Phenol neurolysis for severe chronic nonmalignant pain: is the old also obsolete?

Erector Spinae Plane Block (ESPB) as an Alternative for Celiac Plexus Blocks: Expanding ESPB Indications for Mesenteric Ischemia Relief

Mesenteric ischemia is a severe condition associated with abdominal pain which often requires multimodal analgesia, including opioids or sympathetic blocks such as celiac plexus blocks. The erector spinae plane (ESPB) has emerged as a potentially effective alternative for managing pain in various surgical and non-surgical conditions. This case report explores the use of ultrasound-guided ESPB as a novel approach to pain management in a patient with acute on chronic mesenteric ischemia. A 70-year-old male with a history of mesenteric ischemia and multiple comorbidities presented with worsening diffuse abdominal pain. Despite medical and surgical treatment, the patient required a high dose of opioids for pain control. Bilateral ESPBs with continuous infusions were performed at the T6 level under ultrasound guidance. The patient reported immediate and complete relief from abdominal pain following the block, with a significant drop in the pain score. The use of opioids was significantly reduced. This case report demonstrates the potential benefits of ultrasound-guided ESPB as an alternative to traditional pain management techniques in patients with mesenteric ischemia. ESPB may provide safe, simple, and effective analgesia, reducing the need for high-dose opioids and their associated side effects. Further studies are warranted to validate these findings and explore the broader application of ESPB in the management of mesenteric ischemia pain.

Genicular nerve and fracture site chemical neurolysis for distal femoral fracture: a case report

BACKGROUND

Distal femur fractures account for approximately 3%-6% of all femoral fractures. Non-operative management may be an attractive option for the elderly with significant perioperative mortality risk. Adequate pain control is a major barrier to non-operative fracture management. Chemical neurolysis has been described for analgesic management of proximal hip fractures, however no description of interventional management of distal femur fracture exists in literature. We describe a case of phenol chemical neurolysis of genicular nerves in addition to injection at the site of fracture to provide effective analgesia for distal femur fracture.

CASE PRESENTATION

A patient in their 90s with a witnessed mechanical fall sustained an intra-articular displaced fracture of the distal right femur shaft with extension into the distal femoral condyle. The patient elected to undergo non-surgical management given the high perioperative mortality risk. Acute pain service was involved and multimodal oral analgesics including opioids were insufficient in managing the patient's pain. The addition of femoral nerve catheter local anesthetic infusion did not sufficiently improve analgesia. Phenol chemical neurolysis of the superolateral, superomedial, inferomedial genicular nerves and of the fracture site was offered and performed. Resting pain decreased from Numerical Rating Scale 5/10 to 0/10 on postprocedure day 1. This was sustained at the 2-month timepoint.

CONCLUSIONS

We report the successful use of phenol neurolysis of genicular nerves and the fracture site in an elderly patient with a conservatively managed distal femur fracture. These interventions resulted in improved analgesia and achieved prolonged duration of effect.

Neurotoxins subvert the allosteric activation mechanism of SARM1 to induce neuronal loss

SARM1 is an inducible TIR-domain NAD+ hydrolase that mediates pathological axon degeneration. SARM1 is activated by an increased ratio of NMN to NAD+, which competes for binding to an allosteric activating site. When NMN binds, the TIR domain is released from autoinhibition, activating its NAD+ hydrolase activity. The discovery of this allosteric activating site led us to hypothesize that other NAD+-related metabolites might activate SARM1. Here, we show the nicotinamide analog 3-acetylpyridine (3-AP), first identified as a neurotoxin in the 1940s, is converted to 3-APMN, which activates SARM1 and induces SARM1-dependent NAD+ depletion, axon degeneration, and neuronal death. In mice, systemic treatment with 3-AP causes rapid SARM1-dependent death, while local application to the peripheral nerve induces SARM1-dependent axon degeneration. We identify 2-aminopyridine as another SARM1-dependent neurotoxin. These findings identify SARM1 as a candidate mediator of environmental neurotoxicity and suggest that SARM1 agonists could be developed into selective agents for neurolytic therapy.

Palliative Nerve Block for Penile Calciphylaxis: A Case Report on Ultrasound-Guided Phenol Neurolysis

A 78-year-old man with uncontrolled diabetes, heart failure, and hemodialysis-dependent end-stage renal disease presented with intractable penile pain secondary to calciphylaxis and necrosis of his glans penis. Given pain refractory to pharmacologic management and refusal of surgery, treatment entailed an ultrasound-guided dorsal penile nerve block with 5 mL of aqueous 4% phenol bilaterally. The patient reported immediate relief and died pain-free 3 months later. While phenol nerve blocks are increasingly uncommon due to local tissue toxicity, the precision of ultrasound leverages phenol's denaturing and axonal demyelinating properties to facilitate long-term targeted neurolysis to palliate chronic nonmalignant pain.

Novel Conservative Approach to High Surgical Risk Frail Proximal Femur Fractures

One of the major impacts following a neck of femur fracture is pain. Most patients (nearly all) undergo an operation. This usually includes the frailest terminal patients and deemed a palliative procedure to reduce ongoing pain. The operation comes with risks and can reduce life expectancy in these patients and result in prolonged hospital admission, delirium, and postoperative complications. This case highlights a novel approach to managing the frailest end-of-life patients that does not require them to undergo a conventional operation. The case resulted in a quick discharge from hospital and for the patient and family to maximise the time out of hospital, with a reduced analgesic burden and a peaceful passing away. We feel that this could be an alternative, more humane option for such patients.

