Chronic Pain & Cancer Pain Relief | Dr. Mao Ying (Pain Management) | CMCS Shanghai

About Dr. Mao Ying

Dr. Mao Ying is Chief of Pain Medicine at Huashan Hospital, Fudan University — one of China's foremost pain medicine departments and a national reference centre for neuromodulation therapy, interventional pain management, and multidisciplinary cancer pain treatment. He is a pioneer in multidisciplinary pain treatment in China, recognised for his expertise in spinal cord stimulation, intrathecal drug delivery systems, radiofrequency ablation of visceral nerve plexuses, and the integration of psychological and palliative care into comprehensive pain management programmes. Dr. Mao's practice is defined by the philosophy that pain medicine is not about prescribing more opioids — it is about understanding the neurobiological mechanisms driving each patient's pain and selecting the intervention that addresses those mechanisms most precisely, with the minimum pharmacological burden and the maximum functional restoration. His department at Huashan Hospital has established one of China's most comprehensive pain medicine programmes, integrating CT-guided interventional procedures, neuromodulation implantation, psychological pain therapy, and palliative care coordination into a unified pathway for patients with complex chronic and cancer pain.

Case Overview

Mr. Robert Sinclair, a 62-year-old British retired teacher based in Shanghai, presented one year after Whipple pancreaticoduodenectomy for pancreatic ductal adenocarcinoma with a six-month history of severe refractory upper abdominal and lumbar pain — VAS 8–9 at rest — that had failed to respond adequately to oral morphine sustained-release 120 mg daily, gabapentin, and pregabalin, and had produced only three days of relief from a celiac plexus block performed at another institution. The pain had rendered him unable to lie flat, caused severe insomnia, and was associated with profound anxiety and depression (HADS anxiety 18, depression 16). CT and MRI confirmed tumour recurrence with encasement of the coeliac axis and superior mesenteric artery root and invasion of the retroperitoneal nerve plexus — the anatomical substrate of his refractory visceral neuropathic pain.

Dr. Mao Ying led a multidisciplinary team including oncology, psychology, and palliative care to design a combined neuromodulation strategy: CT-guided water-cooled radiofrequency ablation (V-RFA) of the coeliac plexus to destroy the peripheral visceral afferent pathway, followed by spinal cord stimulation (SCS) implantation at T5–T8 to modulate the central sensitisation and sympathetically maintained pain component. Following V-RFA, VAS fell from 9 to 4. Following SCS trial stimulation at 10 kHz, VAS fell to 1–2 with the patient describing the pain as replaced by a comfortable paraesthesia-free sensation. Morphine was reduced by 50% in the first week and discontinued completely at one month. At three months, VAS was 0–1 at rest, sleep quality had normalised (PSQI from 18 to 5), and HADS scores had fallen to 7 for both anxiety and depression.

Patient Background

• Name / Nationality: Mr. Robert Sinclair (pseudonym) — British; retired secondary school teacher based in Shanghai; one year post Whipple pancreaticoduodenectomy for pancreatic ductal adenocarcinoma
• Age / Sex: 62-year-old male
• Chief Complaint: Severe upper abdominal burning pain with lumbar electric shock-like radiation for 6 months; worsening for 1 week; VAS 8–9 at rest
• Pain characteristics: Constant burning epigastric pain; electric shock-like radiation to the lumbar region; unable to lie supine; severe insomnia; pain-related immobility
• Prior pain treatment: Oral morphine sustained-release 120 mg daily (high dose); gabapentin and pregabalin (inadequate response); celiac plexus block at another institution (3 days of partial relief only)
• Opioid side effects: Severe constipation requiring daily laxatives; nausea and vomiting; daytime somnolence; cognitive dulling
• Psychological assessment: HADS anxiety score 18 (severe); HADS depression score 16 (severe); pain catastrophising scale elevated
• Examination: Distressed appearance; well-healed abdominal surgical scar; deep epigastric tenderness without rebound; mild bilateral lower limb oedema

