Scoliosis & Disc Herniation | Dr. Yang Changwei (Spine Surgery) | CMCS Shanghai

About Dr. Yang Changwei

Dr. Yang Changwei is a Senior Spine Surgeon at Changzheng Hospital, Naval Medical University — one of China's highest-volume spine surgery centres and a national reference institution for complex spinal deformity correction, lumbar disc disease, and cervical spine disorders. He is a recognised leader in adolescent idiopathic scoliosis correction, posterior osteotomy techniques, and the integration of intraoperative navigation and neuromonitoring into complex spinal reconstruction. Dr. Yang's practice is defined by the philosophy that spinal deformity surgery must simultaneously achieve three goals: maximum curve correction, complete neurological protection, and preservation of the maximum number of functional motion segments — because a 16-year-old patient will live with the consequences of every surgical decision for the next six decades. His department at Changzheng Hospital has established one of China's most comprehensive spinal deformity programmes, integrating 3D-printed pre-operative planning models, O-arm intraoperative navigation, multimodal intraoperative neurophysiological monitoring, and Enhanced Recovery After Surgery protocols into a unified surgical pathway for patients with complex spinal pathology.

Case Overview

Ms. Sophie Brennan, a 16-year-old Irish student based in Shanghai, presented with a five-year history of progressive spinal deformity and a three-month history of left lower limb radicular pain and left great toe extensor weakness. Standing full-spine radiographs demonstrated a Lenke 5C thoracolumbar curve with a primary Cobb angle of 58 degrees at T11–L3 and a compensatory thoracic curve of 35 degrees at T5–T10. Lumbar MRI revealed a large sequestrated L4–L5 disc herniation with free nuclear fragment compressing the left L5 nerve root — a concurrent pathology that fundamentally altered the surgical strategy. Risser sign Grade IV confirmed near-skeletal maturity, indicating that the curve was unlikely to progress further with conservative management and that surgical correction was required.

Dr. Yang Changwei designed a single-stage posterior procedure combining L4–L5 discectomy and transforaminal lumbar interbody fusion (TLIF) for the disc herniation with T10–L4 pedicle screw fixation and Ponte osteotomy at L1–L3 for the scoliosis correction — addressing both pathologies through a single posterior incision, avoiding a second anaesthetic and a second recovery. O-arm navigation guided pedicle screw placement throughout. Multimodal intraoperative neurophysiological monitoring (IONM) with motor evoked potentials (MEP) and somatosensory evoked potentials (SEP) provided continuous neurological surveillance — and proved critical when MEP amplitude fell to 50% of baseline during osteotomy closure, prompting immediate intervention that prevented neurological injury. Total operative time was 240 minutes; blood loss 400 mL with 300 mL autologous cell salvage. Post-operative radiographs confirmed correction of the primary curve from 58 to 12 degrees — an 80% correction rate. Left lower limb radicular pain resolved on post-operative day one; great toe extensor power recovered to Grade IV. The patient was discharged on day five and returned to school at three months.

Patient Background

• Name / Nationality: Ms. Sophie Brennan (pseudonym) — Irish; secondary school student based in Shanghai; high academic and athletic demands; strong quality-of-life and cosmetic priorities
• Age / Sex: 16-year-old female; Risser sign Grade IV — near-skeletal maturity
• Chief Complaint: Progressive spinal deformity noticed by parents 5 years ago; worsening over the past 6 months with visible rib hump; left lower limb radicular pain and left great toe extensor weakness for 3 months
• Deformity history: Unequal shoulder height first noted at age 11; no brace treatment initiated; progressive worsening with adolescent growth spurt; razor-back deformity (rib hump) now visible on forward bending
• Neurological symptoms: Continuous low back pain radiating to the posterolateral left thigh and leg; left great toe dorsiflexion weakness; no bladder or bowel dysfunction
• Examination: Right thoracolumbar scoliosis visible on standing; Adam forward bending test positive with prominent right rib hump; left straight leg raise positive; left great toe extensor power Grade III; left Achilles tendon reflex reduced

