Functional Neurosurgery · Trainee Resources
Ablative Neurosurgery for Cancer Pain
Cordotomy, Mesencephalotomy, Myelotomy, and DREZ
A practical guide to the destructive procedures that remain the right answer for selected patients with medically refractory, malignant pain
Orientation
Ablative pain surgery is, for most trainees, the part of functional neurosurgery they will read about but rarely see. The widespread availability of oral and intrathecal opioids has made these destructive procedures uncommon, and an entire generation of neurosurgeons has been trained without watching a cordotomy. Yet for a specific and recognizable patient — medically refractory, unilateral, nociceptive pain from cancer, with a limited life expectancy — a lesion can abolish pain in a single afternoon, restore a clear sensorium by allowing opioids to be tapered, and return a dying patient to their family. The skill worth preserving is not just the technique; it is recognizing the patient.
This reading is built around one organizing principle: the procedure follows the pain. The level of the pain on the body, and whether it is somatic, visceral, or deafferentation in quality, points to a specific target. A pearl learned in the operating rooms where these procedures are still performed anchors the whole framework — pain below the shoulder can be reached by cordotomy, but pain above roughly the C4 dermatome, in the head, neck, or face, lies beyond the reach of a spinal procedure and must be addressed higher in the neuraxis, at the midbrain or the trigeminal nucleus. Get the level and the modality right, and the operation works. Get them wrong, and no amount of technical skill will help.
Choosing the Patient and the Target
1.The Two Questions That Determine the Operation
Every ablative pain decision reduces to two questions asked in order. First, where is the pain on the body? Second, what is the quality of the pain — somatic, visceral, or deafferentation? The answers map onto distinct anatomical pathways, and each pathway has its own lesion.
Somatic nociceptive pain travels the spinothalamic tract. After primary afferents enter the cord ipsilateral to the pain and synapse in the dorsal horn, second-order axons cross the anterior commissure and ascend in the contralateral anterolateral cord — the substrate a cordotomy interrupts. Visceral pain from pelvic and abdominal structures travels instead in a discrete midline dorsal-column pathway, which is why a tiny midline lesion (punctate myelotomy) can relieve visceral pain that a cordotomy would miss. Deafferentation pain — from nerve root avulsion, postherpetic injury, or Pancoast invasion of the plexus — arises from disinhibited dorsal-horn neurons and responds not to interrupting an ascending tract but to ablating the generator itself at the dorsal root entry zone.
2.Why Malignancy and Life Expectancy Matter
Ablative procedures were largely abandoned for benign pain for a sound reason: their benefit is not permanent, and they can generate new pain. The analgesia of a cordotomy tends to wear off over months to a few years, and a minority of patients develop a new deafferentation neuropathic pain after the lesion. In a patient with decades of life ahead, those liabilities are disqualifying. In a patient with cancer and a life expectancy under a year, they rarely have time to manifest — the benefit outlasts the patient. This is the central logic of modern ablative pain surgery, and it is why the strongest indication is medically refractory, unilateral, nociceptive pain of malignant origin with limited prognosis.
"Medically refractory" deserves a working definition. Pain is refractory when the patient continues to suffer despite appropriate escalation, or when the dose required for relief produces intolerable side effects — sedation, delirium, opioid toxicity — or when adequate analgesia can only be sustained in hospital, eroding the quality of whatever time remains. Each of those is a reason to consider a procedure, and each is a reminder that the goal is not merely a lower pain score but a patient who is both comfortable and lucid.
Percutaneous Cervical Cordotomy
3.The Ideal Candidate
Percutaneous cervical cordotomy interrupts the spinothalamic tract at the C1–C2 level, producing contralateral loss of pain and temperature sensation below roughly the C4–C5 dermatome. The ideal candidate has medically refractory, unilateral, nociceptive pain from cancer, below the shoulder, with a life expectancy under a year. Pain that crosses the midline will not be fully covered by a unilateral lesion, and a unilateral procedure does nothing for the ipsilateral side. Classic indications are the relentless unilateral pain of mesothelioma, Pancoast tumor, and bony metastatic disease of one hemipelvis or limb.
