Spinal Cord Specialty Group, Department of Neurosurgery, Affiliated Hospital of Inner Mongolia Medical University: Tian Fuming, Chief Physician Yan Haisheng, Attending Physician Tian Fuming, Department of Neurosurgery, Affiliated Hospital of Inner Mongolia Medical University I. Intramedullary Tumors: Intramedullary tumors include primary and secondary tumors that occur in various tissues within the spinal canal, Chordoma, lipoma Ø Extramedullary epidural tumors – metastases lymphoma, chordoma Ø Dumbbell-shaped tumors that ride across the dura and outside (a) Intramedullary tumors Clinically, they occur mostly in the 20-50 years old. Pain is the most common first symptom, and motor disorders and sensory abnormalities below the tumor segment gradually appear, manifesting as limb weakness, muscle atrophy and paraplegia, abnormal muscle tone and tendon reflexes. Ventricular meningioma is the most common intramedullary tumor (55-65%), the majority of benign intramedullary tumors grow slowly, only a small number of malignant changes occur. 40-50 years old is the peak incidence. MRI manifestations Ventricular meningioma can occur anywhere in the spinal cord and involves several segments; ventricular meningioma often consists of solid and cystic parts; the solid part has low signal on T1WI and high signal on T2WI; there is often edema around the tumor, and the abnormal signal seen on plain scan is larger than the actual size of the tumor; the solid part of the tumor has obvious enhancement on enhanced scan; the cystic part consists of necrotic liquefaction of the tumor and secondary spinal cord cavities. The cystic part is composed of necrotic liquefaction of tumor and secondary cavity of spinal cord, and the secondary cavity of spinal cord shows cerebrospinal fluid-like signal intensity. Astrocytoma is one of the most common intramedullary tumors, accounting for about 30-40% of all intramedullary tumors. It is the most common intramedullary tumor in children, with a prevalence between the ages of 10 and 25. It is mostly benign and has a good prognosis. MRI manifestation: The typical astrocytoma on MRI is quite extensive, with multiple spinal cord segments involved, mostly in the cervical and thoracic segments; in cross-section, the tumor is seen to fill the spinal cord, and normal spinal cord structures disappear. The spinal cord was diffusely thickened; T1WI showed equal or low signal, T2WI showed high signal; cystic degeneration and spinal cord cavity; injection of Gd-DTPA, the solid part of the tumor was obviously enhanced in T1WI. Angioblastoma accounts for 1%-5% of intramedullary tumors and is more common before the age of 40. 75% of angioblastomas are located in the spinal cord, mostly on the dorsal side of the spinal cord. 10%-15% of them involve both the spinal cord and the subdural area, and those located outside the spinal cord mostly involve the dorsal soft spinal membrane. They are commonly found in the thoracic and cervical segments of the spinal cord. 80% are solid lesions, 30% are combined with hemangioblastoma of the cerebellum and medulla oblongata, and benign cysts of the pancreas, kidney and ovary, manifesting as the VonHipple-Lindau syndrome. 43% of tumors are seen as intramedullary cysts, which are characteristic. Cysts may occur at the site where the tumor is located or may be completely separate from the tumor (ii) Extramedullary subdural tumors Extramedullary subdural tumors account for 60% of intradural tumors , the vast majority of which are benign, with nerve sheath tumors, neurofibromas and spinal meningiomas being the most common. Typical symptoms are neurogenic pain and later numbness, soreness and swelling of limbs or hypesthesia. 1. nerve sheath tumor is the most common intraspinal tumor, accounting for 29% of all intraspinal tumors. on MRI, the tumor shows a limited block shadow, T1WI shows a signal slightly higher than or equal to that of the spinal cord, with smooth edges, the spinal cord becomes deviated by compression or even displaced, the subarachnoid space is enlarged, the T2WI signal is higher than that of the adjacent spinal cord tissue, and after injection of Gd-DTPA, the T1WI tumor is obviously uniformly strengthened. After Gd-DTPA injection, the tumor was obviously uniformly strengthened. MRI manifestation: The tumor is a confined mass, round or dumbbell-shaped, with smooth edges and envelope. The signal of T1WI is equal to or slightly higher than the spinal cord, and the signal of T2WI is higher than the adjacent spinal cord tissue. The subdural sign: the spinal cord is deflected by compression, shifted to the healthy side, and the subarachnoid space on the side of the lesion is enlarged. After Gd-DTPA injection, the T1WI tumor is obviously uniformly strengthened. In case of cystic change, ring reinforcement was observed. 