Imaging Assessment

Standing Full-Spine Radiographs

• Primary curve (thoracolumbar): T11–L3 right thoracolumbar curve; Cobb angle 58 degrees — severe scoliosis by definition (above 40 degrees); rigid curve with limited flexibility on bending films
• Compensatory curve (thoracic): T5–T10 left thoracic curve; Cobb angle 35 degrees — structural compensatory curve; Lenke 5C classification
• Coronal balance: C7 plumb line displaced approximately 2 cm from the central sacral vertical line — trunk imbalance present
• Risser sign: Grade IV — iliac apophysis ossification nearly complete; skeletal maturity approaching; curve progression risk reduced but correction potential limited compared with younger patients; rigid internal fixation required
• Lenke classification: Type 5C — thoracolumbar/lumbar primary curve, non-structural thoracic compensatory curve, lumbar modifier C (significant lumbar curve deviation)

Lumbar MRI

• L4–L5 disc: Large sequestrated disc herniation — free nuclear fragment within the spinal canal, migrated inferiorly; compressing the left L5 nerve root against the posterior vertebral body; no containment by the posterior longitudinal ligament
• Left L5 nerve root: Significant compression with perineural oedema — consistent with the clinical findings of left L5 radiculopathy (great toe extensor weakness, lateral leg pain)
• Conus medullaris: Normal position; no Chiari malformation, no syringomyelia — neurogenic scoliosis excluded; confirms idiopathic aetiology
• Significance of concurrent pathology: The sequestrated disc herniation is not incidental — it is an active neurological emergency requiring surgical decompression. Its presence in the context of scoliosis correction creates a critical surgical planning challenge: scoliosis correction alters spinal alignment and may worsen nerve root tension if the disc herniation is not addressed simultaneously

CT Three-Dimensional Reconstruction

• Precise delineation of pedicle morphology at each instrumented level — critical for pre-operative screw trajectory planning in a rotated, deformed spine where standard anatomical landmarks are unreliable
• 3D-printed model fabricated from CT data for pre-operative surgical simulation and screw path rehearsal

Dr. Yang's pre-operative assessment: The MRI changes everything about how we approach this case. Without the disc herniation, this is a straightforward Lenke 5C correction — challenging, but well within our standard protocol. With the disc herniation, we have two problems that interact with each other. If we correct the scoliosis first and leave the disc, the change in spinal alignment will alter the tension on the L5 nerve root in an unpredictable direction — it might improve, or it might worsen. We cannot accept that uncertainty in a 16-year-old with active neurological deficit. So we address both in the same operation. The TLIF gives us the disc removal and the nerve root decompression. The Ponte osteotomy gives us the curve correction. One incision, one anaesthetic, one recovery. That is the correct strategy.

Pre-operative Planning and Surgical Strategy

The MDT discussion led by Dr. Yang Changwei established the diagnosis of adolescent idiopathic scoliosis (Lenke 5C) with concurrent L4–L5 sequestrated disc herniation causing left L5 radiculopathy. The surgical strategy was designed around four principles: complete nerve root decompression before curve correction; maximum curve correction using osteotomy rather than distraction alone; preservation of motion segments above the fusion construct; and continuous neurological surveillance throughout the procedure.

Surgical plan: Single-stage posterior approach combining L4–L5 TLIF (discectomy, nerve root decompression, interbody cage, and posterior fusion) with T10–L4 pedicle screw instrumentation and Ponte osteotomy at L1–L3 for three-dimensional curve correction.

Rationale for Ponte osteotomy over distraction alone: A 58-degree rigid thoracolumbar curve cannot be adequately corrected by rod distraction alone without generating excessive tensile forces on the spinal cord and nerve roots. Ponte osteotomy — resection of the bilateral facet joints and portions of the laminae at the apex of the curve — releases the posterior spinal column, allowing the curve to be corrected by posterior shortening (compression on the concave side and derotation) rather than anterior lengthening. This mechanism reduces spinal cord tension during correction and achieves superior three-dimensional correction compared with distraction-based techniques alone.

Navigation and monitoring platform: O-arm intraoperative CT navigation for pedicle screw placement; multimodal IONM with continuous MEP and SEP monitoring; 3D-printed pre-operative model for screw trajectory rehearsal; wake-up test protocol on standby.

Operative Procedure

Anaesthesia and Positioning

Anaesthesia: General anaesthesia with endotracheal intubation. Total intravenous anaesthesia (TIVA) protocol — avoiding volatile anaesthetic agents that suppress MEP amplitude and reduce the sensitivity of intraoperative neurological monitoring. Neuromuscular blockade used only for intubation and reversed before IONM baseline recording.

Positioning: Prone on a Jackson spinal surgery table with the abdomen free — abdominal decompression reduces epidural venous pressure and intraoperative blood loss. Careful padding of all pressure points; eyes protected; arms positioned to avoid brachial plexus stretch.