Two qualifications refine the "nociceptive" requirement. Pain from tumor compressing a nerve is still nociceptive in the sense that matters here and responds well, even though it might loosely be called neuropathic. True deafferentation pain, by contrast, originates higher in the neuraxis and should not be expected to respond. And visceral pain has its own pathway and its own operation, discussed below.
4.Contraindications and the Respiratory Caveat
The candidate must be able to lie supine and hold still for roughly 60 minutes and, critically, to provide reliable feedback during physiological testing — the lesion is titrated against the patient's awake responses. Dementia or delirium is therefore a contraindication; a language barrier is not, provided a translator can be used and reliable responses confirmed preoperatively. Because the cord is punctured, coagulopathy or thrombocytopenia is disqualifying, and an intracranial mass that could herniate with CSF egress is a contraindication.
5.Technique and Physiological Confirmation
The modern procedure is CT-guided. With the patient supine in the scanner under local anesthesia and monitored sedation, contrast is introduced into the cervical thecal sac to outline the cord, and a fine radiofrequency electrode is advanced through the lateral neck into the anterolateral cord contralateral to the pain, with impedance monitoring distinguishing CSF from cord. Physiological confirmation is the heart of the operation. Macrostimulation at high frequency (on the order of 50 Hz) should evoke a sensation of warmth, pain, or temperature in the painful region of the contralateral body, confirming proximity to the spinothalamic tract. Low-frequency stimulation (around 2 Hz) should not provoke ipsilateral muscle contraction; if it does, the electrode is too close to the corticospinal tract and must be repositioned. Only then is the radiofrequency lesion made, incrementally, until the target body region can no longer distinguish sharp from dull.
Why somatotopy matters. The spinothalamic tract is not a homogeneous bundle — its fibers are arranged in an orderly map, and knowing that map is what lets the surgeon tailor the lesion to the patient's pain rather than simply analgesing the whole hemibody. The tract is built up sequentially from caudal to rostral: fibers entering at lower (sacral, then lumbar, then thoracic) levels cross and are pushed progressively aside as fibers from higher levels join above them. The result is a lamination in which the lower-body (sacral/leg) fibers lie more superficially and posterolaterally in the anterolateral quadrant, while the upper-body (arm and neck) fibers lie deeper and more anteromedially, layered against the fibers already present from below. In simple terms, leg is superficial and lateral; arm is deep and anterior.
This has direct operative consequences. To capture lower-limb pain the electrode need only reach the superficial, posterolateral edge of the tract; to capture upper-limb or upper-trunk pain the lesion must extend deeper and more anteriorly. A modern in vivo study mapping awake stimulation responses against simultaneous CT confirmed exactly this arrangement and offered a practical rule: an ideal cord entry point for either territory lies roughly halfway between the equator and the anterior pole of the cord, with the lesion then enlarged as needed to recruit lower-limb fibers — all while staying clear of the corticospinal tract, which sits just anterior. Because the leg fibers form a smaller, compact, superficial group, leg analgesia is generally the more reliably achieved; reaching arm fibers without straying into the motor tract is the more demanding target, which is why awake stimulation mapping of each lesion is so valuable.
Step 1 — Stimulation, to confirm position (parameters in volts, as with the Codman/Cosman-type RF generators in common use). Sensory stimulation at 50 Hz, pulse width 1 ms, at low voltage (concordant response typically appearing around 0.01–0.1 V) should evoke warmth, cool, or pain that the patient localizes to the painful contralateral hemibody — confirming the tip is in the spinothalamic tract. Motor stimulation at 2 Hz, 1 ms, raised to about 1 V, should produce no contraction; a twitch (on the ipsilateral, electrode side) below that ceiling means the electrode is too close to the corticospinal tract and must be repositioned before lesioning.
Step 2 — Lesioning. Once impedance, concordant sensory localization, and the absence of motor contraction are all confirmed, the radiofrequency lesion is made and titrated incrementally, re-checking the clinical effect and the contralateral sensory exam between lesions. Two RF approaches are equivalent: the published CT-guided cordotomy series used current-controlled lesioning (on the order of 20–40 mA for ~60 s, increased as needed), while a temperature-controlled approach (starting around 60 °C and stepping up by a few degrees, ~60 s per lesion) achieves the same graded effect — use whichever mode your generator and practice favor. After each lesion the contralateral body is examined for the desired sensory change — loss of pinprick, temperature (tested with ice), and the sharp/dull distinction over the painful region, while light touch is relatively preserved — titrating to adequate analgesia in the target territory.