2. Spinal meningioma has the second highest incidence of intradural tumors, accounting for 25% of all intradural tumors. It mainly originates from arachnoid cells, almost all of them are benign, and is the most effective intravertebral canal tumor for surgical resection. They are more common in women, with a predilection for the thoracic segment (80%), followed by the cervical and lumbar segments, and rare in the sacral region. MRI manifestation: can clearly show subarachnoid obstruction and spinal cord compression-subdural sign. isosignal on T1WI, isosignal on T2WI or mildly elevated. After Gd-DTPA injection, T1WI showed persistent homogeneous enhancement of the tumor. The “tail of spine” sign can be seen. This disease is mostly seen in females and has a high rate of calcification. Lipoma occurs mostly under the age of 40, mainly manifests as spinal cord compression symptoms, with less pain and no radiating pain. MRI: T1WI is decisive for the diagnosis of lipoma. An abnormally large amount of high-signal adipose tissue can be seen growing longitudinally in the spinal canal. T2WI also shows high signal. 4. dermatomal cyst: (c) Extramedullary epidural tumors Extramedullary epidural tumors account for 25% of intravertebral canal tumors, and most of them are malignant. 1. metastases Most commonly seen in the elderly, pain is the most common first symptom, and severe spinal cord compression soon appears. The thoracic spine is the most common, followed by the lumbar and cervical spine, and the sacral spine is rare. The primary tumors are breast, lung and prostate cancer, followed by lymphoma, kidney cancer, melanoma, etc. MRI performance: The sensitivity and specificity of finding bone metastases are higher than that of isotopes. Irregular soft tissue masses can be seen in the epidural area, which can easily invade into the paravertebral soft tissues, and the dural sac and spinal cord can be compressed and displaced to different degrees. Tumor enhancement was seen after enhancement. Bone destruction of vertebral body, arch and adnexa. Long T1 and long T2 signals. The affected vertebral body is jumping distribution, and the intervertebral disc is normal. 2.Lymphoma Most commonly seen in men, age of onset is not consistent. It often involves the thoracic and lumbar spine and mainly manifests as symptoms of spinal cord and nerve root compression, with local pain being the most common, and gradually lower limb motor and sensory impairment and sphincter dysfunction. The diagnosis of lymphoma often requires a combination of clinical and laboratory tests for comprehensive judgment. MRI performance: MRI scan can clarify the site range of the tumor, and the signal of the involved vertebral body is reduced. The epidural high signal adipose tissue is replaced by tumor tissue, the tumor grows around the dural sac in an encapsulated sheath, and the nerve roots are often invaded. Long T1 signal with heterogeneous high signal in T2. After enhancement, the tumor is seen to be moderately enhanced. Skull base depression is a complex developmental malformation of the occipitocervical junction area, which can be divided into different types according to its anatomical and clinical characteristics. At present, the best typing method is to distinguish the common skull base depressions into two categories, stable and unstable, according to whether they are combined with atlanto-occipital or atlanto-axial instability. （Arnold-Chiari malforma-tion (ACM) is a group of syndromes manifested by the abnormal development of the posterior cranial recess midline structures during the embryonic period, resulting in the herniation of the cerebellar tonsils into the occipital foramen and causing the compression of the medulla oblongata and superior cervical medulla and increased intracranial pressure, often accompanied by spinal cord cavitation ( Syringomyelia (SM) and craniocervical deformities are often associated with this syndrome. Clinical manifestations: four syndromes. (1) Occipitocervical compression syndrome: due to subhypothalamic tonsillar herniation, the cranial nerve roots and cervical nerve roots are compressed, which can cause headache, hoarseness, difficulty in swallowing, pain in the neck and neck and limitation of movement. (ii) central damage syndrome of the medulla oblongata: due to compression of the upper cervical segment of the medulla oblongata, it can cause impaired limb movement, hemiparesis and quadriplegia, sensory impairment of the limbs, and sensory separation or atrophy of both upper limbs when combined with spinal cord cavity. (3) Cerebellar damage syndrome: ataxia, unstable walking and nystagmus may occur due to cerebellar involvement. ④When hydrocephalus is combined, it may manifest as headache, vomiting, fundus edema and other high cranial pressure symptoms. However, the clinical symptoms of the disease are variable. The surgical methods are divided into: (1) posterior cranial fossa decompression; (2) posterior cranial fossa decompression and spinal cord cavernotomy and drainage; (3) posterior cranial fossa decompression and cerebellar tonsillectomy; (4) posterior cranial fossa decompression, spinal cord cavernotomy and cerebellar