Neuropathic pain medications are often administered for prolonged periods, thus their long-term safety is important. We conducted a post-marketing surveillance for mirogabalin in patients with peripheral neuropathic pain, to investigate incidences of diabetes mellitus (DM: aggravation, development), vision disorders, hypoglycemia, sudden deaths, and other adverse events (AEs) during 12 months of starting mirogabalin treatment. The safety analysis set included 1,519 patients; 259 with DM and 1,260 without DM. Of the 660 patients who continued treatment, 424 (64.2％) did not reach the effective dose according to the package insert, with six of these cases (1.4％) due to AEs. Of the 859 patients who discontinued treatment, 66 (7.7％) discontinued due to AEs. Incidences of DM (aggravation, development), and vision disorders were 4.25％ (11/259), 0.08％ (1/1,260), and 0.07％ (1/1,519), respectively. No hypoglycemia or sudden deaths occurred. In this surveillance on long-term mirogabalin treatment, no new safety concerns regarding DM (aggravation, development), vision disorders, hypoglycemia, sudden deaths, or other AEs were observed.

We investigated utility of the pain disability assessment scale (PDAS) for evaluating the treatment outcome in people with a musculoskeletal pain other than low back pain (M group) and with a non-musculoskeletal pain (NM group). One hundred and one patients, who visited the Interdisciplinary Pain Center of Keio University Hospital from July 2018 to February 2020, were included. Pain intensity and disability were assessed using the numerical rating scale (NRS) and PDAS at the first visit and at 3 months. Both groups showed a significant decrease in NRS during the 3-month-treatment period (M group: p＜0.001, NM group: p＝0.02), while the PDAS significantly improved only in the M group (p＝0.01). Improvement of the PDAS was significantly correlated with decrease of NRS in the M group (p＜0.001). However, there was no correlation between the PDAS and NRS in the NM group (p＝0.91), suggesting the need for a highly disease-specific assessment for disability.

The patient is a 41-year-old woman diagnosed with CREST syndrome three years ago. A lumpectomy was scheduled under an axillary brachial plexus block for a finger calcification lesion associated with this disease. The ultrasound-guided nerve block was performed with 25 ml of 0.25％ levobupivacaine, mainly on the median and radial nerves. No abnormal sensations were noted at the time of puncture. She complained of prolonged numbness and pain from the left forearm to the entire fingers after surgery. She exhibited allodynia on the ulnar side, with no signs of motor paralysis or sensory loss. She had Raynaud's phenomenon, and a history of marked ischemic changes at the finger ends after finger block. The cause of the peripheral neuropathy in the present case was thought to be nerve damage from the needle, nerve ischemia from local anesthetic, and hyperextension or compression due to intraoperative and postoperative positioning.

We report a case of intrathecal analgesia with high-dose morphine and bupivacaine for refractory cancer pain management. A patient in her 40s who had undergone radical hysterectomy and chemoradiotherapy for cervical cancer complained of pain and numbness from the right lateral flank to the front of the right thigh. She had familial amyloidotic polyneuropathy (FAP). The CT scan showed a recurrent mass with lumbar plexus invasion, which might cause the pain. Oral oxycodone 80 mg/day and hydromorphone 24 mg/day caused drowsiness but did not alleviate the pain. An intrathecal port was implanted. Intrathecal morphine 1.2 mg/day and bupivacaine 12 mg/day were administered, and finally morphine 60.48 mg/day and bupivacaine 77.76 mg/day were required. Despite high-dose bupivacaine, she could walk. The numerical rating score was improved from 8 to 1–2/10. The reasons for requiring high dose may be related to disease progression, mass formation associated with high-dose morphine and FAP.

Although microscopic varicocelectomy is a highly effective treatment for painful varicocele, scrotal pain remains after the surgery in many cases. Here we report a case of chronic scrotal pain in which ultrasound-guided spermatic cord block was successful. The patient was a man in his 40s. Microscopic varicocele removal was performed for a varicocele with scrotal pain, but the pain persisted even after the surgery. Not only was the patient suffering from dull continuous pain, but also breakthrough pain induced by sitting, which was interfering with his daily life. The patient was unresponsive to analgesics and herbal medicines. After ultrasound-guided spermatic cord block, the persistent pain was relieved and the frequency of breakthrough pain decreased after treatment. Spermatic cord block is a nerve block that is effective for analgesia after vasectomy or varicocelectomy, and may be a treatment option for chronic scrotal pain that does not respond to pharmacological therapy.