Neuromodulation of the Dorsal Root Ganglion for Chronic Postsurgical Pain.

OBJECTIVE: The objective of this study is to review the available evidence for dorsal root ganglion (DRG) stimulation for the treatment of complex regional pain syndrome type II (CRPS II; peripheral causalgia) associated with chronic neuropathic postsurgical pain (NPP). DESIGN: Available literature was identified through a search of the US National Library of Medicine's Medline database, PubMed.gov. References from published articles also were reviewed for relevant citations. RESULTS: The data published to date support the use of DRG stimulation to treat chronic NPP of the groin, knee, and foot. NPP following procedures such as thoracotomy, hernia surgery, and knee replacement surgery were identified as some of the conditions for which DRG stimulation is likely to be effective. CONCLUSION: DRG stimulation is known to be an effective treatment for focal neuropathic pain. Currently, NPP of the foot, groin, and knee all appear to be the conditions with the most clinical experience, backed by a limited but growing body of evidence. However, prospective studies lag behind real-world clinical experience and are needed to confirm these findings.

Dorsal Root Ganglion Stimulation Is Paresthesia-Independent: A Retrospective Study.

INTRODUCTION: Neuromodulation is an important tool for achieving pain relief in otherwise-intractable neuropathic pain conditions. Dorsal root ganglion (DRG) stimulation, in which primary sensory neurons are stimulated prior to their entry into the spinal canal, provides treatment with high levels of dermatomal specificity and can provide advantages compared to conventional spinal cord stimulation. Although DRG stimulation can produce perceptible paresthesias, many patients operate their systems at subthreshold amplitudes that do not elicit this sensation. Pain relief both with and without paresthesia was investigated in this retrospective analysis. MATERIALS AND METHODS: A retrospective review of all qualifying permanent DRG stimulation systems at a single center over more than a three-year period was completed. Pain (0-10 numeric rating scale) was assessed at baseline, at the end of the trial, and after three, six, and twelve months of treatment. Patients were categorized based on their usage of the stimulator at amplitudes that either did or did not produce paresthesias. RESULTS: Of the 39 patients, 34 (87%) reported having no-paresthesias at any of the follow-up visits. Average pain relief was 73.9% after the trial period and 63.1% after 12 months of treatment. The responder rate (50% or better pain relief) after three months of treatment was more than 80%. Exploratory subgroup analyses showed that similar degrees of pain relief were achieved in numerous body regions and with various pain etiologies. The five patients who reported paresthesias during treatment had pain relief similar to those of the group that did not experience paresthesias. DISCUSSION: Clinically significant and sustained pain relief over more than a period of 12 months was achieved with DRG stimulation programmed at amplitudes below the perceptual level. Thus, the reported analgesia was paresthesia-independent. That good clinical outcomes were observed independent of the generation of paresthesia in DRG stimulation suggests several mechanisms of action, including the inhibition of supraspinal regions involved in somatic paresthesia sensation. The retrospective results presented here posit that future prospective study of DRG stimulation delivered at below the threshold of perceptible paresthesias is warranted.

Comparison of Paresthesia Coverage of Patient's Pain: Dorsal Root Ganglion vs. Spinal Cord Stimulation. An ACCURATE Study Sub-Analysis.

OBJECTIVES: This was a sub-analysis of the ACCURATE clinical trial that evaluated the accuracy and necessity of targeting paresthesia coverage of painful areas with dorsal root ganglion (DRG) stimulation vs. tonic spinal cord stimulation (SCS). MATERIALS AND METHODS: On diagrams of the torso and lower limbs, subjects marked where they felt pain at baseline and paresthesias at three months postimplant. Seventy-five subjects (41 DRG and 34 SCS) with diagrams of sufficient quality were scanned, digitized, and included in this analysis. Subject completed diagrams were digitized and superimposed with a grid of 1398 squares. Quantification of the percentage of bodily areas affected by pain and stimulation induced paresthesias was performed. RESULTS: The percent of painful areas covered by paresthesia was significantly lower for DRG subjects than for SCS subjects (13% vs. 28% of the painful regions, p < 0.05), possibly because significantly more DRG subjects felt no paresthesia during stimulation when compared to SCS subjects (13/41 DRG vs. 3/34 SCS) (p < 0.05). The amount of paresthesia produced outside the painful areas (unrequired paresthesia) was significantly lower in DRG subjects than that of SCS subjects. On average, the percent of unrequired paresthesia was only 20% of the subjects' total painful body surface area in the DRG group compared to 210% in the SCS group (p < 0.01). CONCLUSIONS: The results of this ACCURATE study sub-analysis show that DRG stimulation produces paresthesias, on average, that are less frequent, less intense, with a smaller footprint on the body and less dependent on positional changes.

Motor Cortex Stimulation for Deafferentation Pain.

PURPOSE OF REVIEW: Since the early 1990s, motor cortex stimulation (MCS) has been a unique treatment modality for patients with drug-resistant deafferentation pain. While underpowered studies and case reports have limited definitive, data-driven analysis of MCS in the past, recent research has brought new clarity to the MCS literature and has helped identify appropriate indications for MCS and its long-term efficacy. RECENT FINDINGS: In this review, new research in MCS, repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) are analyzed and compared with historical landmark papers. Currently, MCS is effective in providing relief to 40-64% of patients, with decreasing analgesic effect over time addressed by altering stimulation settings. rTMS and tDCS, two historic, non-invasive stimulation techniques, are providing new alternatives for the treatment of deafferentation pain, with rTMS finding utility in identifying MCS responders. Future advances in electrode arrays, neuro-navigation, and high-definition tDCS hold promise in providing pain relief to growing numbers of patients. Deafferentation pain is severe, disabling, and remains a challenge for patients and providers alike. Over the last several years, the MCS literature has been revitalized with studies and meta-analyses demonstrating MCS effectiveness and providing guidance in identifying responders. At the same time, rTMS and tDCS, two time-honored non-invasive stimulation techniques, are finding new utility in managing deafferentation pain and identifying good MCS candidates. As the number of potential therapies grow, the clinician's role is shifting to personalizing treatment to the unique pain of each patient. With new treatment modalities, this form of personalized medicine is more possible than ever before.