Cell salvage: Intraoperative autologous blood salvage system activated from the start of the procedure — targeting return of shed blood to avoid allogeneic transfusion in a 16-year-old patient.

Phase 1 — Exposure and O-arm Navigation-Guided Pedicle Screw Placement

Exposure: Posterior midline incision from T10 to L4; subperiosteal dissection of paraspinal muscles bilaterally to expose the posterior elements from T10 to L4. The rotational deformity of the thoracolumbar curve significantly distorts the normal anatomical relationships of the pedicle entry points — standard freehand technique based on surface landmarks carries an unacceptable screw malposition rate in this setting.

O-arm navigation: Intraoperative O-arm CT scan acquired after positioning and exposure; image data registered to the patient's anatomy in real time. Navigation probe used to identify the precise pedicle entry point and trajectory at each level — providing three-dimensional guidance that accounts for the rotational deformity of each vertebra individually. Pedicle screws placed at T10, T11, T12, L1, L2, L3, and L4 bilaterally under continuous navigation guidance.

Navigation accuracy: Post-placement O-arm scan confirmed all screws within the pedicle cortex with no medial, lateral, or inferior wall breach. Total screw placement time approximately 40 minutes; blood loss during this phase less than 50 mL.

Dr. Yang's operative note: In a rotated thoracolumbar spine, the pedicle entry point can be displaced by 10 to 15 millimetres from its expected position based on surface landmarks. A medially misplaced screw in the thoracolumbar region can injure the spinal cord or nerve roots. A laterally misplaced screw provides inadequate purchase and will fail under the corrective forces we apply during derotation. The navigation system eliminates this uncertainty. We see the pedicle in three dimensions, we plan the trajectory before we make the first hole, and we confirm the position before we commit to the screw. In a 16-year-old patient who will carry these screws for sixty years, that accuracy is not optional.

Phase 2 — L4–L5 Discectomy, Nerve Root Decompression, and TLIF

L4–L5 laminotomy: Partial laminotomy at L4–L5 under operating microscope magnification; ligamentum flavum excised to expose the epidural space and the compressed left L5 nerve root.

Nerve root decompression: The sequestrated disc fragment — a firm, gelatinous mass of nuclear material — was identified compressing the left L5 nerve root against the posterior vertebral body. The fragment was carefully dissected free from the nerve root and removed in its entirety. The nerve root was probed proximally and distally to confirm complete decompression; no residual compression identified.

Disc space preparation and cage insertion (TLIF): The L4–L5 disc space was entered through the right-sided transforaminal approach; remaining disc material removed; endplates prepared to bleeding bone. A PEEK interbody cage packed with autologous bone graft was inserted into the disc space under fluoroscopic guidance — restoring disc height, providing anterior column support, and creating the conditions for solid interbody fusion.

Posterior bone graft: Local bone from the laminotomy and facetectomy was morselised and placed posterolaterally at L4–L5 to supplement the interbody fusion.

Phase 3 — Ponte Osteotomy and Three-Dimensional Curve Correction

Ponte osteotomy at L1–L3: Bilateral facetectomy (complete resection of the superior and inferior articular processes) and partial laminectomy at L1, L2, and L3 — releasing the posterior spinal column at the apex of the thoracolumbar curve. This posterior column release converts the rigid curve into a flexible deformity that can be corrected by rod contouring and compression without generating excessive tensile forces on the anterior spinal cord.

Rod insertion and concave-side compression: Pre-contoured titanium rods inserted bilaterally. The concave (left) rod was connected first and compressed — closing the Ponte osteotomy gaps on the concave side and initiating coronal plane correction.

Convex-side derotation: The convex (right) rod was then used to apply derotational force — rotating the apical vertebrae from their pathological rotated position toward the neutral position. Derotation corrects the rotational component of the scoliosis that is responsible for the rib hump deformity and the three-dimensional trunk imbalance.

IONM alert — critical intervention: During osteotomy gap closure and derotation, MEP amplitude in the left lower limb fell to 50% of baseline — the threshold for mandatory surgical pause per IONM protocol. Dr. Yang immediately halted all corrective manoeuvres. Intravenous methylprednisolone was administered to reduce spinal cord oedema; mean arterial pressure was raised to above 85 mmHg through vasopressor support to optimise spinal cord perfusion. The surgical team waited ten minutes without further manipulation. MEP amplitude recovered to above 80% of baseline — the threshold for safe continuation. The corrective manoeuvres were resumed at a slower pace with continuous monitoring.