Diagnostic Workup and Pain Mechanism Analysis

Imaging

• Contrast-enhanced CT and MRI (abdomen): Post-Whipple recurrence confirmed; tumour encasing the coeliac axis and superior mesenteric artery root; retroperitoneal nerve plexus invasion; no resectable disease
• PET-CT: High local metabolic activity at the tumour recurrence site; no distant bone metastasis — pain is not attributable to osseous metastatic disease

Pain Mechanism Analysis — Dr. Mao's Framework

Dr. Mao Ying's ward round analysis identified three concurrent pain mechanisms driving the patient's refractory pain syndrome — each requiring a different therapeutic target:

• Nociceptive pain component: Tumour infiltration of retroperitoneal tissue and visceral capsule — activating peripheral nociceptors through mechanical distension and inflammatory mediator release; partially responsive to opioids but generating the burning quality of the epigastric pain
• Neuropathic pain component (dominant): Tumour invasion of the coeliac plexus and greater splanchnic nerves — generating ectopic neural discharge, central sensitisation, and sympathetically maintained pain (SMP); characterised by the electric shock-like radiation to the lumbar region and the allodynia; poorly responsive to opioids; the primary driver of treatment failure
• Opioid-induced hyperalgesia (OIH): Long-term high-dose opioid therapy had paradoxically increased pain sensitivity through central sensitisation mechanisms — meaning that increasing the morphine dose was not only ineffective but was actively worsening the pain; opioid dose reduction, not escalation, was required

Dr. Mao's diagnostic assessment: This patient is not undertreated with opioids. He is overtreated with opioids and undertreated for the actual mechanism of his pain. The dominant mechanism is neuropathic — the tumour has invaded the coeliac plexus and the greater splanchnic nerves, and those nerves are firing continuously. Morphine does not stop nerves from firing. It reduces the cortical perception of the signal, but at the doses this patient is taking, it has induced hyperalgesia — the opioid itself is now amplifying the pain signal. The correct treatment is to destroy the peripheral pathway with radiofrequency ablation and to modulate the central sensitisation with spinal cord stimulation. The morphine needs to come down, not go up.

Multidisciplinary Team Discussion and Treatment Strategy

The MDT convened by Dr. Mao Ying included pain medicine, oncology, psychology, and palliative care. The consensus was that conventional pharmacological escalation had reached its ceiling — further opioid dose increases would increase side effects without meaningfully improving pain control — and that a combined neuromodulation strategy was indicated.

Treatment goals: Reduce VAS to below 3 at rest; reduce opioid dose by at least 50%; restore sleep quality; improve psychological wellbeing; enable mobilisation and social participation.

Selected strategy: Two-stage combined approach — CT-guided water-cooled radiofrequency ablation of the coeliac plexus (V-RFA) to address the peripheral visceral neuropathic component, followed by spinal cord stimulation (SCS) implantation to address the central sensitisation and sympathetically maintained pain component. This peripheral destruction plus central modulation combination is the signature approach of Huashan Hospital's Pain Medicine Department for refractory visceral cancer pain.

Psychological intervention: Concurrent referral to the pain psychology team for cognitive behavioural therapy targeting pain catastrophising and sleep hygiene — initiated in parallel with the interventional procedures.

Operative Procedure

Stage 1 — CT-Guided Water-Cooled Coeliac Plexus Radiofrequency Ablation (V-RFA)

Positioning: Prone position on the CT table; intravenous sedation and local anaesthesia.

CT guidance: Real-time CT fluoroscopy used to guide bilateral paravertebral needle placement at the T12–L1 level — the anatomical level of the coeliac ganglia. The retrocrural approach was selected to access the coeliac plexus anterior to the aorta while avoiding the tumour mass and the major vascular structures.

Diagnostic block: Before radiofrequency ablation, 5 mL of 2% lidocaine was injected bilaterally at the coeliac ganglion level. VAS fell from 9 to 4 within 10 minutes — confirming that the coeliac plexus was the primary peripheral pain generator and that ablation at this site would be therapeutically effective. A reduction of greater than 50% is the threshold for proceeding to ablation.