tonsillectomy; (5) posterior cranial fossa enlargement and reconstruction; (6) occipital pool reconstruction, etc. The choice of surgical method depends on the specific condition. (2) Unstable skull base depression deformity – to be carried out The formation of unstable skull base depression is related to the dislocation, superior displacement and invagination of the dentate process, which can also be called dentate skull base depression. The symptoms of compression of the medulla oblongata and superior cervical medulla include sensory disturbance, muscle atrophy, hemiparesis, quadriplegia, vertigo, gait instability, dyspnea and urethral sphincter disorder, etc. The symptoms of cerebral and cervical nerve involvement include occipital and cervical pain, facial numbness, diplopia, tinnitus, hearing loss, hoarseness and dysphagia. Surgical methods: ① posterior occipital ⁃ interscalene screw repositioning orthopedic and fixation techniques; ② anterior dentate repositioning internal fixation via oropharynx; ③ oropharyngeal access atlantoaxial tooth release, dentate repositioning, posterior fixation occipitocervical fusion bone grafting. (3) complex skull base depression deformity (posterior fixation + crico-occipital decompression) (4) spinal cord cavitation (often combined with skull base depression deformity) 2, spina bifida, spondylolisthesis and spinal cord embolism three often exist together, when the terminal filament fatty degeneration, the possibility of injury to the spinal cord by external pull or hyperflexion increases, can cause spinal cord embolism syndrome, lower limb sensory function motor impairment, and even urinary and fecal This can lead to spinal cord embolism syndrome, with sensory-motor impairment of the lower extremities and even urinary and fecal impairment. For patients with symptoms, regardless of the normal appearance of the filum terminale, surgery should be performed early after detection. In addition, ventricular meningioma of the terminal filament can be complicated by spinal cord embolism, and ventricular meningioma can be removed and the terminal filament can be released at the same time. Vascular lesions 1. Spinal vascular malformation Spinal vascular malformation refers to spinal cord lesions caused by congenital abnormal development of spinal cord vessels. The symptoms are variable and the early misdiagnosis rate is high, and once misdiagnosis occurs, it often affects the patient’s prognosis. In patients with chronic onset, the first symptom is often spontaneous pain, which often manifests as pain in the thoracic and lumbar back and pain in the limbs. In patients with acute onset, most of the symptoms are due to hemorrhage from malformed vessels, such as subarachnoid hemorrhage or intramedullary hemorrhage. Sudden and severe head and neck pain or corresponding spinal cord segment pain, vomiting, meningeal irritation signs, and even loss of consciousness and respiratory impairment in severe cases are easily misdiagnosed as spontaneous subarachnoid hemorrhage. Angiography is the gold standard, and treatment is interventional embolization plus surgical resection. 2, dural arteriovenous fistula Dural arteriovenous fistula refers to the artery supplying the dura or nerve roots crossing the dura at the intervertebral foramen in communication with the spinal drainage vein, and is the most common type of spinal vascular malformation. Early detection and early treatment are important to ensure a good prognosis. Careful evaluation of the arteriovenous condition of the arteriovenous fistula prior to treatment and attempted embolization at the time of the first imaging, or partial embolization in preparation for surgery, can provide immediate relief of symptoms. If embolization fails or is inappropriate, surgical treatment can be used instead of repeated embolization. Combined treatment can overcome the shortcomings of surgery or embolization alone, and is the main means of treatment at present. Sacral cyst: Sacral cyst refers to the cystic lesion occurring in the sacral canal, and its name and classification are confusing, such as sacral spinal cyst, TARLOV cyst (perineural cyst), intra-sacral arachnoid cyst, intra-sacral epidural cyst, sacral synovial cyst and so on. Most scholars consider it to be a congenital dural diverticulum or arachnoid hernia, a congenital defect of the dura mater. Sacral canal cysts often involve the posterior branch of S2 ~ 3 nerve or dorsal ganglion, and the clinical manifestations have the following characteristics: ( 1) often have dull pain in the lumbosacral region, weakness of lower limbs, heavy numbness and other symptoms. The pain is related to the position, and is easily induced when standing, bending and squatting, and the symptoms are relieved when lying down, especially when the head is low; ( 2) the sciatica is mild, and the cauda equina symptoms are more obvious, manifesting as urinary dysfunction or sexual dysfunction and burning pain in the anus; ( 3) there is pressure pain or percussion pain in the