Ultrasound-Guided Microwave Ablation for the Management of Inguinal Neuralgia: A Preliminary Study with 1-Year Follow-up

PURPOSE

To evaluate the feasibility and efficacy of ultrasound-guided microwave ablation for the treatment of inguinal neuralgia.

MATERIALS AND METHODS

A retrospective review of 12 consecutive ultrasound-guided microwave ablation procedures was performed of 10 consecutive patients (8 men, 2 women; mean age, 41 years [range, 15-64 years]), between August 2012 and August 2016. Inclusion criteria for inguinal neuralgia included clinical diagnosis of chronic inguinal pain (average, 17.3 months [range, 6-46 months]) refractory to conservative treatment and a positive nerve block. Pain response-reduction of pain level and duration and percent pain reduction using a 10-point visual analog scale (VAS) at baseline and up to 12 months after the procedure-was measured. Nine patients had pain after the inguinal hernia repair, and 1 patient had pain from the femoral artery bypass procedure. The microwave ablation procedure targeted the ilioinguinal nerve in 7 cases, the genitofemoral nerve in 4 cases, and the iliohypogastric nerve in 1 case.

RESULTS

Average baseline VAS pain score was 6.1 (standard deviation, 2.5). Improved pain levels immediately after the procedure and at 1, 6, and 12 months were statistically significant (P = .0037, .0037, .0038, .0058, respectively). Also, 91.7% (11/12) of the procedures resulted in immediate pain relief and at 1 month and 6 months. At 12 months, 83.3% (10/12) of patients had an average of 69% ± 31% pain reduction. Percent maximal pain reduction was 93% ± 14% (60%-100%), and the average duration of clinically significant pain reduction was 10.5 months (range, 0-12 months.). No complications or adverse outcomes occurred.

CONCLUSIONS

Ultrasound-guided microwave ablation is an effective technique for the treatment of inguinal neuralgia after herniorrhaphy.

Iatrogenic Phenol Injury Causing Facial Paralysis With Tympanic Membrane and Ossicular Necrosis

OBJECTIVE

To describe a serious iatrogenic injury and propose means of reducing the risk of its reoccurrence.

PATIENTS

A 21-year-old man who suffered facial paralysis, complete necrosis of the tympanic membrane, and ossicular discontinuity because of chemical burn from accidental application of copious amounts of topical anesthetic phenol into the ear.

INTERVENTIONS

Conservative management of facial paralysis and delayed reconstruction of the tympanic membrane and ossicular chain.

MAIN OUTCOME MEASURES

Gradual recovery to grade 1/6 facial function, successful repair of the tympanic membrane, but persistent 30-dB conductive hearing loss after partial ossicular replacement prosthesis presumably because of scarring.

CONCLUSION

Phenol is a highly toxic chemical, topically to both skin and eyes. Absorbed through the skin it can have lethal cardiotoxicity. It is also potent neurotoxin at concentrations much lower (4-7%) than used for tympanic membrane anesthesia (89%) and has long been used therapeutically to destroy nerves in patients of contractions or intractable pain. Otologists need to have a healthy respect for the dangers of using phenol. As only a minute quantity is needed for tympanic anesthesia, commercially available prepackaged applicators are preferred. Storage of stock bottles of 89% phenol solutions in clinical settings risks injury to both patients and practitioners.

Percutaneous dorsal root ganglion lysis with phenol for the treatment of pain associated with thoracic compression fracture

BACKGROUND

Symptomatic thoracic compression fracture is one of the most common causes of back pain in elderly. Although vertebroplasty is widely utilized in patients when conservative treatment fails, we introduced an alternative percutaneous technique for the treatment of thoracic compression pain.

METHODS

This in a retrospective study. The analysis was performed on 28 consecutive patients who underwent undergoing percutaneous dorsal root ganglion lysis with phenol for the treatment of pain associated with thoracic compression fracture. An acceptable treatment outcome was operationally defined as a pain intensity numerical rating scale (NRS) score of 3 or lower or EQ-5D index of 0.672 or higher. The primary outcome was pain relief and acceptable treatment outcome at 1 day, 1 week, 1 month, and 1 year.

RESULTS

Of the 28 cases treated with our procedures, the change in mean NRS score between baseline and one day was -2.5 (95 % CI -1.6 ~ -3.4, p < 0.001), between baseline and one week was -4.7 (-4.1 to -5.3, p < 0.001), between baseline and one month was -5.8 (-5.2 to -6.5, p < 0.001), and between baseline and one year was -6.3 (-5.6 to -7.1, p < 0.001). An acceptable treatment outcome was 14 % one day after the procedure, 46 % at one week, 72 % at one month, and 84 % at one year. Complication rate was 3.6 %.

CONCLUSIONS

For thoracic compression fracture patients, percutaneous dorsal root ganglion lysis with phenol is an effective, and safe alternative treatment method worth considering. Pain relief is fast and persists for one year.

Transforaminal 5% phenol neurolysis for the treatment of intractable cancer pain

This is the first case report of using a transforaminal approach for phenol administration. A 76-yr-old patient with a history of leiomyosarcoma and multiple metastatic lesions had unremitting pain in the right thoracic and lumbar regions and had prohibitive opioid-induced side effects. The patient underwent phenol neurolysis using a transforaminal approach in 2 stages at 3 levels (L3-4, L1-2, and T12-L1). The patient had complete resolution of pain, without any complications, and opioid treatment was nearly discontinued. Transforaminal phenol neurolysis is a reasonable treatment option for patients suffering from intractable pain for whom conventional therapies have proven ineffective.