Syringomyelia: Diagnosis and Acupuncture Treatment

Syringomyelia is a chronic progressive degenerative disease characterized by the formation of a cavity (syrinx) within the central portion of the spinal cord due to various causes. This cavity may extend upward into the medulla oblongata (referred to as syringobulbia) or downward into the thoracic or even lumbar spinal cord. It presents as a syndrome of dissociated sensory loss, muscle atrophy, and neurotrophic disturbances.

The etiology and pathogenesis of this disease are not yet clearly understood. Several theories have been summarized as follows:

1. Congenital Developmental Anomalies

Due to congenital developmental anomalies, such as incomplete closure of the neural tube or impaired formation of the central canal during the embryonic stage, residual embryonic epithelial cells remain within the spinal cord parenchyma. These eventually become ischemic, necrotic, and form a cavity (syringomyelia). This condition is often accompanied by basilar impression, Chiari malformation (cerebellar tonsil herniation), scoliosis or kyphoscoliosis, spina bifida, and pes cavus. Some researchers also propose a genetic factor in its etiology.

II. Abnormal Cerebrospinal Fluid Dynamics

Due to a congenital abnormality of the craniocervical junction that prevents cerebrospinal fluid from flowing from the fourth ventricle into the subarachnoid space, the fluid instead enters the central canal of the spinal cord. This eventually causes the central canal to progressively dilate and rupture, forming a syrinx (cavity).

Key Diagnostic Points

Clinically, it is more common in males than in females. Symptoms may begin in childhood or adolescence, but most cases have an onset between 20–30 years of age. After onset, the progression is slow. Clinical symptoms depend on the location of the cavity.

### Location and Extent The following sections describe the clinical manifestations and treatment methods for each region in detail.

Cervicothoracic Syringomyelia

The condition most commonly involves the lower cervical and upper thoracic spinal cord, with an insidious onset. Initially, paresthesia appears in the hands, followed by pain in one or both upper limbs and the chest and back, along with loss of temperature sensation. The sensory loss is distributed in a semi-horseshoe pattern on the upper limbs and a horseshoe pattern on the chest and back. Progressive weakness and atrophy occur in the hand muscles, with the atrophic range gradually extending to the entire upper limb and shoulder girdle muscles. Horner syndrome develops when the ciliospinal center or sympathetic pathway at the C8–T1 segments is disrupted. As the syrinx expands and damages the pyramidal tract, spinothalamic tract, and dorsal column, corresponding motor and sensory symptoms appear. Nutritional disturbances in the upper limbs, as well as scoliosis and kyphosis, are quite common. In advanced stages, sphincter dysfunction may occur. Nutritional disturbances include abnormal sweating in the affected area, thickened or thinned skin, painless ulceration after skin breakdown, hyperkeratosis of the nails, resorption of the phalanges, and even spontaneous detachment of the fingertips, constituting Morvan syndrome. Because the trigeminal sensory tract descends into the cervical spinal cord, loss of pain and temperature sensation may occur in the peripheral parts of the face.

Treatment

1. Acupoints and Needling Techniques

1. **Jianzhen (SI9)**: Located 1 *cun* directly above the posterior axillary crease, directly below Naoshu (SI10). Use a 2-*cun*, 30-gauge filiform needle. After routine disinfection of the local area, insert perpendicularly toward the anterior shoulder approximately 1.8 *cun*. Needling sensation: local distension and pain.

2. **LU2 (Yunmen)**: Located in the anterolateral aspect of the clavicle, 6 cun lateral to the midsternal line, in the depression medial to the coracoid process of the scapula. Use a 30-gauge, 2 cun filiform needle. After routine local disinfection, insert approximately 1.8 cun obliquely toward SI9 (Jianzhen) at the posterior shoulder. Needling sensation: distension and pain in the shoulder, or radiation to the arm and hand.

3. **LI15 (Jianyu)**: Located at the midpoint of the upper portion of the deltoid muscle, between the acromial end of the clavicle, the acromial end of the scapular spine, and the greater tubercle of the humerus. Use a gauge-30, 2-cun filiform needle. After routine local disinfection, insert obliquely toward LI11 (Quchi) to a depth of approximately 1.8 cun. Needling sensation: distension and pain within the deltoid muscle, or a radiating sensation upward.