6.Perioperative Care
Preoperative. These patients are typically admitted before surgery rather than done as outpatients, because the perioperative pain and medication management is itself the work. Use the admission to optimize and document the baseline pain and opioid regimen, confirm the pain is unilateral and below C4–C5 and that the contralateral lung/diaphragm can tolerate the procedure, correct coagulopathy/thrombocytopenia, and confirm the patient can cooperate with awake testing. A practical maneuver is to convert the patient to a short-acting intravenous opioid infusion (e.g., fentanyl) beforehand: because cordotomy relief is immediate, a short-half-life agent lets the team taper rapidly and safely in the hours after the lesion, rather than chasing a long-acting regimen down. Counsel the patient and family that the pain may be gone the same day and that opioids will then be reduced deliberately.
Outcomes and postoperative care. Pain relief after cordotomy is immediate and often dramatic. Contemporary series report a sharp fall in pain scores on the first postoperative day and opioid reductions on the order of 75% within a week, with the majority of palliative patients able to leave hospital. Because relief is instantaneous, the most important postoperative task is opioid titration: the regular dose is typically cut substantially (commonly by half) immediately after surgery and then reduced further as tolerated. The hazard to anticipate is not under-treatment but over-rapid weaning — tapering too quickly precipitates withdrawal, even as the pain itself is gone. A frequently observed and welcome secondary effect is the return of mental clarity once the opioid burden lifts, which families and teams should be prepared for as part of end-of-life care.
Pain Above the Shoulder: Mesencephalotomy
7.The Pearl: When Pain Climbs Above C4
This is the hinge of the whole framework. A cordotomy cannot safely relieve pain in the head, neck, or face, because the spinothalamic fibers serving those regions lie too high — to reach them in the cord would require a lesion at a level that threatens respiration and upper-limb motor function. The pain pathway must instead be interrupted higher, where it runs near an approachable surface. The point at which the spinothalamic (and trigeminothalamic) pathway lies closest to a stereotactically reachable target is the midbrain. Interrupting it there is mesencephalotomy.
8.Target, Technique, and the Lesion's Evolution
The history of mesencephalotomy is instructive because it explains where the target sits today. Early open sections of the midbrain spinothalamic tract relieved pain but frequently injured the adjacent medial lemniscus, producing dense numbness and disabling dysesthesia — sometimes leaving the patient worse than before. The stereotactic era allowed the lesion to be placed with precision, and awake physiological mapping revealed something unexpected: pain relief did not require destroying the spinothalamic tract itself. A lesion placed more medially, engaging the multisynaptic reticular (spinoreticulothalamic) pathways while sparing the lemniscus, gave durable relief with far less sensory loss and dysesthesia. The target came "full circle" — the modern target is not the spinothalamic tract but a more medial reticular zone that deliberately spares it. This is the key conceptual shift, and it is why mesencephalotomy can relieve pain while producing little measurable change in pinprick or temperature sensation.
Targeting. The classical coordinates, referenced to the intercommissural line, lie approximately 5 mm behind the posterior commissure, 5–10 mm lateral to the midline, and 5 mm below the intercommissural plane, at the level of the inferior colliculus rather than the superior colliculus to reduce oculomotor injury. A modern MR-based semidirect approach refines this by referencing structures adjacent to the target rather than the distant commissures: the vertical coordinate at the midpoint between the superior and inferior colliculi, the anteroposterior coordinate at the level of the aqueduct, and the lateral coordinate chosen by which tract is intended — roughly 5 mm lateral to the aqueduct for the spinoreticulothalamic tract, 6.5 mm for the trigeminothalamic, and 8 mm for the neospinothalamic tract, reflecting their progressively more lateral position in the midbrain. An alternative lateral landmark used by some groups places the target at about 6 mm, defined as halfway between the lateral edge of the aqueduct and the lateral border of the midbrain. A typical RF lesion of ~4 mm diameter then encompasses the chosen pathway.
