A 72-year-old woman (40.3 kg, 139 cm) was referred to our pain clinic for the treatment of low back pain after two back surgeries. She had first undergone back surgery [posterior lumbar interbody fusion (PLIF at L4–5) plus spinal stabilization (L3)] for lumbar spinal canal stenosis 4 years prior to the current presentation. Two weeks after the initial surgery, she underwent reoperation because of screw placement errors, and her symptoms disappeared after surgery. However, her low back pain recurred after a fall 5 months before the current presentation. Paralysis of the lower limbs was not apparent after this episode. A sensory disturbance that had existed before the surgeries remained unchanged. No new lesions such as a lateral recess or foraminal stenosis, herniated nucleus pulposus, or fracture were found on radiographs or magnetic resonance images (Fig. ). The previous medical institution prescribed acetaminophen and tramadol for low back pain and performed a caudal epidural block with 5 ml of 1% lidocaine and dexamethasone 1.65 mg. However, neither treatment provided pain relief, and the patient was referred to our pain clinic. She had several comorbidities, including diabetes mellitus, hypertension, renal dysfunction, hypothyroidism, rheumatic arthritis, and gastroesophageal regurgitation, and was prescribed 27 different drugs by clinicians from five different facilities. Accordingly, we decided not to use additional medication for first-line therapy because of polypharmacy concerns and renal dysfunction and performed bilateral ESP block with the patient in the prone position. A convex type transducer was placed in a longitudinal orientation at the level of the L2 transverse process, 3 cm lateral to the midline. The L4 and L5 transverse processes could not be identified because of the echogenic artifacts due to the surgical instruments. The posterior surface of the L2 transverse process was identified using an aseptic technique. After the puncture point was anesthetized with 2 ml of 1% lidocaine, the needle was inserted in the plane of the ultrasound beam in a cephalad to caudal direction. Following confirmation of the needle tip on the surface of the transverse process of L2, 20 ml of 0.1875% ropivacaine (fourfold dilution of commercial product) was injected into the target plane between the erector spinae muscles and the transverse process (Fig. ). This procedure was repeated on the contralateral side. Twenty-five minutes later, the patient reported a warm feeling in her low back and almost complete relief from pain, which was approximately < 10% of its original severity. There was an area of diminished cold sensation extending from T12 to L5, with no change in the anterior and lateral abdomen. Unfortunately, the pinprick test was not performed. Pain relief lasted for approximately 10 h after the initial block. We repeated this procedure for a total of three times in a month. Finally, the patient reported that her daily baseline level of low back pain had diminished to < 40% of its original severity. She was satisfied with the extent of pain control and did not wish to undergo further treatments such as epiduroscopy or spinal cord stimulation (SCS).
Our patient, a 52-year-old male (165 cm, 90 kg), was a known case of chronic lymphocytic leukemia (CLL, Rai Stage II). He had received two cycles of bendamustine and rituximab-based chemotherapy in two consecutive months. He developed herpes zoster infection in the following month and was started on oral acyclovir after consultation with a dermatologist. One week later, he visited our pain clinic and complained of severe pain on the right side of his lower back []. The pain was burning in nature and was associated with allodynia and restricted mobility. A diagnosis of PNH was made, and he was started on gabapentin in view of neuropathic nature of pain. The dermatomal distribution of the pain was from T11 to S1. The pain was affecting the quality of life of the patient and the pharmacological therapy was inadequate.\nWe decided to perform a right-sided ESPB in prone position for acute pain relief of the patient. A high-frequency linear ultrasound probe was placed in longitudinal orientation, about 3 cm lateral to the spinous process of the third lumbar vertebra. The interfacial plane below the erector spinae muscle was identified, and 0.25% bupivacaine and triamcinolone 40 mg (total volume 30 ml) were injected []. Patient's NRS score was decreased from 8/10 to 3/10 30 min after the block procedure. Later on, the ESPB was performed two times for 2 weeks and provided effective analgesia for the PHN. The patient reported a decline in pain score and analgesics consumption in follow-up clinics.