Water-cooled radiofrequency ablation: Water-cooled radiofrequency electrodes were positioned at the confirmed coeliac ganglion locations bilaterally. The water-cooling system circulates chilled water through the electrode tip during ablation — preventing charring at the electrode-tissue interface and allowing higher energy delivery to create a larger spherical ablation zone than conventional radiofrequency. Ablation parameters: 65 degrees Celsius, 120 seconds per site, bilateral. The larger ablation zone is critical for coeliac plexus ablation because the plexus is a diffuse network of ganglia and nerve fibres rather than a discrete anatomical structure — conventional radiofrequency creates a small elliptical lesion that may miss portions of the plexus, explaining the short duration of relief from the patient's prior conventional block.

Post-procedure assessment: Immediate VAS reduction from 9 to 4; the burning epigastric component was significantly reduced; the electric shock-like lumbar radiation persisted — confirming that the central sensitisation component required separate treatment with SCS.

Dr. Mao's procedural note: The water-cooled electrode is the key difference from the conventional radiofrequency that was done at the other hospital. Conventional radiofrequency creates a lesion of 8 to 10 millimetres in diameter. Water-cooled radiofrequency creates a lesion of 15 to 20 millimetres. For a diffuse structure like the coeliac plexus, that difference is the difference between partial ablation and complete ablation. The prior block gave three days of relief because it was a local anaesthetic block — temporary by design. The prior radiofrequency, if it was performed, likely created a lesion that was too small to ablate the entire plexus. Our ablation covered the entire coeliac ganglion region bilaterally. The burning pain is gone. The electric pain in the back is the central component — that is what the SCS will address.

Stage 2 — Spinal Cord Stimulation (SCS) Trial Implantation

Timing: Three days after V-RFA — before the expected partial pain rebound as the local anaesthetic component of the ablation procedure dissipated, allowing accurate assessment of the SCS effect against the residual neuropathic pain baseline.

Epidural access: T9–T10 interlaminar epidural puncture under fluoroscopic guidance; 8-contact percutaneous lead advanced to the T5–T8 level under fluoroscopic visualisation. The T5–T8 dorsal column position was selected based on the patient's pain distribution — upper abdominal and lumbar — which maps to the T5–T8 dermatomes and the visceral afferent pathways entering the spinal cord at these levels.

10 kHz high-frequency stimulation: The trial stimulator was programmed to 10 kHz frequency, 30 microsecond pulse width, amplitude titrated to patient comfort. At 10 kHz, spinal cord stimulation produces analgesia without the paraesthesia (tingling sensation) that characterises conventional low-frequency SCS — the so-called paraesthesia-free or subthreshold stimulation. The patient reported: The pain has been replaced by something — not a tingling, just a comfortable feeling where the pain was. The burning is gone. The electric shocks in my back are gone. VAS fell to 1–2 within 30 minutes of stimulation onset.

Trial period: External pulse generator connected; patient discharged with the trial system for a seven-day home assessment period. Pain diary, VAS scores, sleep quality, and opioid consumption recorded daily. At seven days: VAS consistently 1–2; morphine dose self-reduced by the patient from 120 mg to 60 mg daily; sleep duration increased from 2–3 hours to 6–7 hours per night; patient able to walk 500 metres without pain exacerbation.

Trial success criteria met: Greater than 50% pain reduction, greater than 50% opioid reduction, patient satisfaction high — proceeding to permanent implantation.

Stage 3 — Permanent SCS Implantation (IPG)

Lead anchoring: The trial lead was anchored to the thoracic fascia at the T9–T10 entry point under local anaesthesia and sedation.

IPG implantation: Rechargeable implantable pulse generator placed in a subcutaneous pocket in the right flank — rechargeable IPG selected to avoid battery replacement surgery for a minimum of 10 years.

Final parameters: 10 kHz frequency, 30 microsecond pulse width, 3.0 V amplitude — providing continuous paraesthesia-free analgesia without any subjective stimulation sensation.

Operative data (combined stages): Total procedural time approximately 150 minutes across both stages; blood loss less than 10 mL; no neurological complications; no infection.