Which tract for which patient. The choice of lateral coordinate is dictated by the type and location of pain. Predominantly neuropathic or mixed pain is directed at the medial spinoreticulothalamic pathway (5 mm), which is the default and most frequently used target — consistent with the principle that the reticular zone, not the classical spinothalamic tract, gives durable relief with least sensory loss. Predominantly nociceptive pain is directed at the discriminative pathways by somatotopy: the trigeminothalamic tract (6.5 mm) for facial pain, and the neospinothalamic tract (8 mm) for body or limb pain. For mixed pain, two confluent lesions are made in the same sitting — the reticulothalamic target plus the relevant trigemino- or neospinothalamic target — which is also why the more conservative 70 °C setting is favored when two targets are ablated.
Stimulation and the warning responses. The neighborhood is what makes awake macrostimulation (commonly tested at 25 and 100 Hz, 0.1–2.0 V) so important — each undesirable response localizes a specific adjacent structure and dictates a specific electrode move:
- Extraocular movement / diplopia → too high (near the oculomotor nuclei/fibers) — move the electrode downward, or reposition ~1.5–2 mm laterally.
- Fear, panic, or anguish → too medial, into the periaqueductal (central) grey, whose stimulation characteristically evokes intense fear and autonomic change — reposition ~1.5–2 mm laterally.
- Tinnitus → lateral lemniscus / inferior colliculus (auditory pathway) — reposition superiorly/medially.
- Contralateral paresthesia → medial lemniscus (the structure whose injury produces the dreaded dysesthesia) — move ~1.5–2 mm posteriorly/medially.
- Contralateral heat in the hemibody or hemiface → the spinothalamic/trigeminothalamic tract itself (too lateral for the reticular target).
How the correct spot is recognized intraoperatively. Because the goal is the reticular zone and not the STT, there is often little or no analgesia to pinprick to confirm placement — so the operation is steered by stimulation responses, not by sensory loss. The desired reticular target most commonly produces central heat or moderate discomfort referred to the core of the body (rather than a discrete contralateral limb) with a muted affective response, while none of the warning responses above are provoked at amplitudes up to ~1.5 V. A test lesion (e.g., 50 °C for ~40 s) is made first to check for untoward effects, then a permanent lesion at 70–75 °C for ~60 s — the higher temperature reduces recurrence at the cost of slightly more risk. Some surgeons add microelectrode recording, and intraoperative somatosensory evoked potentials (SEPs) can help monitor proximity to the medial lemniscus.
9.Laterality, Suffering, and Side Selection
Mesencephalotomy carries an instructive lesson about the affective dimension of pain, and it has a laterality logic quite different from cordotomy. Because the medial reticular target projects bilaterally to the thalamus and feeds limbic structures, a unilateral lesion frequently produces bilateral pain relief, and it can blunt the suffering component of pain as much as the sensation itself — particularly valuable in extensive head and neck cancer where emotional distress is inseparable from the physical pain.
Choosing the side. The lesion is placed contralateral to the pain. For predominantly one-sided pain, lesion the side opposite the worst pain; for midline or bilateral pain, make a single lesion contralateral to the more severe side first and reassess, since the bilateral reticular projection means one lesion often helps both sides, with a contralateral lesion staged later only if needed.
Patient selection — what does best. Outcomes track strongly with pain location and type. In contemporary series, face, cervicobrachial, and upper-limb pain respond significantly better than trunk pain, and trunk pain does worst — both the lowest relief and the highest recurrence. The anatomical reason is instructive: the neospinothalamic fibers serving the trunk are a tiny contingent at the midbrain (the trunk is sparsely innervated and these fibers shed collaterals as they ascend), so there is simply less to interrupt. Predominantly neuropathic pain also does less well and recurs more often than nociceptive pain. The practical reading: mesencephalotomy is at its best for refractory head, neck, face, and upper-limb cancer pain, and should be offered cautiously for trunk-predominant or purely neuropathic pain.
What to expect postoperatively: immediate relief that may span both sides, typically with little measurable sensory loss; watch specifically for transient diplopia/gaze problems (oculomotor proximity) and for dysesthesia (lemniscal). Contemporary MR-guided semidirect-targeting series report excellent or good relief in roughly 85% at 3 months and 75% at a year, with low morbidity — comparable efficacy to the historical series at much lower complication rates, which is why the operation is considered underused rather than obsolete.