4. LI11 (Quchi): Located at the midpoint of the line connecting the radial end of the cubital crease and the lateral epicondyle of the humerus. Use a 0.30 mm × 50 mm (No. 30, 2 cun) filiform needle. After routine sterilization of the local area, insert obliquely towards HT3 (Shaohai) to a depth of approximately 1.8 cun. Sensation: local distension and pain.

5. **Waiguan (TE5)**: Located on the dorsal aspect of the forearm, between the radius and ulna, 2 cun proximal to Yangchi (TE4). Use a 30-gauge, 1.5-cun filiform needle. After routine local disinfection, insert perpendicularly to a depth of approximately 1.3 cun. Needling sensation: local distension and soreness, or radiation toward the dorsum of the hand and the middle finger.

6. **LI4 (Hegu)**: Located on the dorsum of the hand, between the 1st and 2nd metacarpal bones, approximately at the midpoint of the radial side of the 2nd metacarpal. Using a 30-gauge, 2 *cun* filiform needle, perform routine local disinfection, then insert approximately 1.8 *cun* toward the SI3 (Houxi) direction. Needle sensation: local distension and pain.

7. ST7 (Xiaguan): With the mouth closed, locate the point in the depression between the zygomatic arch and the mandibular notch. Use a 30-gauge filiform needle, 2 cun in length. Perform routine local disinfection, then insert perpendicularly about 1.6 cun. Needling sensation: local distension and pain.

8. ST4 (Dicang): Located 0.4 cun lateral to the corner of the mouth. A 30-gauge, 2 cun filiform needle is inserted obliquely toward ST6 (Jiache) to a depth of approximately 1.8 cun, following routine local disinfection. Needle sensation: local distension and pain.

9. Taiyang (EX-HN5): Located in the temporal region, in the depression 1 cun posterior to the midpoint between the lateral canthus and the lateral end of the eyebrow. Using a No. 30 gauge, 2 cun filiform needle, insert obliquely toward ST6 (Jiache) to a depth of approximately 1.8 cun. Needling sensation: local distension and soreness.

II. Methods

For unilateral upper limb pain or muscle atrophy, only the ipsilateral acupoints are selected; for bilateral conditions, bilateral acupoints are used simultaneously. If only facial trigeminal nerve sensory dysfunction is present, select either unilateral or bilateral facial points and additionally use the ipsilateral LI4 (Hegu). If both facial and upper limb symptoms are present, points on the face and upper limb can be selected together; for bilateral conditions, bilateral points are used simultaneously. After needle insertion, apply electrical stimulation for 40 minutes before needle removal. Treatment is performed once daily, with 10 sessions constituting one course. A 5-day rest is taken before the next course.

Lumbosacral Syringomyelia

Syringomyelia at this spinal segment is relatively rare. The clinical manifestations include loss of pain and temperature sensation in the lower limbs, feet, perineum, and genitalia, while light touch and deep sensation remain intact. Muscle atrophy of the lower limbs and feet is present, with a prominent nutritional disturbance manifesting as gastrocnemius muscle atrophy. Joint enlargement with crepitus during movement is observed, but without pain.

【Treatment】

I. Acupoints and Needling Methods

1. **Jiaji Point 16 (EX-B2)**: Located 0.5 cun lateral to the spine at the level of the 4th lumbar vertebra. Use a #30 gauge needle.

A 2.5-cun filiform needle was inserted with routine local disinfection toward the gap of the 4th lumbar transverse process to reach the nerve root, eliciting an electric shock–like sensation radiating to the lower limb. Needle sensation: an electric shock–like radiation to the ipsilateral lower limb and foot.

2. GB30 (Huantiao): Located on the lateral lower buttock, at the junction of the lateral one-third and middle one-third of the line connecting the most prominent point of the greater trochanter of the femur and the sacral hiatus. The patient lies in the lateral recumbent position. Use a 30-gauge, 4-cun (100 mm) filiform needle; after routine local disinfection, insert obliquely toward the piriformis muscle within the greater sciatic foramen to a depth of approximately 3.8 cun. Needle sensation: radiating numbness toward the lower limb, sole of the foot, or toward the perineum and anus.

