Analysis Of Clinical And Imaging Features Of Intradural Lumbar Disc Herniation

Purpose: The goal of this study was to look at the clinical and imaging aspects of Intradural lumbar disc herniation（ILDH）in order to better understand the condition,establish a foundation for diagnosis,and look into treatment options.Materials and methods: Clinical data of 7 patients with intra-dural lumbar disc herniation clearly diagnosed by surgery at China-Japan Union Hospital of Jilin University from July 2017 to October 2021 were collected and analyzed.Risk factors,clinical manifestations,imaging manifestations,surgical treatment methods and efficacy,pathological findings and short-term outcomes were retrospectively analyzed and followed up for a period of 1 month to 6 months.A retrospective analysis of the literature was conducted,and the keywords "subdural","intradural",and "lumbar disc herniation" were used to search the China national knowledge infrastructure,Wanfang,and Vipul databases,and the keywords "Intradural","Intradural",and "Intradural" were used to search the database."Intradural","lumbar disc herniation","Intradural disc rupture The keywords " Intradural "," lumbar disc herniation","Intradural disc rupture",etc.were used to search Pub Med literature related to intradural lumbar disc herniation published at home and abroad from January 1985 to July 2021,and 131 cases were collected by excluding incomplete clinical data,duplicate cases and cases with concurrent intravertebral tumors.The incidence of gender,age,segmentation,distribution of symptoms on the right and left side,type of herniation and cauda equina syndrome were statistically analyzed.Results.1.Among the 7 patients in our hospital,a comprehensive analysis of this condition was performed in combination with our group of cases.3 cases of lesioned segments L2-3,1 case each of L1-2,L3-4,L4-5,and L5-S1.The clinical symptoms were more severe in 7 patients than in the epidural lumbar disc herniation,and in 3 cases the clinical signs did not correspond to the imaging findings,such as the presence of clinical symptoms below the onset segment,resulting in blurred nerve root localization..The proportion of cauda equina syndrome was increased compared to epidural lumbar disc herniation,with three of the seven patients presenting preoperatively with saddle sensory disturbance and urinary disturbance,and one with sexual dysfunction.Preoperatively,ILDH was suspected in cases 1,2,and 7.case 1 was a disc herniation in L2-3 segment with preoperative hypotonia of the lesser dorsal extensor muscles,low signal irregular intra-dural occupational shadow and disc fragmentation sign;case 2 had cauda equina syndrome preoperatively,CT horizontal showed sharp rostral edge of the herniated disc,MRI showed rupture of the posterior longitudinal ligament,low signal irregular intradural occupational shadow,and L4-5 segment The "Y" sign and "hawk’s beak sign" were seen in the ventral dura;case 7 showed lower extremity symptoms after preoperative sprain,and preoperative enhanced MRI showed circumferential enhancement.In six cases,the surgical approach was posterior lumbar laminectomy for decompression,and in five cases,the dural sac was sutured after dural dissection and removal of the intervertebral disc.Postoperative symptoms of lower extremity and defecation disorders were relieved.2.The largest study of 131 patients in the literature search collected information on a total of 12 patients with ILDH,all 12 patients were clearly diagnosed intraoperatively,and the authors concluded that the severity of pain and neurological symptoms was more severe in the patients than in the epidural ones,with irregular edges of herniated discs,hawk-like herniated discs on MRI,abrupt disruption of the posterior longitudinal ligament,ventral dura on "Y" sign,disc material outside the posterior longitudinal ligament,calcification or ossification of the herniated disc,and a ratio of maximum sagittal diameter of the disc/maximum sagittal diameter of the spinal canal greater than 0.6 were all helpful in the diagnosis of ILDH.Preoperative imaging in 7 of our diagnosed patients also showed the above imaging,but 1 of them showed a gas shadow at CT,which also contributed to the diagnosis of ILDH.128 of the 131 patients had herniations located within the dural sac（97.7%）,including 1 within the dural sac and outside the arachnoid.2 cases had herniations inside the nerve root sheath on one side（1.5%）.Conclusions: 1.The incidence of ILDH is low,and preoperative and intraoperative misdiagnosis is relatively common.When there are some characteristic imaging manifestations,it is reasonable to suspect the occurrence of ILDH.2.The preoperative symptoms of ILDH may not match the signs and imaging manifestations,and it is more likely to have cauda equina syndrome with many postoperative complications.Postoperatively,the patient’s symptoms may be improved and surgery is recommended.