A lower-risk alternative. For selected patients — especially where the oculomotor and dysesthesia risks of the midbrain target are unacceptable — a medial thalamic lesion (intralaminar / centromedian–parafascicular or basal thalamotomy) targets the same multisynaptic medial pain system one relay higher, and is reported to give comparable relief with less risk. It is a reasonable substitute when the suffering/affective component dominates, and some surgeons prefer it outright.
Two More Tools: Myelotomy and DREZ
10.Punctate Midline Myelotomy for Visceral Pain
Visceral pain from inextirpable abdominal and pelvic malignancy — the diffuse, midline, hard-to-localize pain of advanced colorectal, gynecologic, or pancreatic disease — does not travel primarily in the spinothalamic tract and is poorly served by cordotomy. It ascends instead in a discrete midline (postsynaptic) dorsal-column visceral pathway. A small midline lesion of the dorsal columns interrupts this pathway and can produce substantial relief with remarkably little neurological morbidity, given how small the lesion is. It is an underused option precisely because the pathway it targets was recognized comparatively recently, and it deserves a place in the surgeon's mental map of visceral cancer pain.
From commissural to limited myelotomy. The term has narrowed over a century. The original commissural myelotomy — a long sagittal cut along the midline, described by Greenfield and performed by Armour in the 1920s — was conceived to divide the decussating spinothalamic fibers across many segments and was correspondingly morbid. The modern operation is the opposite in spirit: a limited or punctate midline myelotomy that selectively disrupts the ascending midline visceral pathway at a single level, sparing almost everything around it. The discovery of the discrete postsynaptic dorsal-column pathway is what made this minimalism rational — a tiny lesion at the right spot does the work the old extended cut was trying to accomplish.
How it is done. The patient is positioned prone and the cord exposed by a small laminectomy. The lesion is placed in the exact midline of the dorsal columns, interrupting the medial roughly 1 mm on either side of the midline to a depth of about 5 mm, which captures the juxtamidline postsynaptic visceral fibers while sparing the more lateral dorsal columns that carry somatic proprioception. Several instruments achieve the same end: a fine radiofrequency electrode, the point of a fine (e.g., 16-gauge) needle used as a microknife — no standard scalpel blade is narrow enough — or fine jeweler's forceps inserted to depth, the variants reported across the punctate and limited-open series. The level is set above the involved viscera: roughly T3–T4 for upper-abdominal (e.g., pancreatic/gastric) pain and T6–T8 (down to ~T10) for lower-abdominal and pelvic/perineal pain. Figures are representative; confirm level and depth against current technique and intraoperative imaging.
11.DREZ Lesioning for Deafferentation Pain
The dorsal root entry zone (DREZ) procedure addresses pain of a fundamentally different mechanism. When a dorsal root is avulsed or destroyed — brachial plexus avulsion, the plexus invasion of a Pancoast tumor, or postherpetic injury — the deafferented second-order neurons in the dorsal horn become hyperactive and generate pain that no ascending-tract interruption will reach, because the generator is the dorsal horn. DREZ lesioning destroys that hyperactive zone directly, along the dorsolateral sulcus, by microsurgical or radiofrequency technique. It is the classical and effective answer to deafferentation pain from root avulsion, with good relief reported in a substantial majority of well-selected patients, and it is the right tool for the specific cancer-pain scenario of plexus deafferentation where cordotomy would fail.
How it is done. After laminectomy exposes the affected segments and the dorsolateral sulcus, lesions are made into the dorsal horn. In the radiofrequency (Nashold) technique a fine thermocouple electrode — a 0.25 × 2 mm tip — is inserted to a depth of about 2 mm, angled roughly 25–35° from the sagittal plane into the sulcus, and heated to about 75 °C for ~15 s per lesion, placed as a serial row at ~1–1.5 mm intervals over the deafferented segments. The microsurgical (Sindou) variant instead makes a sharp ventrolateral incision into the DREZ. As with the nucleus caudalis operation, the hazard is the neighborhood — the corticospinal tract ventrally and the dorsal columns medially — so depth and angle control are everything. Figures are representative; confirm against current technique.
