| Background:Tethered cord syndrome（TCS）is a kind of syndrome of spinal cord,nerve root and cauda equina nerve fixed by inelastic structure caused by heredity,development or postnatal factors.In the process of growth and development or movement,the blood supply of spinal cord and nerve changes under certain traction,resulting in the damage of its oxidative metabolism function,and a series of clinical syndromes represented by malformation and neurological dysfunction.TCS has not only traction injury of spinal cord cone,but also traction injury of nerve and nerve root.Only surgical treatment can reduce the traction of spinal cord and nerve,and create favorable conditions for the recovery of neurological function of TCS patients.The traditional method of terminal wire cutting has not achieved satisfactory results.Under the condition of fully studying the pathological mechanism of TCS,our research team proposed the Homogeneous Spinal-Shortening Axial Decompression（HSAD）surgery.Combined with multi-level discectomy,multi-level osteotomy and other technologies,the tethered spinal cord was evenly decompressed and good therapeutic effect was obtained.Magnetic resonance Imaging（MRI）is the best method for anatomical imaging of spinal cord at present.Many diseases can preliminarily evaluate the degree of spinal cord damage and prognosis through morphological changes.Conventional MRI can know whether there is ligament thickening and calcification,spinal canal stenosis,the degree of disc bulging and protrusion,the degree of dural sac and corresponding spinal cord compression,and judge whether there is degeneration of spinal cord.In recent years,the development of DWI technology provides a new way for clinical evaluation of TCS.Due to the slender and small anatomical shape of the spinal cord and the pulsating effect of cerebrospinal fluid around the spinal cord,the conventional diffusion-weighted imaging technology is easy to produce volume effect,and the apparent diffusion coefficient（ADC）measurement value has a large deviation,even the magnetic field is not uniform enough,leading to the production of magnetic susceptibility artifacts.Multi-shot Diffusion weighted imaging（ms-DWI）is based on the common diffusion weighted imaging to achieve high-definition imaging.Urinary dysfunction accounts for a high proportion in TCS patients,of which urinary incontinence is the most common complaint.If effective treatment is not given for a long time,bladder compliance and coordination will continue to deteriorate,bladder residual urine is too much,bladder internal pressure will increase,which will further lead to high renal pressure,urine reflux,seriously affect renal function,and even cause renal function damage until failure.Normally,the afferent part of bladder and urethra receives the information of periaqueductal gray（PAG）from insular lobe,anterior cingulate cortex（ACC）and prefrontal cortex.In the stage of continence,these superior central nerves control the micturition center of pons to inhibit micturition.In patients with bladder hyperactivity,the response area of the brain is different,and the cortical response becomes too large,especially in the anterior cingulate cortex and auxiliary motor area,which may be the signal of arousing emergency urination.The auxiliary motor area is activated when the pelvic floor muscles contract,providing protection against urinary incontinence.The control of the nervous system on micturition is stratified.The mechanism of the spinal cord storing urine is controlled by the complex switch mechanism from the brain.Under normal circumstances,micturition depends on the reflex of the medulla oblongata of the spinal cord.During the period of holding urine,the afferent nerve signal from the bladder and urethra passes through the synapse of the spinal cord center to the PAG of the midbrain,which may provide the inhibitory efferent signal from the PAG to the pons.If the threshold value is exceeded,the signal will be transmitted to pontine micturition center（PMC）.The excitation of PMC will activate the outgoing signal of downward movement,which will lead to relaxation of sphincter and pelvic diaphragm,and excitation of parasympathetic pathway will lead to contraction of detrusor.The basic concept of micturition nerve control from bladder spinal cord brain stem has been mature.However,the loop from the higher central control of urination is not clear.Objective:1.To confirm the safety and efficacy of HASD in the treatment of tethered cord syndrome（TCS）,and to compare the safety and efficacy of different age groups;2.To verify the internal consistency and reliability of HD DWI in the treatment of tethered cord syndrome（TCS）,and