Post-operative Management and Outcomes

Opioid Reduction Protocol

• Week 1 post-SCS implantation: Morphine sustained-release reduced from 120 mg to 60 mg daily (50% reduction); gabapentin tapered and discontinued; no withdrawal symptoms — the SCS analgesia prevented the pain rebound that typically accompanies opioid reduction
• Month 1: Morphine completely discontinued; low-dose NSAID (celecoxib) continued for residual inflammatory pain component; no opioid requirement
• Opioid side effect resolution: Constipation resolved within one week of opioid reduction; nausea and somnolence resolved within two weeks; cognitive clarity improved significantly

Three-Month Follow-up Outcomes

• Pain scores: VAS 0–1 at rest; VAS 2–3 with physical activity — clinically significant improvement from baseline VAS 8–9
• Sleep quality: PSQI (Pittsburgh Sleep Quality Index) improved from 18 (severely impaired) to 5 (normal) — sleep duration 7–8 hours per night
• Functional status: Able to walk independently; resumed limited social activities; no longer confined to bed
• Psychological status: HADS anxiety score reduced from 18 to 7 (mild); HADS depression score reduced from 16 to 7 (mild); pain catastrophising scale normalised
• Oncological status: Tumour markers stable; no significant disease progression on imaging; patient living with disease in a controlled pain state
• Opioid status: Zero opioid consumption; no opioid craving or withdrawal

Expert Commentary — Dr. Mao Ying

1. Opioid-Induced Hyperalgesia: When More Morphine Makes the Pain Worse

The most important and most frequently missed diagnosis in refractory cancer pain management is opioid-induced hyperalgesia. OIH occurs when prolonged high-dose opioid therapy paradoxically increases pain sensitivity through central sensitisation mechanisms — upregulation of NMDA receptors, activation of descending facilitation pathways, and neuroinflammatory changes in the dorsal horn. The clinical signature of OIH is pain that worsens despite opioid dose escalation, spreads beyond the original pain territory, and is accompanied by allodynia and hyperalgesia. In this patient, the morphine dose had been escalated to 120 mg daily without meaningful pain improvement — the classic OIH pattern. The correct response to OIH is not further dose escalation. It is opioid rotation or reduction, combined with a non-opioid analgesic strategy that addresses the central sensitisation directly. Spinal cord stimulation is uniquely effective in OIH because it activates the endogenous descending inhibitory pathways that opioids have suppressed — restoring the brain's own pain control mechanisms rather than substituting an exogenous pharmacological suppressor. In this case, SCS allowed complete opioid cessation without pain rebound — the definitive demonstration that the opioids were not controlling the pain but were contributing to it.

2. Water-Cooled Radiofrequency Ablation: Larger Lesions for a Diffuse Target

The coeliac plexus is not a discrete anatomical structure — it is a diffuse network of ganglia and nerve fibres distributed around the coeliac axis and superior mesenteric artery over an area of several centimetres. Conventional radiofrequency ablation creates a lesion of 8 to 10 mm in diameter — sufficient to ablate a discrete nerve but inadequate to ablate a diffuse plexus. This is why conventional coeliac plexus blocks and conventional radiofrequency procedures produce short-lived relief: they ablate a portion of the plexus but leave the remainder intact to regenerate and resume pain signalling. Water-cooled radiofrequency addresses this limitation by creating a lesion of 15 to 20 mm in diameter — large enough to encompass the entire coeliac ganglion region bilaterally. The water-cooling mechanism prevents charring at the electrode tip, which would otherwise limit energy delivery and lesion size. The result is a more complete and more durable ablation of the visceral afferent pathway — explaining why V-RFA produces longer-lasting relief than conventional techniques in pancreatic cancer pain. At Huashan Hospital, V-RFA has replaced conventional coeliac plexus neurolysis as our standard interventional approach for refractory pancreatic cancer visceral pain.