Dr. Yang's IONM note: The MEP drop to 50% is the signal we train for and hope never to see. When it happens, the correct response is immediate and non-negotiable: stop everything, protect the cord, and wait. The instinct to continue — to finish the correction, to close the osteotomy — must be completely suppressed. The cord is telling you it is under stress. You listen to the cord. The methylprednisolone reduces oedema. The blood pressure support maintains perfusion. And then you wait. In this case, ten minutes was enough. The amplitude came back. We continued. But if it had not come back, we would have reversed the correction, closed the wound, and brought the patient back for a staged procedure. A partial correction with intact neurology is infinitely better than a complete correction with paraplegia.

Final correction and rod locking: With MEP amplitude stable above 80%, the corrective manoeuvres were completed; all screw-rod connections locked; final O-arm scan confirmed screw positions unchanged and osteotomy gaps appropriately closed.

Operative data: Total operative time 240 minutes; total blood loss approximately 400 mL; autologous cell salvage returned 300 mL; no allogeneic blood transfusion required.

Post-operative Outcomes and ERAS

Radiographic Outcomes

• Primary curve (T11–L3): Cobb angle corrected from 58 degrees to 12 degrees — correction rate 79%; excellent result by international benchmarks (correction rate above 70% considered excellent for rigid thoracolumbar curves)
• Compensatory thoracic curve: Spontaneous correction from 35 degrees to 18 degrees — expected auto-correction of the non-structural compensatory curve following primary curve correction
• Coronal balance: C7 plumb line returned to within 1 cm of the central sacral vertical line — trunk balance restored
• Instrumentation: All screws confirmed within pedicle cortex; no screw pullout, no rod fracture; cage position at L4–L5 confirmed satisfactory on CT

Neurological Outcomes

• Post-operative day 1: Left lower limb radicular pain completely resolved; left great toe extensor power improved from Grade III to Grade IV
• No new neurological deficit: No motor or sensory deficit attributable to the scoliosis correction; the IONM-guided intervention during the MEP alert prevented neurological injury
• No cerebrospinal fluid leak, no deep wound infection

ERAS Milestones

• 6 hours post-operatively: Mobilised to standing with thoracolumbosacral orthosis (TLSO) brace support and physiotherapy assistance
• Post-operative day 3: Wound drains removed; drain output below threshold
• Post-operative day 5: Discharged home with TLSO brace; community physiotherapy arranged
• 3-month follow-up: Returned to full-time school attendance; no restriction on non-contact physical activity; TLSO brace discontinued; radiographs confirmed maintained correction with no loss of Cobb angle

Expert Commentary — Dr. Yang Changwei

1. Ponte Osteotomy: Posterior Shortening as the Mechanism of Safe Correction

The fundamental biomechanical principle of scoliosis correction is that the spine can be straightened by shortening the convex side, lengthening the concave side, or both. Distraction-based correction — lengthening the concave side — generates tensile forces on the spinal cord and nerve roots that increase with the degree of correction. In a rigid 58-degree curve, the tensile forces required for adequate correction by distraction alone approach the threshold for spinal cord injury. Ponte osteotomy changes the mechanism: by resecting the posterior elements at the curve apex, we release the posterior column and allow correction to occur by posterior shortening — compression on the concave side closes the osteotomy gaps while the anterior column acts as the hinge. The spinal cord is not lengthened; it is gently repositioned as the vertebrae rotate toward neutral. This is why Ponte osteotomy achieves superior correction rates with lower neurological risk compared with distraction alone in rigid thoracolumbar curves. It is not a more aggressive operation — it is a more intelligent one.

2. Intraoperative Neurophysiological Monitoring: The Non-Negotiable Safety Standard

Intraoperative neurophysiological monitoring is not a precaution in complex scoliosis surgery — it is the standard of care. The risk of neurological injury during scoliosis correction is real and irreversible: a patient who wakes from surgery with paraplegia cannot be made whole by any subsequent intervention. MEP monitoring detects motor pathway compromise in real time — before the injury becomes permanent — by measuring the electrical response of the lower limb muscles to transcranial motor cortex stimulation. A 50% amplitude reduction is the universally accepted alert threshold: it indicates that the motor pathway is under sufficient stress to warrant immediate intervention. In this case, the alert occurred during osteotomy closure — the moment of maximum mechanical stress on the spinal cord. The response — immediate cessation of all corrective manoeuvres, pharmacological neuroprotection, and blood pressure optimisation — is a protocol, not a judgment call. The protocol exists because the judgment call, made under surgical pressure with incomplete information, is too often wrong. At Changzheng Hospital, multimodal IONM with both MEP and SEP is mandatory for all complex spinal deformity corrections. The wake-up test remains available as a confirmatory tool if IONM signals are equivocal, but it has not been required in our programme since the introduction of continuous multimodal monitoring.