3. **BL37 (Yinmen)**: Located on the line connecting BL36 (Chengfu) and BL40 (Weizhong), 6 cun below BL36 (Chengfu). Using a 30-gauge, 2.5 cun filiform needle, after routine local disinfection, insert perpendicularly approximately 2.3 cun. Needling sensation: distension and pain in the thigh, or a sensation radiating downward to the lower limb and foot.

4. BL40 (Weizhong): Located at the midpoint of the popliteal crease on the posterior aspect of the knee, between the tendons of biceps femoris and semitendinosus. Use a 30-gauge, 2-cun filiform needle. After routine local disinfection, insert perpendicularly to a depth of approximately 1.8 cun. Needling sensation: distension and pain in the popliteal region, or radiating toward the foot.

5. **BL57 (Chengshan)**: Located at the center of the gastrocnemius muscle belly, midway between BL40 (Weizhong) and BL60 (Kunlun). A 30-gauge, 2-cun filiform needle is used. After routine local disinfection, insert perpendicularly toward the anterior tibia to a depth of approximately 1.8 cun. Needling sensation: local distension and pain.

6. **BL60 (Kunlun)**: Located in the depression posterior to the lateral malleolus, between the lateral malleolus and the Achilles tendon. Use a 30-gauge, 1.5-cun filiform needle. After routine sterilization of the local area, insert approximately 1 cun toward the contralateral medial malleolus. Needle sensation: distension and pain in the heel region, possibly radiating to the dorsum of the foot.

2. Methods

The patient is placed in the prone position. The prescribed points are needled according to the standard method and connected to electrical stimulation, with the needles retained for 40 minutes. Upon needle removal, cupping is applied to each point for approximately one minute. This treatment is performed once daily, with 10 sessions constituting one course of treatment, followed by a 5-day rest before the next course.

Syringobulbia

This condition is most often an extension of cervical syringomyelia into the brainstem (syringobulbia), but it can also occur independently. It typically presents as a slit-like, asymmetric lesion that affects only the cranial nerve nuclei or tracts on one side, leading to unilateral paralysis of the vocal cord and soft palate, along with atrophy and fasciculations of the tongue.

Treatment

I. Acupoints and Acupuncture Techniques

1. **Shang Lianquan (Upper Lianquan)**: Located 1 cun above Lianquan (CV23), in the depression below the mandible. Use a 32-gauge, 1.5 cun filiform needle. Perform routine local disinfection and insert perpendicularly upward to a depth of approximately 1 cun. The needling sensation is distension and pain at the root of the tongue.

2. GV15 (Yamen): Located on the posterior midline, 0.5 cun directly above the posterior hairline, in a depression. Use a 30-gauge, 1.5 cun filiform needle. After routine disinfection of the local area, puncture perpendicularly approximately 1 cun. Needling sensation: local distention and pain.

3. Bilateral LI4 (Hegu): Located on the dorsum of the hand, between the 1st and 2nd metacarpal bones, near the midpoint of the radial border of the 2nd metacarpal bone. Use a 30-gauge, 2-cun filiform needle. After routine local disinfection, insert approximately 1.8 cun toward SI3 (Houxi). Needling sensation: local distension and pain.

Methods

The patient takes a seated position. The above acupoints are needled according to the standard method, and electroacupuncture is applied for 40 minutes with needles retained. Treatment is administered once daily, with 10 sessions constituting one course. A 5-day rest is taken before the next course begins.

Commentary

There is currently no specific effective treatment for this condition. Acupuncture treatment for syringomyelia can alleviate various types of pain, restore atrophied muscles, and relieve some of the motor and sensory dysfunction that appears after the onset of the disease, but long-term treatment is required. For patients with limb dysfunction and muscle atrophy, it is recommended that they increase physical exercise during the treatment period to strengthen their constitution, which can help promote early recovery.

