A. Ram Doo

Background: This study investigated the relationship between intraoperative requirement for an inhalational anesthetic (sevoflurane) or an opioid (remifentanil) and postoperative analgesic consumption. Methods: The study included 200 adult patients undergoing elective laparoscopic colectomy. In the sevoflurane group, the effect-site concentration of remifentanil was fixed at 1.0 ng/ml, while the inspiratory sevoflurane concentration was adjusted to maintain an appropriate anesthetic depth. In the remifentanil group, the end-expiratory sevoflurane concentration was fixed at 1.0 volume%, and the remifentanil concentration was adjusted. Pain scores and cumulative postoperative analgesic consumptions were evaluated at 2, 6, 24, and 48 h after surgery. Results: Average end-tidal concentration of sevoflurane and effect-site concentration of remifentanil were 2.0 ± 0.4 volume% and 3.9 ± 1.4 ng/ml in the sevoflurane and remifentanil groups, respectively. Cumulative postoperative analgesic consumption at 48 h postoperatively was 55 ± 26 ml in the sevoflurane group and 57 ± 33 ml in the remifentanil group. In the remifentanil group, the postoperative cumulative analgesic consumptions at 2 and 6 h were positively correlated with intraoperative remifentanil requirements (2 h: r = 0.36, P < 0.01; 6 h: r = 0.38, P < 0.01). However, there was no significant correlation in the sevoflurane group (r = 0.04, P = 0.69). Conclusions: The amount of intraoperative requirement of short acting opioid, remifentanil, is correlated with postoperative analgesic consumption within postoperative 6 h. It may be contributed by the development of acute opioid tolerance. However, intraoperative sevoflurane requirement had no effect on postoperative analgesic consumption.

Rehabilitation of lower limb amputation in developing countries is quite challenging. Though there are basic to highly advanced prostheses available in India, the set-up is still facing difficulties in developing countries. Prosthetic management is difficult due to lack of availability of prostheses and reduced affordability among low income populations. In this review we highlighted the lower limb amputation and prosthetic rehabilitation status in India. Currently, India is advancing well in the rehabilitation field, but further studies are required to provide more evidence and recommendation.

Ye Sull Kim, SeongOk Park, Chanhong Lee, Sang-Kyi Lee, A Ram Doo, and Ji-Seon Son. Korean J Pain 2023;36:98-105. https://doi.org/10.3344/kjp.22227

Cancer patients are increasing in number, with an increased lifespan and advances in cancer treatment. Palliative care physicians often encounter difficulties in caring for patients with pain. In addition to cancer-related pain, patients with cancer may suffer from various musculoskeletal diseases, resulting in significant functional limitations of physical activities of daily living. We present three cases illustrating methods to deal with nonspecific mechanical low-back pain in patients with advanced cancer. We provide our therapeutic experiences, focusing on the usefulness of radiofrequency treatment in palliative care in patients with cancer.

This prospective observational study evaluated the effects of body fat on the pharmacologic effect of propofol. Hundred patients aged 18 to 75 years who were scheduled to undergo orthopedic surgery under regional block were enrolled. All participants underwent bioelectrical impedance analysis and were allocated into 2 groups: the high and normal adiposity group, according to percent body fat. Following successful regional block, propofol was incrementally infused until loss of consciousness (LOC) with a target-controlled infusion pump. The effect-site concentration of propofol at LOC and the total infused dose of propofol per total body weight until LOC were recorded. At the end of the surgery, the infusion of propofol was stopped. The elapsed time to recovery of consciousness (ROC) and the effect-site concentration at ROC were recorded. These pharmacologic data were compared between 2 groups. The effect-site concentration of propofol at LOC (µg/mL) was significantly lower in the high adiposity group than in the normal group in both sexes (3.5 ± 0.4 vs 3.9 ± 0.6; P = .020 in males, and 3.4 [interquartile range: 2.9–3.5] vs 3.8 [interquartile range: 3.3–3.9]; P = .006 in females). Total dose per total body weight until LOC (mg/kg) were also significantly lower in the high adiposity group than in the normal group. There was no significant difference in the data related to ROC. The pharmacologic effects of propofol may be affected by the composition of body components. The concentration of propofol using a target-controlled infusion system may be diminished in patients with a high proportion of body fat.