3. Single-Stage Combined Surgery: Eliminating the Second Anaesthetic

The decision to address the L4–L5 disc herniation and the scoliosis in a single operative session is not primarily about surgical efficiency — it is about patient safety and oncological logic. Staged surgery — disc surgery first, scoliosis correction second — exposes the patient to two general anaesthetics, two recovery periods, two infection risks, and two periods of post-operative pain. More importantly, it creates a clinical dilemma: after disc surgery, the scoliosis correction will alter the spinal alignment and potentially change the tension on the decompressed nerve root in an unpredictable direction. By performing the TLIF first within the same operative session — decompressing the nerve root under direct vision before any corrective forces are applied — we eliminate this uncertainty. The nerve root is free before the correction begins. The IONM monitors its function throughout the correction. The single-stage approach is more demanding technically, but it is the correct approach for a patient with concurrent active neurological deficit and progressive spinal deformity.

4. Motion Segment Preservation in Adolescent Spinal Surgery

Every lumbar motion segment that is fused in a 16-year-old patient will be absent for the next sixty years. The adjacent segments above and below the fusion construct will compensate by moving more — increasing the mechanical stress on their discs and facet joints and accelerating their degeneration. This is adjacent segment disease, and it is the most important long-term complication of spinal fusion in young patients. The surgical strategy must therefore minimise the fusion length while achieving adequate curve correction and neurological decompression. In this case, the fusion extends from T10 to L4 — the minimum construct length required to correct the Lenke 5C curve and include the TLIF at L4–L5. The L5–S1 segment is preserved — the most important lumbar motion segment for load transfer and sagittal balance. The Ponte osteotomy at L1–L3 achieves the correction without extending the fusion to L5 or S1. Every decision about fusion length in adolescent spinal surgery must be made with the patient's sixty-year functional trajectory in mind, not just the immediate radiographic result.

How CMCS Shanghai Coordinated This Case

CMCS Shanghai supported Ms. Brennan and her family from initial presentation through three-month post-operative follow-up, including: urgent coordination of standing full-spine radiographs, lumbar MRI, and CT three-dimensional reconstruction with same-week scheduling and bilingual radiology report translation; specialist referral to Dr. Yang Changwei at Changzheng Hospital's Department of Spine Surgery with priority consultation scheduling; coordination of pre-operative 3D-printed spinal model fabrication for surgical planning; bilingual interpretation throughout all surgical planning discussions, anaesthetic assessment, and informed consent sessions covering the risks of neurological injury, blood transfusion, and adjacent segment disease; real-time surgical updates to the patient's parents during the 240-minute procedure, including explanation of the IONM alert and the intervention taken; post-operative daily bilingual updates covering neurological recovery, drain output, mobilisation progress, and discharge planning; coordination of TLSO brace fitting and physiotherapy referral before discharge; three-month follow-up radiograph coordination with Cobb angle measurement and results communicated to the patient's orthopaedic surgeon in Ireland; school re-entry planning support including medical documentation in English for the school administration; and establishment of a long-term surveillance protocol for adjacent segment monitoring with annual radiographic follow-up.

For international patients with adolescent idiopathic scoliosis, adult spinal deformity, lumbar disc disease, or complex spinal pathology requiring expert surgical evaluation in Shanghai, Dr. Yang Changwei's team at Changzheng Hospital represents spinal surgical expertise at the international frontier — combining O-arm navigation precision, multimodal intraoperative neurophysiological monitoring, and single-stage combined surgery to achieve maximum curve correction and complete neurological protection in patients who will live with the results for decades. CMCS ensures that expertise is accessible: in the patient's language, with overseas physicians and families informed at every step, from the first standing radiograph through long-term spinal surveillance.

This case report is de-identified and published for educational purposes. All clinical details have been anonymized in accordance with patient privacy standards. CMCS Shanghai is a medical concierge service and does not provide direct medical care.