to explore the correlation between the apparent diffusion coefficient（ADC）and the severity of clinical manifestations and postoperative efficacy;3.In order to provide a basis for the treatment of urinary incontinence in the future,we studied the brain functional MRI of normal volunteers,patients with urinary incontinence and patients with urinary incontinence after HSAD operation.Methods:1.The clinical and imaging data of 43 patients with tethered cord syndrome admitted to Shanghai Changzheng Hospital from January 2017 to January 2019 were analyzed retrospectively,including 23 in children group and 20 in adults group.Preoperative and postoperative neurological function and pain were evaluated by JOA and VAS.Micturition function was assessed by the international consultation on incontinence questionaire short form score（ici-q-sf）and urodynamic examination,and stool function was assessed by the rintala score.Observation and comparison of the two groups before and after the operation.2.ms-DWI was used in 31 patients with tethered cord syndrome who were admitted to Shanghai Changzheng Hospital from August 2017 to June 2019 and underwent axial decompression of spinal cord with uniform spinal shortening.Among them,14 were male and 17 were female.The LADC and r ADC of each patient were measured independently by two spinal surgeons.The internal correlation coefficient（ICC）,bland and Altman diagram and Spearman coefficient were used to measure The repeatability of test and retest and the reliability between raters were quantified.Pearson correlation analysis was used to compare LADC,r ADC and clinical efficacy.3.From June 2018 to December 2019,the subjects of this study are all right-handed adult women,9 healthy female volunteers in the normal control group,10 patients in the pre-operative TCS case group,and 8 patients in the post-operative TCS case group after hsad operation.During the scanning process,the designed task instructions are completed,"Irrigation","holding urine","urination"and"rest"are task blocks.In one MRI scan of brain function,task blocks should be repeated four times.All image data processing uses feat,through motion correction,slice timing correction,functional image registration,standard spatial registration,spatial smoothing,high pass time filtering,generalized linear model to carry out statistical analysis on the smoothed image,and the resulting mapping data is converted into unit normal distribution data,which is converted into Z-value statistics.The activated areas of the brain in different groups were displayed during micturition and continence.Result1.After HSAD operation,43 patients with TCS had significant improvement in the average VAS score and the average lumbar JOA score.According to the average RR of lumbar JOA（55.1%±12.6%）,the overall neurological function recovery was in a good range,72.0%of the patients had a good recovery,23.3%of the patients had a general recovery rate,while 4.7%of the patients had a poor recovery rate.In addition,38 of the 43patients had dysuria,accounting for 88.4%of the total TCS patients,which was mainly manifested as urinary incontinence.After HSAD operation,the ICI-Q-SF score decreased from 16.0±1.9 to 4.9±1.4（P<0.001）,the compliance improved significantly,from 7.3±11.8 ml/cm H2O before operation to 14.1±13.4 ml/cm H2O after operation（P<0.001）,and the residual urine decreased significantly,from 102.7±85.8 ml decreased to 59.5±75.2 ml after operation（P=0.041）,and the maximum flow rate increased from 5.7±3.9 ml/min before operation to 9.0±5.8 ml/min after operation（P<0.001）.The objective index TL value representing sphincter coordination also increased from 0.23±0.37 before operation to 0.27±0.30 after operation（P<0.001）.In addition,10 patients in this group had intestinal dysfunction before operation,8 patients（80%）improved after operation according to the evaluation of rintala score,while 2 patients had no change in rintala score before and after operation.2.At the same time,the operation time of HSAD in children and adults with TCS was192.3±23.4 minutes,slightly higher than 184.3±18.3 minutes in adults,but the difference was not statistically significant.At the same time,the amount of bleeding in children was 443.1±91.3 ml,slightly less than 456.3±90.2 ml in adults,but the difference was still not statistically significant.3.In terms of the effectiveness of HSAD operation,there was no significant difference in VAS score and JOA score of lumbar vertebrae before and after operation between the children group and the adult group,while at the last follow-up,JOA score of lumbar vertebrae in the children group was 22.5±1.3,significantly higher than that in the adult