Rinko Kokubo

Ketamine for acute neuropathic pain in patients with spinal cord injury

Ketamine, an N-methyl-d-aspartic acid (NMDA) receptor antagonist, may be useful for treating neuropathic pain, which is often difficult to control. We report a prospective study of 13 patients with acute neuropathic pain due to spinal cord injury (SCI) treated with ketamine. All underwent a test challenge with 5mg ketamine. Patients with satisfactory responses were then treated intravenously and subsequently perorally with ketamine. Pre- and post-treatment pain was recorded on a visual analogue scale. All 13 patients responded positively to the ketamine test challenge and underwent continued ketamine administration. At the cessation of treatment and alter at final follow up, pain was decreased by 74.7% and 96.8%, respectively. The average administration period was 17.2 days; it was longer (59 days) in one patient treated in the subacute phase. All patients suffered allodynia-type pain and experienced 30% or less of their original pain intensity upon test challenge. Side effects were noted in five patients, although their severity did not require treatment cessation. In patients with SCI, ketamine reduced allodynia. Particularly good results were obtained in patients treated in the acute phase and these patients did not experience post-treatment symptom recurrence. Our results suggest that in patients with SCI, ketamine is useful for treating neuropathic pain in the acute phase.

Prospective assessment of concomitant lumbar and chronic subdural hematoma: is migration from the intracranial space involved in their manifestation?

OBJECT Spinal subdural hematomas (SDHs) are rare and some are concomitant with intracranial SDH. Their pathogenesis and etiology remain to be elucidated although their migration from the intracranial space has been suggested. The authors postulated that if migration plays a major role, patients with intracranial SDH may harbor asymptomatic lumbar SDH. The authors performed a prospective study on the incidence of spinal SDH in patients with intracranial SDH to determine whether migration is a key factor in their concomitance. METHODS The authors evaluated lumbar MR images obtained in 168 patients (125 males, 43 females, mean age 75.6 years) with intracranial chronic SDH to identify cases of concomitant lumbar SDH. In all cases, the lumbar MRI studies were performed within the 1st week after surgical irrigation of the intracranial SDH. RESULTS Of the 168 patients, 2 (1.2%) harbored a concomitant lumbar SDH; both had a history of trauma to both the head and the hip and/or lumbar area. One was an 83-year-old man with prostate cancer and myelodysplastic syndrome who suffered trauma to his head and lumbar area in a fall from his bed. The other was a 70-year-old man who had hit his head and lumbar area in a fall. Neither patient manifested neurological deficits and their hematomas disappeared under observation. None of the patients with concomitant lumbar SDH had sustained head trauma only, indicating that trauma to the hip or lumbar region is significantly related to the concomitance of SDH (p < 0.05). CONCLUSIONS As the incidence of concomitant lumbar and intracranial chronic SDH is rare and both patients in this study had sustained a direct impact to the head and hips, the authors suggest that the major mechanism underlying their concomitant SDH was double trauma. Another possible explanation is hemorrhagic diathesis and low CSF syndrome.

Low Back Pain Caused by Superior Cluneal Nerve Entrapment Neuropathy in Patients with Parkinson Disease

n patients with Parkinson disease (PD), postural abnormalities and increased muscle tonus lead to musculoskeletal I problems. The incidence of such problems was significantly higher in patients with PD than in an age-matched control group comprising patients with stroke and brain tumor. Low back pain (LBP) in particular was reported more frequently by patients with PD; in approximately 50%, it negatively affected their quality of life and activities of daily living (ADL). It is difficult to treat LBP in patients with PD, and the results of surgery to address their spinal diseases are unsatisfactory.

Common diseases mimicking lumbar disc herniation and their treatment

1Department of Neurosurgery, Chiba Hokuso Hospital, Nippon Medical School, Inzai-city, Chiba 270-1694, Japan. 2Department of Neurosurgery, Kushiro Rosai Hospital, Kushiro-city, Hokkaido 085-0088, Japan. 3Department of Neurosurgery, Nippon Medical School, Bunkyo-ku, Tokyo 113-8603, Japan. 4Department of Neurosurgery, Teikyo University, Itabashi-ku, Tokyo 173-8606, Japan. 5Department of Neurosurgery, Iwate Medical University, Morioka-city, Iwate 020-8505, Japan.

