sweating and heat dissipation. In this study, we first tried to use rectal and axillary temperature to reflect the trend of postoperative temperature change. Secondly, we tried to explain the cause of the temperature change. The time course of temperature showed two peaks, on the first day and 5–7 days after surgery, respectively. The changing trend of rectal and axillary temperature is similar, but the sensitivity of axillary temperature is not as good as that of the rectal temperature. Axillary temperature is easy to cause false-negative results, especially in the early postoperative period. It is suggested that rectal temperature should be used to reflect the temperature changes, especially in the early postoperative period.
The reasons for two peaks: the peak on the first day after surgery is considered to be related to surgery; the second peak on the 5–7 days after surgery is considered to be a fever following the removal of the drainage tube. CIPA patients’ bone healing is slow and poor [14, 16, 17], so they always get out of bed later than the regular patients. Before the removal of the drainage tube, the patients have to lay in the bed all the time. The surgical trauma is substantial, and there is much bleeding. After the removal of the drainage tube, there will be blood or fluid accumulation in the body, which leads to the second peak.
4. CIPA is similar to spinal cord injuries, especially the cervical spinal cord injury, because they all have sensory autonomic neuropathy, which can affect sweating and heat dissipation. Therefore, our study uses physical cooling to prevent hyperthermia caused by spinal cord injury, and it has achieved good results. Although CIPA patients are insensitive to drug cooling, we can still use aspirin/lysine to reduce their temperature by lowering the temperature set-point. It is confirmed that to some extent the method of CIPA postoperative temperature control can be applied the treatment of spinal cord injury.
5. CIPA combined with Charcot spine should have 360 °fusion, postoperative position management is very important. Vialle reported 9 cases of CIPA with Charcot spine and emphasized the importance of 360 °fusion. He pointed out that due to the lack of pain protection mechanism, the repeated excessive activity of patients is easy to cause the failure of internal fixation even in case of a simple posterior fusion [18]. Therefore 360 °fusion was performed in all 3 CIPA patients. 360 °fusion can provide the most powerful stability to prevent the internal fixation failure caused by excessive activity. 360 °fusion is important, but postoperative position management is also important. The position management is particularly important in the early postoperative period, especially in the period before the internal fusion is completely stable. Our method that ensure patients always wear braces during the whole process from lying position to standing position and from standing to lying position can disperse the stress of spine.
6. The BMI of one patient was only 14.0(malnutrition) before surgery. Through our nutritional intervention, this patient returned to normal before discharge from the hospital. This result can confirm that our approach can really help patients.