Targeting the Pituitary: SRS Hypophysectomy
12.Stereotactic Radiosurgery Hypophysectomy
One ablative option does not interrupt a pain pathway at all, and it is the right answer for a pattern none of the procedures above handle well: diffuse, multifocal, often bilateral pain, classically from widespread hormone-sensitive bony metastatic disease (breast, prostate). For these patients a focal lesion of a single tract or root is futile — the pain is everywhere. Ablating the pituitary relieves it.
Origins and mechanism. The technique began as surgical or chemical (alcohol) hypophysectomy — "pituitary neuroadenolysis" — performed to regress hormone-sensitive metastatic cancer, where it was noted to produce a striking and often immediate analgesic effect independent of tumor response. The analgesia is incompletely understood but appears to involve hypothalamic–pituitary modulation and redistribution of neuropeptides (oxytocin, vasopressin) rather than simple endocrine ablation, and relief can be rapid and broad, including in non-hormone-dependent tumors.
The modern version. Stereotactic radiosurgery has revived the approach as a minimally invasive, incisionless SRS hypophysectomy: a high single dose delivered to the pituitary gland. Across the historical and modern experience a large majority of treated patients (on the order of ~85%) obtain meaningful pain relief, with complications — chiefly hormonal disturbance and diabetes insipidus — markedly reduced compared with the open and chemical eras while efficacy has been maintained. It is best understood as a palliative tool for the refractory, diffusely painful patient in whom systemic opioids have failed or become intolerable and a pathway-directed lesion cannot cover the pain; optimal dose and patient-selection criteria are still being defined.
| Procedure | Pain pattern | Pathway / target | Signature caveat |
|---|---|---|---|
| Percutaneous cordotomy | Unilateral somatic, below C4–C5 | Spinothalamic tract, C1–C2 anterolateral cord | Ondine's curse if contralateral lung/diaphragm compromised |
| Mesencephalotomy | Head, neck, upper limb (above C4) | Midbrain; ~5 mm behind PC, 5–10 mm lateral, 5 mm below ICL, inferior-colliculus level | Oculomotor injury; lemniscal dysesthesia |
| Punctate midline myelotomy | Midline visceral, pelvic/abdominal | Midline dorsal-column visceral pathway | Often low-thoracic level; small lesion, low morbidity |
| DREZ lesioning | Deafferentation / root avulsion | Dorsal horn at the dorsolateral sulcus | For the deafferented generator, not an ascending tract |
| SRS hypophysectomy | Diffuse / multifocal, often bilateral (hormone-sensitive bony mets) | Pituitary gland (single high SRS dose) | Hormonal disturbance, diabetes insipidus; mechanism not pathway-based |
Pearls
- The procedure follows the pain: fix the level and the quality of the pain first, and the target chooses itself.
- Pain below the shoulder → cordotomy. Pain above C4 (head, neck, face) → mesencephalotomy or a trigeminal-nucleus procedure — this is the single most useful dividing line in ablative pain surgery.
- The strongest indication is medically refractory, unilateral, nociceptive cancer pain with life expectancy under a year — short prognosis is what makes a non-permanent, occasionally pain-generating lesion the right choice.
- Cordotomy is done contralateral to the painful hemibody; motor side effects fall on the ipsilateral (electrode) side — both facts drive side selection and the reading of intraoperative testing.
- Cordotomy demands an awake, cooperative patient: 50 Hz sensory stimulation (concordant response ~0.01–0.1 V) confirms the spinothalamic target; 2 Hz motor stimulation to ~1 V must produce no twitch, or reposition.
- Admit cordotomy patients pre-op and convert to a short-acting IV opioid infusion — relief is immediate, so a short-half-life agent lets you taper rapidly afterward.
- Know the contralateral lung and diaphragm before any cordotomy — Ondine's curse is the lesion's most feared complication and the reason bilateral high cervical lesions are avoided.
- After cordotomy, the postoperative job is opioid titration: cut the dose substantially but not so fast that you precipitate withdrawal in a now pain-free patient.
- Mesencephalotomy's modern target is the medial reticular zone, not the spinothalamic tract — so it is steered by stimulation responses (central-body sensation, no fear/diplopia/contralateral-limb sensation), not by sensory loss, and relief is often bilateral from a unilateral lesion.
