Ultrasound-guided preperitoneal phenol neurolysis for palliative pain.

Dear Editor,

We want to congratulate Dr. ElSharkawy et al.[1] for their prospective controlled randomized study, and we want to add a further contribution to the discussion. The preperitoneal block is characterized by effectiveness, simplicity, and safety. With a low rate of technical failure (~1%) and zero toxicity.

In a recent meta-analysis, the evidence supports the use of this technique as it is as effective as epidural analgesia and could be favored based upon recovery parameters and patient satisfaction.[2]

We want to describe our experience performing preperitoneal phenol lysis for palliative pain.

A 78-year-old man diagnosed with pancreatic cancer and hepatic metastasis, ECOG 3, was referred to our pain unit. He had undergone biopsy surgery but refuse chemotherapy regimens. His treatment included only tramadol 200 mg/d and alprazolam de 0.5 mg, due to hepatic dysfunction.

His treatment included a celiac plexus block that was effective for two weeks, and he commented that the procedure was painful. Despite multimodal analgesia, he reported a Numerical Rating Scale (NRS) of 9/10. He also reported nausea, dyspnea and constipation. Cancer progressed, and the patient was no candidate for surgery. A CT scan confirmed omental metastases.

After discussion with the patient and her relatives, and due to refuse of the patient to receive another celiac plexus block; an ultrasound-guided erector spinae plane block was scheduled. The patient gave written consent to publish her case report and images.

The procedure was performed under noninvasive monitoring using a curvilinear low-frequency ultrasound probe (Sonosite, USA), looking for the T11 vertebral lamina. A total of 10 mL 0,5% ropivacaine +4 mg dexamethasone were administered on each side. Twenty minutes later, her pain decreased to 0/10 NRS at the epigastric and hypochondriac regions, but remained at the umbilical region. Therefore, we applied a preperitoneal block in the same way with a linear probe; then he reported completed analgesia.

Two weeks later, the pain returned in the same way. Given the patient’s advanced malignancy and fragile condition, and based on previous publications supporting this approach,[34] a neurolytic block was discussed to avoid more patient interventions and exposure, particularly during COVID times. This time, a total volume of 10 mL of 10% aqueous phenol solution was injected in fractional doses of 1 mL per minute on each side. We obtained the same result, so we proposed ultrasound-guided preperitoneal lysis.

The procedure was performed under noninvasive monitoring in the supine position. We applied 20 mL of ropivacaine 0.2% combined with 20 mL of 10% phenol. After negative aspiration, the mixture was injected in 2-mL increments per minute while observing an adequate fluid spread [Figure 1]. Twenty minutes later, he reported an NRS of 0/10. One week later, he noted the same relief until he died almost 2 months later. No more opioids were required after the procedure.

Figure 1

Sonoanatomy of preperitoneal neurolytic block

The presented case illustrates the efficacy of a minimally invasive technique in a complex patient with cancer-related pain. Further studies are needed to confirm long-lasting analgesia and to clarify the optimal concentration and dose.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.