Understanding the Pathophysiology and Syringomyelia Causes

Syringomyelia is a chronic, progressive degenerative disorder characterized by the development of a fluid-filled cavity, or syrinx, within the spinal cord parenchyma. The precise pathogenesis remains incompletely elucidated, but the formation of a syrinx is closely linked to disruptions in cerebrospinal fluid (CSF) dynamics. Among the most well-recognized syringomyelia causes is the Chiari type I malformation, where herniation of the cerebellar tonsils obstructs the foramen magnum, altering CSF flow and driving fluid into the spinal cord. Other etiologies include spinal cord trauma, arachnoiditis, intramedullary tumors, and congenital anomalies such as spinal dysraphism. The cavity may extend rostrally into the medulla oblongata, a condition termed syringobulbia, or caudally into the thoracic and lumbar regions. The expansion of the syrinx progressively damages surrounding neural tracts, leading to characteristic neurological deficits. Importantly, the pathophysiological mechanisms—whether related to obstructive CSF flow, pressure gradients, or vascular compromise—determine the pattern of clinical evolution. A thorough understanding of these causal factors is essential for guiding both diagnostic evaluation and therapeutic decision-making, as addressing the underlying etiology remains a cornerstone of management.

Recognizing Syringomyelia Symptoms and Clinical Presentation

The clinical manifestations of syringomyelia reflect the progressive involvement of spinothalamic, corticospinal, and motor neuron pathways within the spinal cord. Classic syringomyelia symptoms include a dissociative sensory loss, wherein pain and temperature sensation are impaired while light touch and proprioception are preserved, owing to early compression of the decussating spinothalamic fibers in the anterior commissure. This typically presents as a capelike distribution over the shoulders, arms, and upper trunk. As the syrinx enlarges, lower motor neuron signs emerge, such as muscle atrophy, weakness, and fasciculations, particularly in the hands and distal upper extremities. Upper motor neuron involvement may manifest later as spasticity and hyperreflexia in the lower limbs. Autonomic dysfunction, including Horner syndrome and bladder disturbances, can also occur. Neurotrophic disturbances, such as painless ulcers and Charcot joints, are characteristic but often late findings. Headache and neck pain are common, especially when associated with Chiari malformation. The insidious onset and slow progression of these symptoms often lead to delayed recognition, underscoring the importance of a high index of clinical suspicion in patients presenting with unexplained sensory or motor deficits.

Advances in Syringomyelia Diagnosis and Imaging

Establishing a definitive syringomyelia diagnosis requires a combination of clinical assessment and advanced neuroimaging. Magnetic resonance imaging (MRI) is the gold standard, offering unparalleled visualization of the syrinx and associated structural abnormalities. The diagnostic workup begins with a detailed neurological examination to document the pattern and extent of sensory, motor, and reflex changes. However, clinical findings alone are insufficient, as they may overlap with other myelopathies. MRI not only confirms the presence of a syrinx but also evaluates its dimensions, location, and relationship to surrounding neural structures. Additionally, MRI can identify causative factors such as Chiari malformation, spinal cord tethering, or post-traumatic changes. In some cases, cine phase-contrast MRI is employed to assess dynamic CSF flow at the craniocervical junction, providing functional information that aids in surgical planning. Early and accurate diagnosis is critical, as delayed intervention may permit irreversible neurological damage. The integration of clinical and imaging data forms the foundation for differentiating syringomyelia from other conditions, such as multiple sclerosis or intramedullary tumors, and for determining the most appropriate management strategy.

Syringomyelia MRI Findings and Their Diagnostic Utility

The hallmark syringomyelia MRI findings include a well-defined, longitudinally oriented cystic cavity within the spinal cord parenchyma, most frequently located in the cervical region. On T1-weighted sequences, the syrinx typically appears hypointense, similar to CSF, while on T2-weighted sequences, it is hyperintense. The presence of septations or loculations within the cavity can give it a beaded or irregular appearance. MRI further reveals the relationship of the syrinx to the central canal and any associated edema or gliosis in the surrounding cord tissue. In cases secondary to Chiari malformation, imaging will demonstrate tonsillar herniation below the foramen magnum, often with crowding of the posterior fossa. Post-traumatic syringomyelia may show an expanded cord with altered signal intensity at the injury site. The utility of MRI extends beyond diagnosis; it is essential for surgical planning, as it allows measurement of syrinx length, diameter, and proximity to the pial surface. Serial MRI studies are also employed to monitor disease progression or regression after intervention. The detailed anatomical information provided by MRI is indispensable for guiding clinical decisions and evaluating treatment efficacy in patients with syringomyelia.