- Mesencephalotomy works best for face, cervicobrachial, and upper-limb cancer pain; trunk-predominant and purely neuropathic pain do worst and recur most (the trunk's neospinothalamic representation at the midbrain is tiny) — select accordingly.
- Intralaminar/basal (medial) thalamotomy is a lower-risk alternative to the midbrain target for selected patients, especially when the affective component dominates.
- Don't forget the specialized tools: punctate midline myelotomy (midline cut/RF, ~5 mm deep, level set above the pain — T3–4 upper abdomen, T6–T10 pelvis) for visceral pain, after celiac/splanchnic neurolysis; and DREZ (75 °C/15 s, ~2 mm deep, ~1 mm intervals) for deafferentation/avulsion pain.
- For diffuse, multifocal, often bilateral pain from hormone-sensitive bony metastases, SRS hypophysectomy relieves pain by a non-pathway mechanism — the right tool when no single lesion can cover the pain.
- Atypical facial pain is unlikely to benefit from any ablative procedure — select for a clear nociceptive or deafferentation mechanism, not an ill-defined sensory distortion.
Selected References
- Honey CR, Yeomans W, Isaacs A, Honey CM. The dying art of percutaneous cordotomy in Canada. J Palliat Med. 2014;17(5):624–628. The ideal candidate and the above-C4 pearl, from a contemporary palliative series.
- Honey CM, Ivanishvili Z, Honey CR, Heran MKS. Somatotopic organization of the human spinothalamic tract: in vivo CT-guided mapping in awake patients undergoing cordotomy. J Neurosurg Spine. 2019;30(5):722–728. Modern in vivo somatotopy and the ideal cord entry point.
- Kanpolat Y, Ugur HC, Ayten M, Elhan AH. Computed tomography-guided percutaneous cordotomy for intractable pain in malignancy. Neurosurgery. 2009;64(3 Suppl):ons187–ons194. The reference technique for CT-guided cordotomy.
- Nauta HJW, Soukup VM, Fabian RH, et al. Punctate midline myelotomy for the relief of visceral cancer pain. J Neurosurg. 2000;92(2 Suppl):125–130. The midline dorsal-column visceral pathway and its lesion.
- Gildenberg PL. Mesencephalotomy. In: Lozano AM, Gildenberg PL, Tasker RR, eds. Textbook of Stereotactic and Functional Neurosurgery. 2nd ed. Berlin: Springer; 2009. The definitive chapter on target evolution, coordinates, and complications.
- Almeida T, Monaco BA, Vasconcelos F, Piedade GS, Morell A, Ogobuiro I, Lepski GA, Furlanetti LL, Cordeiro KK, Benjamin C, Jagid JR, Cordeiro JG. Everything old is new again. Revisiting hypophysectomy for the treatment of refractory cancer-related pain: a systematic review. Neurosurg Rev. 2024;47(1):111. Systematic review of pituitary ablation, including SRS hypophysectomy, for refractory cancer pain.
- Marques RAS, Alencar HS, Bannach MA, Vilela-Filho O. Semidirect targeting-based stereotactic mesencephalotomy for the treatment of refractory pain: a case series. J Neurosurg. 2022;136(4):1128–1138. Modern MR-guided mesencephalotomy: tract-specific lateral coordinates, stimulation responses, side selection, and outcomes by pain location.
- Vedantam A, Koyyalagunta D, Bruel BM, et al. Limited midline myelotomy for intractable visceral pain: surgical techniques and outcomes. Neurosurgery. 2018;83(4):783–789. Contemporary midline myelotomy technique and level selection.
- Amano K, Kawamura H, Tanikawa T, et al. Long-term follow-up study of rostral mesencephalic reticulotomy for pain relief — report of 34 cases. Appl Neurophysiol. 1986;49(1–2):105–111. Long-term outcomes for the medial reticular target.
- Sindou M, Mertens P. Microsurgical DREZotomy (MDT) for pain, spasticity, and hyperactive bladder: a 20-year experience. Acta Neurochir (Wien). 1995;137(1–2):1–5. The foundational DREZotomy experience, including cancer/Pancoast deafferentation pain.
- Kanpolat Y, et al. DREZotomy in the treatment of cancer pain: a review. Stereotact Funct Neurosurg. 2012;90(6):356–362. Focused review of DREZ lesioning for cancer-related deafferentation pain.