group,which was 21.3±2.3.In terms of the improvement rate of neurological function,although both the children’s group and the adult group achieved a good degree（50%-75%）,58.9%±8.0%in the children’s group was significantly higher than 50.8%±15.4%in the adult group.The preoperative ICI-Q-SF score of the children group was 16.0±1.9,which was equivalent to that of the adult group.At the last follow-up,the ICI-Q-SF score of the children group was 4.2±1.0,which was significantly better than that of the adult group（5.6±1.4）.4.In the analysis of repeatability and reliability between raters,ICC value of ADC value at T12/L1 is 0.997,ICC value of LADC value is 0.997,ICC value of r ADC is 0.994,the results are higher than 0.80,so it is considered as excellent retest reliability;in bland and Altman plot,the bias of ADC value at T12/L1 is 0.5806,and 95%confidence interval is-16.85-18.01,the bias of LADC value was 4.548,95%confidence interval was-21.46-30.56,the bias of r ADC was 0.005806,95%confidence interval was-0.02611-0.03772,the three indexes were measured in bland and Altman The scatter points of plot map are evenly distributed in the upper and lower range of 95%confidence interval,and the mean value is close to 0,indicating that the two measurement results are relatively close,with good consistency;Spearman coefficient of ADC value at T12/L1 is 0.991（P<0.0001）,Spearman coefficient of LADC value is 0.997（P<0.0001）,Spearman coefficient of r ADC is 0.987（P<0.0001）,and coefficients greater than 0.90 indicate excellent reliability of different observers.Therefore,ms-DWI has good repeatability and interobserver reliability.5.There was no correlation between the ADC value of T12/L1 and the clinical symptoms and the effect of 6 months after operation.There was a significant correlation between the ADC value and the JOA score of lumbar spine before operation（r=0.5178,P=0.0028）,and a significant correlation between the ADC value and the JOA score of lumbar spine at 6 months after operation（r=0.4864,P=0.0055）,and a significant correlation with RR（r=0.3773,P=0.0364）,but r ADC had stronger correlation than LADC,and r ADC had significant correlation with preoperative lumbar JOA score（r=0.7110,P<0.0001）,6-month postoperative lumbar JOA score（r=0.7271,P<0.0001）,and RR（r=0.6233,P=0.0002）.In addition,there was no significant correlation between LADC value and micturition related score and quantitative index（ICI-Q-SF score,bladder compliance,TL value,residual bladder urine,maximum urine flow rate）before and 6months after operation,but there was significant correlation between r ADC and preoperative ICI-Q-SF score（r=0.5829,P=0.0006）,and there was significant correlation between them（r=0.7034,P<0.0001）,no significant correlation with preoperative compliance（r=-0.7833,P<0.0001）,no significant correlation with postoperative compliance at 6 months（r=0.7164,P<0.0001）,and significant correlation with postoperative maximum urine flow rate at 6 months（r=0.4265,P=0.0167）.6.The areas of brain activation during urination included parietal lobe,frontal lobe,cerebellum,temporal lobe,cingulate gyrus,auxiliary motor area and caudate nucleus.The brain activation areas in the period of suffocation include parietal lobe,frontal lobe,cerebellum and temporal lobe,which are the same as that in the period of urination.At the same time,it has its unique activation areas including amygdala,insula,thalamus,basal ganglia and occipital lobe,while cingulate gyrus and auxiliary motor area are not activated in the period of suffocation.7.The brain activation areas of TCS patients during micturition include parietal lobe,frontal lobe,temporal lobe,cingulate gyrus,amygdala,thalamus,occipital lobe and putamen.Among these activated areas,parietal lobe,frontal lobe,temporal lobe and cingulate gyrus were activated during urination in volunteers,while amygdala,thalamus and occipital lobe were not activated during urination in volunteers,but they were activated during urine holding in volunteers,while the activation of putamen was the unique area of brain activation during urination in TCS patients.The brain activation areas in the period of suffocation include parietal lobe,frontal lobe,temporal lobe,insula,caudate nucleus,thalamus and auxiliary motor area.Among these activated areas,the parietal lobe,frontal lobe,insula,thalamus and temporal lobe were also activated during the urine holding period of volunteers.The basal ganglia and occipital lobe activated during the urine holding period of volunteers did not appear in the brain activated area during the urine holding period of TCS patients,while the auxiliary motor area appeared in the brain activated area during the urine holding