Rationale: Herniation of the thoracic intervertebral disc (HTD) is a rare disease that accounts for <1% of all disc herniations. Physicians may make diagnostic errors due to the variable clinical features and limited experience of HTD. In this report, we present 2 unusual cases of HTD. Patient concerns: A 72-year-old woman (case 1) visited our pain clinic because of chronic abdominal discomfort with visible bulging on the left side. Atrophy of the abdominal wall muscle and quadratus lumborum was observed. The therapeutic effect of interfascial plane block to exclude the possibility of truncal neuropathy following muscular atrophy was temporary. The other patient, a 75-year-old man (case 2) complained of aggravation of previously diagnosed postherpetic neuralgia. An extension of the previously symptomatic area of the forward upper dermatome was observed. Radiofrequency treatment on the symptomatic dorsal root ganglion failed to relieve symptoms. Diagnoses: Two patients underwent magnetic resonance imaging of the spine for further evaluation. The patients were diagnosed with multilevel HTD and foraminal herniated disc, compatible with their symptoms and without myelopathy. Interventions: Two patients were conservatively treated with a fluoroscopy-guided transforaminal epidural block. Outcomes: The 2 patients experienced significant pain reduction up to 50% on a numeric rating scale after repeated treatment. Lessons: Multilevel HTD of the mid- to lower-thoracic spine may present as abdominal bulging with atrophy of the abdominal wall muscles. We also report another case of concomitant symptomatic thoracic radiculopathy from HTD and postherpetic neuralgia at the adjacent level. Thoracic transforaminal epidural block may be considered a conservative therapeutic approach for HTD.

Rationale: Ramsay Hunt syndrome is a type of herpes zoster infection involving geniculate ganglion and facial nerve. Unilateral facial palsy, otalgia, and painful vesicular rash on the auricle and external auditory canal are the typical symptoms. Although postherpetic neuralgia (PHN) is a devastating complication of herpes zoster infection, PHN following Ramsay Hunt syndrome has rarely been reported. Patient concerns: A 55-year-old immunocompetent female patient visited our pain clinic, for left-sided refractory otalgia (PHN) that persisted for 3 months after she was diagnosed with Ramsay Hunt syndrome. Although facial palsy and tinnitus had recovered within 2 to 4 weeks after symptom onset, the patient had been experiencing a persistent and severe otalgia radiating to mandibular angle, temporal and upper cervical area of neuropathic nature. Diagnoses: The patient's pain persisted despite conservative medication and administration of ultrasound-guided stellate ganglion block, facial nerve block, and great auricular nerve block several times. Interventions: The patient was treated with the application of ultrasound-guided pulsed radiofrequency (PRF) to the great auricular nerve. Outcomes: The patient experienced significant pain reduction more than 50% on a numeric rating scale after 2 weeks of PRF treatment. Lessons: Chronic otalgia might be a type of PHN after Ramsay Hunt syndrome with cervical nerve involvement. PRF treatment to the great auricular nerve can be a therapeutic option for refractory otalgia following Ramsay Hunt syndrome.

Seon Woo Yoo, Min-Jong Ki, A Ram Doo, Cheol Jong Woo, Ye Sull Kim, and Ji-Seon Son. Korean J Pain 2021;34:339-45. https://doi.org/10.3344/kjp.2021.34.3.339

Rationale: Several hereditary myopathies that can predispose to malignant hyperthermia (MH) are reported. However, the risk of MH in myotonic dystrophy type I (DM1) has been suggested equal to general population, although the evidence is limited to only a few case reports. Patient concerns: We encountered a rare case of MH during anesthesia induction with sevoflurane in a male adolescent with previously undiagnosed DM1. Diagnoses: After the event, genetic testing revealed the presence of a previously unknown heterozygous missense mutation in ryanodine receptor 1 (RYR1) associated with MH (c.6898T > C; p.ser2300Pro). Concomitantly, the patient was diagnosed with DM1 with abnormal cytosine-thymine-guanine triplet expansion in the DMPK gene. Interventions: Dantrolene was administered to treat the hypermetabolic manifestations in 20 minutes after the identification of MH. Outcomes: The patient was successfully treated and discharged without any complications. Laboratory abnormalities were recovered to baseline at postoperative 4 days. Lessons: The authors suggest that possible MH susceptibility in DM1 patients may be refocused. Genetic testing can be a screening tool for MH susceptibility in these population, prior to receiving general anesthesia.