lumbosacral region on examination, while the lumbar activities are often normal. The treatment of sacral cysts is still controversial. For asymptomatic patients found by chance, they can be observed first, and treatment will be considered if symptoms appear. Since most sacral cysts have mild clinical symptoms or no clear neurological symptoms, conservative treatment is feasible, and the methods include analgesia, anti-inflammation and physiotherapy. Surgical treatment: For sacral canal cysts with symptoms, most scholars prefer surgical treatment, and the surgical methods include traditional lamellar opening and decompression cyst removal, microplasty surgery, minimally invasive interventional treatment and so on. The indications for surgery are: ( 1) lumbosacral pain and intermittent claudication, which affects life and work, and conservative treatment is ineffective; ( 2) with lower limb sensation and muscle weakness; ( 3) perineal pain or sensory loss, defecation and sexual dysfunction; ( 4) huge cysts, obvious enlargement of sacral canal and serious destruction of vertebral plate. Treatment methods: (1) traditional surgery after sacral laminectomy, cyst excision and suture, partial excision of cyst wall muscle caulking, cyst openings and other procedures. (2) Microsurgical treatment. (3) Minimally invasive interventional treatment: In recent years, minimally invasive interventional treatment is more superior, easy to operate, less traumatic, faster disappearance of symptoms, and can be used for patients with recurrence of traditional surgery. The treatment of sacral nerve root cyst by percutaneous puncture and drainage under CT guidance can provide temporary relief of neurological symptoms. However, drainage is not widely used because it is prone to intracanalicular infection, low cranial pressure headache, cerebrospinal fluid leak formation and recurrence. Bioprotein gel injection therapy is suitable for those with severe clinical symptoms, those who have failed to undergo systematic conservative treatment and those who do not agree to undergo surgery, and those who have failed to undergo surgical treatment. Microscopic neurosurgical treatment of spinal stenosis: Spinal stenosis refers to the shortening of the spinal canal due to various causes, which compresses the dural sac, spinal cord or nerve roots and leads to the corresponding neurological dysfunction. It is associated with various factors such as abnormal spinal cord development, disc herniation, hypertrophic osteoarthropathy, ligamentous hypertrophy and calcification. Most spinal stenosis is clinically acquired. Congenital stenosis alone can be asymptomatic, with symptoms appearing only when secondary factors such as osteophytes, disc herniation or ligamentous hypertrophy develop. It occurs most often in the lumbar spine and secondarily in the cervical spine. 1. Clinical manifestations: lumbar spinal stenosis mainly manifests as low back pain, intermittent claudication, and sensory-motor disorders of the lower extremities. Cervical spinal stenosis mainly manifests as posterior neck, shoulder and back pain, upper limb weakness and radiating pain, sometimes accompanied by lower limb weakness, unstable walking, etc. 2, CT, MRI performance: cervical spinal canal anterior and posterior diameter less than 10mm can be diagnosed as spinal canal stenosis. Lumbar spinal canal with anterior and posterior diameters less than or equal to 11.5mm can be diagnosed as spinal stenosis. The anterior and posterior diameters of the lateral saphenous fossa are normally greater than 5 mm, and nerve root compression when it is less than or equal to 5 mm (2 mm) can be diagnosed as lateral saphenous stenosis. In the sagittal plane, T1WI shows narrowing of the subarachnoid space, occlusion, spinal cord compression and deformation. 3, spinal neurosurgery advantages: minimally invasive, microscopic, greatly reducing surgical side injuries, and the protection of the structures in the spinal canal is significantly improved. New technology: 1, electrophysiological monitoring assisted microsurgery for spinal cord intramedullary, conus and end filament tumors: neuroelectrophysiological monitoring with microsurgery can effectively improve the rate of total tumor resection and prevent intraoperative nerve injury. 2.Intraoperative fluorescence imaging aids microsurgery to remove spinal cord vascular malformation. 3.Surgical treatment of unstable skull base depression deformity. 4.The development of spinal internal fixation techniques after spinal cord surgery: internal fixation of laminar repositioning connecting plates after tumor resection; for surgery of spinal stages with high mobility (such as cervical and lumbar spine); for multi-stage hemivertebral or laminectomy using nail rod fixation to improve spinal stability; for tumors spanning inside and outside the spinal canal, the use of internal fixation after surgery. 5.Bioprotein gel injection for sacral cysts. 6.Microsurgical cyst wall muscle filling for sacral cysts.