Background & Aims
Many patients with spinal dorsal root avulsion experience intractable pain characterized by unbearable electrical shooting pain. Pain following spinal root avulsion is often unresponsive to medication and block therapy. After root avulsion, the lack of normal sensory input to the dorsal horn and direct injury of the dorsal horn result in hyperactivity of pain-related neurons. Dorsal root entry zone (DREZ) lesioning, developed in the 1970s, has been applied to alleviate spinal root avulsion pain. Representative surgical methods include RF-lesioning using Nashold’s needle electrode and microsurgical DREZotomy using a bipolar coagulator [4,6,7]. This study reports on the long-term outcomes of DREZ-lesioning performed at Osaka University Hospital for spinal root avulsion pain.
Methods
We retrospectively collected information on patients with spinal root avulsion pain who underwent DREZ-lesioning at Osaka University Hospital since 2002. This included pain intensity and extent of both electrical shooting and continuous pain, and frequency and duration of electrical shooting pain before surgery, soon after surgery, and at the last follow-up. “Effective” was defined as more than 50% improvement in these endpoints. Information on surgical complications was also gathered.
Distribution of sensorimotor disturbance and pain location were confirmed to identify the neurological level of injury. Spinal MRI, myelography, and CT scan after myelography were performed to identify the radiological level of injury. Nashold’s method, RF thermal coagulation, using a 2mm needle electrode was adopted. After hemilaminectomy, DREZ with avulsion was coagulated at 1mm intervals under intraoperative neuromonitoring.
Results
Thirty patients with spinal root avulsion pain underwent DREZ-lesioning with a median follow-up of 50 months (IQR, 13-75 months). Electrical shooting pain completely resolved in 23 patients soon after surgery and in 18 patients at the last follow-up. Continuous pain completely resolved in 10 patients soon after surgery and in five patients at the last follow-up. 25 patients remained effective (?50% pain relief) for electrical shooting pain, and eight for continuous pain at the last follow-up. Mean pain scores (range, 0-10) decreased from 8.9 for electrical shooting pain and 5.2 for continuous pain to 2.6 and 3.7, respectively. Permanent slight motor and sensory impairment were observed in one and two patients, respectively.
Conclusions
Although there are no randomized controlled trials of DREZ-lesioning, more than a dozen case series with over 300 reported cases indicated that it resulted in good outcomes (?50% pain relief) in 50-100% of patients [3,5]. It was particularly effective for paroxysmal electrical shooting pain [1,2,5-8]. When deciding on the indication for DREZ-lesioning, it is crucial to evaluate each type of pain, i.e., paroxysmal electrical shooting pain and continuous pain. DREZ-lesioning is effective for electrical shooting pain after spinal root avulsion and is a promising treatment for the future.
References
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[2] Ali M, Saitoh Y, Oshino S, Hosomi K, Kishima H, Morris S, Shibata M, Yoshimine T. Differential efficacy of electric motor cortex stimulation and lesioning of the dorsal root entry zone for continuous vs paroxysmal pain after brachial plexus avulsion. Neurosurgery 2011;68(5):1252-1257; discussion 1257-1258.
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[4] Nashold BS, Jr., Ostdahl RH. Dorsal root entry zone lesions for pain relief. J Neurosurg 1979;51(1):59-69.
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[6] Sindou M, Mertens P, Wael M. Microsurgical DREZotomy for pain due to spinal cord and/or cauda equina injuries: long-term results in a series of 44 patients. Pain 2001;92(1-2):159-171.
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Presenting Author
Koichi Hosomi
Poster Authors
Koichi Hosomi
MD, PhD
Osaka University
Lead Author
Satoru Oshino MD
PhD
Department of Neurosurgery, Osaka University Graduate School of Medicine
Lead Author
Akihiro Yamamoto MD
Department of Neurosurgery, Osaka University Graduate School of Medicine
Lead Author
Nobuhiko Mori
Osaka University Graduate School of Medicine
Lead Author
Takufumi Yanagisawa MD
PhD
Osaka University Institute for Advanced Co-Creation Studies
Lead Author
Naoki Tani MD
PhD
Department of Neurosurgery, Osaka University Graduate School of Medicine
Lead Author
Manabu Sasaki MD
PhD
Department of Neurosurgery, Hanwa Memorial Hospital, Osaka University Graduate School of Medicine
Lead Author
Youichi Saitoh MD
PhD
Tokuyukai Rehabilitation Clinic, Osaka University Graduate School of Engineering Science
Lead Author
Haruhiko Kishima MD
PhD
Department of Neurosurgery, Osaka University Graduate School of Medicine
Lead Author
Topics
- Specific Pain Conditions/Pain in Specific Populations: Neuropathic Pain - Central