3. 10 kHz Spinal Cord Stimulation: Paraesthesia-Free Analgesia for Cancer Pain

Conventional spinal cord stimulation operates at frequencies of 40 to 100 Hz and produces analgesia through the gate control mechanism — activating large-diameter dorsal column fibres that inhibit pain signal transmission in the dorsal horn. The clinical experience of conventional SCS is a tingling paraesthesia that overlaps the pain territory — the patient feels the stimulation replacing the pain. High-frequency SCS at 10 kHz produces analgesia through a different mechanism — believed to involve direct inhibition of dorsal horn interneurons and modulation of descending inhibitory pathways — without generating any subjective paraesthesia sensation. The patient feels nothing from the stimulator; they simply notice that the pain is gone. This paraesthesia-free quality is particularly important for cancer pain patients, who are often already experiencing abnormal sensations from neuropathic pain and do not benefit from the addition of stimulation-induced paraesthesia. The 10 kHz modality also provides more consistent analgesia with changes in body position — critical for a patient who needs to move from lying to sitting to walking without pain breakthrough. In our cancer pain programme, 10 kHz SCS has become the preferred modality for visceral neuropathic pain with central sensitisation.

4. Whole-Person Pain Management: The Bidirectional Brain-Pain Relationship

Pain is not a peripheral signal that the brain passively receives — it is a brain-generated experience that is profoundly modulated by psychological state, sleep quality, social connection, and meaning. In this patient, the severe anxiety and depression were not consequences of the pain — they were amplifiers of it. The brain in a state of severe anxiety generates a pain signal that is disproportionate to the peripheral input, because the descending inhibitory pathways that normally suppress pain are suppressed by the anxiety itself. Treating the pain without treating the anxiety produces incomplete analgesia. Treating the anxiety without treating the pain produces incomplete psychological recovery. The bidirectional relationship means that both must be treated simultaneously. In this case, the SCS reduced the pain, which reduced the anxiety, which further reduced the pain — a virtuous cycle that replaced the vicious cycle of pain amplifying anxiety amplifying pain. The psychological intervention accelerated this cycle by providing cognitive tools to interrupt catastrophising and restore sleep hygiene. At Huashan Hospital, every patient in our pain programme receives a psychological assessment and concurrent psychological support — not as an adjunct to the real treatment, but as an integral component of it.

How CMCS Shanghai Coordinated This Case

CMCS Shanghai supported Mr. Sinclair and his family from initial pain crisis presentation through three-month follow-up, including: urgent coordination of pain medicine consultation with Dr. Mao Ying at Huashan Hospital with same-week appointment scheduling; bilingual review of all prior pain treatment records, imaging reports, and opioid prescription history with clinical summary for the MDT; coordination of contrast-enhanced CT, MRI, and PET-CT with bilingual radiology report translation and pain mechanism interpretation; bilingual interpretation throughout all MDT discussions involving pain medicine, oncology, psychology, and palliative care; coordination of the CT-guided V-RFA procedure including pre-procedure fasting instructions, sedation consent, and post-procedure monitoring in English; real-time updates to the patient's wife and his GP in Edinburgh during both procedural stages; SCS trial period support including pain diary coordination, daily bilingual check-ins, and VAS score tracking communicated to Dr. Mao's team; permanent IPG implantation coordination including surgical consent, device programming session interpretation, and recharging instruction in English; opioid reduction protocol support including pharmacy coordination for morphine tapering schedule and withdrawal monitoring; psychology referral coordination with bilingual cognitive behavioural therapy sessions; three-month follow-up coordination including VAS assessment, PSQI, HADS, and imaging with results communicated to the patient's oncologist and GP in the United Kingdom; and establishment of a long-term pain management protocol with SCS parameter optimisation scheduling and direct liaison between Dr. Mao's team and the patient's palliative care physician in Edinburgh.

For international patients with refractory cancer pain, chronic neuropathic pain, or complex pain syndromes requiring advanced interventional pain management in Shanghai, Dr. Mao Ying's team at Huashan Hospital represents pain medicine expertise at the international frontier — combining water-cooled radiofrequency ablation, 10 kHz spinal cord stimulation, and comprehensive psychological pain therapy to achieve opioid-sparing analgesia and functional restoration in patients for whom conventional pharmacological treatment has failed. CMCS ensures that expertise is accessible: in the patient's language, with overseas physicians and palliative care teams informed at every step, from the first pain assessment through long-term neuromodulation management.

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.