period of TCS patients and did not appear in the urine holding period of volunteers.Compared with the period of urination in TCS patients,the parietal lobe,frontal lobe and temporal lobe are activated in two periods.The cingulate gyrus,amygdala,thalamus,occipital lobe and putamen are activated in TCS patients during urination,while the insula,caudate nucleus,thalamus and auxiliary motor area are activated in TCS patients during urination.8.After HSAD,the areas of brain activation in patients with TCS include parietal lobe,frontal lobe,temporal lobe,occipital lobe,pons and cerebellum.Compared with patients with TCS before operation,there are common activation areas such as parietal lobe,frontal lobe,temporal lobe and occipital lobe,but cingulate gyrus,amygdaloid nucleus,thalamus and putamen nucleus are not activated after operation,while pons and cerebellum are additional activation areas after operation.After HSAD,the areas of brain activation in patients with TCS include frontal lobe,temporal lobe,occipital lobe,pons,cerebellum and caudate nucleus.Compared with patients with TCS before operation,frontal lobe,temporal lobe and caudate nucleus were not activated together,while parietal lobe,insula,thalamus and auxiliary motor area were not activated before operation,while occipital lobe,pons and cerebellum were not activated after operation.Conclusion1.Children and adults TCS patients have achieved good results after HSAD surgery,72.0%of them have achieved good or above neurological recovery rate,there is no significant difference in the safety of surgery,and there is no serious complications.The application of this surgical method provides a new choice for TCS patients,and provides new thinking for the majority of medical personnel.2.The degree of pain relief in children’s TCS group was similar to that in adults’TCS group,but the neurological recovery and urination score were significantly higher than those in adults’TCS group,suggesting that children’s TCS patients could get better curative effect through HSAD than adults’TCS patients.3.At the last follow-up,the improvement of bladder compliance and residual urine in the quantitative value of urodynamic examination in TCS patients in children’s group was better than that in adults’group,but there was no significant difference in urinary flow rate and bladder coordination between the two groups.4.This study confirmed that ms-DWI has good repeatability and reliability among different observers in the scanning of lumbosacral spinal cord of TCS patients,and the results are stable and reliable.5.It is proved that the increase of ADC value in the lumbosacral spinal cord of TCS is related to the severity of clinical symptoms and the effect of HSAD.6.Compared with LADC value,the new index（r ADC）has stronger correlation with the severity of preoperative clinical neurological dysfunction,the improvement of neurological function after HSAD and the improvement of bladder function,which provides a certain basis for the application of ms-DWI in the field of spinal and spinal diseases in the future.7.In this study,we found that there was a difference in the location and intensity of the brain activation area between before and after HSAD in patients with TCS.The pontine and cerebellum of TCS patients were significantly reactivated during the period of urination and suffocation.We speculated that the reactivation of the above two parts might be closely related to the recovery of the urination function.8.In this study,we found that the activated area of brain function of TCS patients after HSAD was different from that of normal volunteers.This phenomenon suggests that patients may form a new brain control network after HSAD,and the recovery of urination function after operation may be related to the new brain control network of patients after HSAD,that is,during urination,the pons receives the cortical signal control from the parietal lobe,frontal lobe,temporal lobe,occipital lobe and cerebellum During the period of suffocation,the pons receive cortical signals from frontal lobe,temporal lobe,occipital lobe,cerebellum and caudate nucleus.9.The results of this study show that the physiological activities of micturition and suffocation are controlled by the key parts of the brain,and the brain function network involved in the control is more complex.The uniform decompression of the spinal cord is completed by HSAD operation,and the changes of the brain control network occur at the same time of the recovery of the spinal cord function.We speculate that it may be caused by the reverse feedback effect of the lower nerve on the upper center. |
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