Superior Cluneal Nerve Entrapment Neuropathy and Gluteus Medius Muscle Pain: Their Effect on Very Old Patients with Low Back Pain

OBJECTIVE In the very elderly, their general condition and poor compliance with drug regimens can render the treatment of low back pain (LBP) difficult. We report the effectiveness of a less-invasive treatment for intractable LBP from superior cluneal nerve entrapment neuropathy (SCN-EN) and gluteus medius muscle (GMeM) pain. PATIENTS AND METHODS Between April 2013 and March 2015, we treated 17 consecutive elders with LBP, buttock pain, and leg pain. They were 4 men and 13 women ranging in age from 85 to 91 years (mean 86.6 years). We carefully ascertained that their symptoms were attributable to SCN-EN and GMeM pain. The median follow-up period was 21.5 ± 12.2 months (range 2-35 months). RESULTS SCN-EN was diagnosed in 15 patients (28 sites) and GMeM pain in 14 (27 sites). In 5 patients, we obtained symptom control by local block (Numerical Rating Scale for LBP: declined from 7.8 to 0.8 [P < 0.05], Roland-Morris Disability Questionnaire score: declined from 16.5 to 5.2). The other 12 were operated under local anesthesia (SCN neurolysis, GMeM decompression). As 3 patients reported the persistence of leg pain postoperatively, they subsequently underwent peroneal nerve neurolysis and surgery for tarsal tunnel syndrome. These treatments resulted in significantly symptom abatement (Numerical Rating Scale: from 8.2 to 1.7, Roland-Morris Disability Questionnaire score: from 12.8 to 8.6; P < 0.05). CONCLUSIONS Even very old patients with intractable LBP, buttock pain, and leg pain due to SCN-EN or GMeM pain can be treated successfully by peripheral block and less-invasive surgery under local anesthesia.

The Impact of Tarsal Tunnel Syndrome on Cold Sensation in the Pedal Extremities.

OBJECTIVE Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve in the tarsal tunnel. It is not known whether vascular or neuropathic factors are implicated in the cause of a cold sensation experienced by patients. Therefore, we studied the cold sensation in the pedal extremities of patients who did or did not undergo TTS surgery. METHODS Our study population comprised 20 patients with TTS (38 feet); 1 foot was affected in 2 patients and both feet in 18 patients. We acquired the toe-brachial pressure index to evaluate perfusion of the sole and toe perfusion under 4 conditions: the at-rest position (condition 1); the at-rest position with compression of the foot dorsal artery (condition 2); the Kinoshita foot position (condition 3); and the Kinoshita foot position with foot dorsal artery compression (condition 4). Patients who reported abatement in the cold sensation during surgery underwent intraoperative reocclusion of the tibial artery to check for the return of the cold sensation. RESULTS The toe-brachial pressure index for conditions 1 and 3 averaged 0.82 ± 0.09 and 0.81 ± 0.11, respectively; for conditions 2 and 4, it averaged 0.70 ± 0.11 and 0.71 ± 0.09, respectively. Among the 16 operated patients, the cold sensation in 7 feet improved intraoperatively; transient reocclusion of the tibial artery did not result in the reappearance of the cold sensation. CONCLUSIONS Our findings suggest that the cold sensation in the feet of our patients with TTS was associated with neuropathic rather than vascular factors.

Deep Decompression of the Lateral Femoral Cutaneous Nerve Under Local Anesthesia

OBJECTIVE Meralgia paresthetica is a mononeuropathy of the lateral femoral cutaneous nerve (LFCN) caused by compression around the inguinal ligament. We report a surgical alternative for the treatment of meralgia paresthetica under local anesthesia and its outcomes. METHODS We operated on 12 patients with unilateral meralgia paresthetica whose age at surgery ranged from 62 to 75 years. The mean postoperative follow-up period was 19 months. Microsurgical deep decompression of LFCN was performed with the patient under local anesthesia. Clinical outcomes of surgical treatment were assessed based on the patients most recent follow-up visit and were classified into 3 categories: complete, partial, or no relief of symptoms. Symptoms of pain or numbness in the anterolateral part of the thigh were evaluated, using a visual analog scale, before surgery and after surgery, i.e., at the most recent follow-up visit. RESULTS All patients reported symptom improvement: complete relief in 9 patients (75%) and partial relief in 3 patients (25%). In the 3 patients with partial relief, the remaining symptoms did not affect their daily living. Overall, the visual analog scale scores were significantly improved in all patients (P < 0.05), and no patient experienced postoperative recurrence of their symptoms at the time of the last follow-up visit. CONCLUSIONS Symptoms of meralgia paresthetica can resemble those of a lumbosacral disorder. Microsurgical deep decompression under local anesthesia produces good surgical outcomes. The use of local anesthesia contributes not only to reduction of pain during surgery but also eliminates excessive surgical procedures and reduces the duration of hospital stay.