Steroid atrophy scarring treated with fat grafting in a patient with complex regional pain syndrome: A case report.

Subcutaneous atrophy is a known complication of steroid injections. Excellent results with fat grafting for the treatment of steroid atrophy have been documented. However, the benefit of treating steroid-induced subcutaneous atrophy in an extremity diagnosed with complex regional pain syndrome (CRPS) has not been described. CRPS, known formerly as reflex sympathetic dystrophy or RSD, causalgia, or reflex neurovascular dystrophy, is a severe, progressive musculoskeletal pain syndrome characterized by pain which is disproportionate to the severity of the inciting event, edema, or skin changes. Common treatment modalities include pharmacotherapy, physical therapy, and nerve blocks-each therapy producing varying results. We present a literature review of CRPS and the case of a 15-year-old female who developed CRPS of the left lower leg after arthroscopic debridement with retrograde drilling of an osteochondral lesion. Steroid atrophy of the involved area following a saphenous nerve block complicated the patient's treatment course. The area of atrophy was treated with autologous fat grafting. Following the adipose injection procedure, the patient experienced almost complete resolution of her CPRS-associated pain symptoms, along with improved cosmetic appearance of the area.

[Complex regional pain syndrome in a patient with acute drug poisoning: a case report].

We report a case with transition to complex regional pain syndrome (CRPS) caused by nerve injury associated with crush syndrome. The diagnosis was delayed because of coma due to acute drug poisoning. A 44-year-old man had attempted suicide by taking massive amounts of psychotropic drugs 2 days earlier and was transported to our hospital by ambulance. His arms had been compressed due to the prolonged (2 days) consciousness disturbance, and he experienced non-traumatic crush syndrome and rhabdomyolysis. Acute renal failure was prevented with massive infusion and hemofiltration. However, he experienced muscle and nerve injury at the compressed area, which presumably led to CRPS. In cases of suspected crush syndrome associated with acute drug poisoning, it is also important to recognize the possibility of developing CRPS.

Type II complex regional pain syndrome of the hand resulting from repeated arterial punctures during transradial coronary intervention.

Coronary catheterization using a transradial approach has become a common procedure, as the risks of local complications are low and this procedure affords relatively expeditious postprocedural patient mobilization. Access site complications--such as radial artery spasm, hematoma, and compartment syndrome--have been reported in the literature; however, cases of complex regional pain syndrome (CRPS) of the hand related to the procedure are extremely rare. We describe a case of type II CRPS affecting the hand after a transradial coronary intervention that was complicated by repeated periprocedural arterial punctures. In this case, a 55-year-old woman underwent a percutaneous coronary intervention for the treatment of unstable angina. After successful completion of the procedure, the patient complained of severe pain along the median and radial nerve distributions and resulting disability of the right hand. Although subsequent duplex sonography showed no abnormalities, a nerve conduction study uncovered injury to multiple nerves on the right. A diagnosis of type II CRPS was then made and the patient was treated with a nerve block as well as multiple medical modalities. This case demonstrates a very unusual complication resulting from the transradial approach to percutaneous coronary intervention.

Visually evoked pain and its extinction using virtual reality in a patient with complex regional pain syndrome type II.

ABSTRACT: In this case report, we used virtual reality (VR) to explore pain evoked by only the appearance of being touched (rather than actually being touched) in a person with complex regional pain syndrome type II. Furthermore, we explored the degree to which this visually evoked pain could be extinguished by applying exposure principles in VR. In stage 1, we identified 4 specific scenarios where pain was triggered by visually simulated touch (without physical stimulation) and used these scenarios to quantify baseline sensitivity to visuotactile stimulation. In stage 2, the patient undertook a 12-week virtual exposure program, and the visual triggers were reassessed 3 weeks after the commencement and immediately upon completion of the program. At baseline, severe pain and a profound cold sensation were immediately and consistently evoked in concert with visually simulated touch. At 12-week follow-up, only one of the initially provocative visual stimuli triggered pain and only after 60 seconds of repeated stimulation. Unfortunately, the transfer of desensitisation from VR to the real world was limited. This case report describes the phenomena of visually evoked pain. Moreover, it describes the near complete extinguishing of visually evoked pain through virtual graded exposure. How improvements gained in VR might be better transferred to real-word improvements merits further investigation.

Motor cortex stimulation for trigeminal neuropathic or deafferentation pain: an institutional case series experience.

BACKGROUND: Trigeminal neuropathy is a rare, devastating condition that can be intractable and resistant to treatment. When medical treatment fails, invasive options are limited. Motor cortex stimulation (MCS) is a relatively recent technique introduced to treat central neuropathic pain. The use of MCS to treat trigeminal neuropathic or deafferentation pain is not widespread and clinical data in the medical literature that demonstrate efficacy are limited. METHOD: We retrospectively reviewed patients with trigeminal neuropathic or trigeminal deafferentation pain who were treated at the Oregon Health & Science University between 2001 and 2008 by 1 neurosurgeon using MCS. RESULTS: Eight of 11 patients (3 male, 8 female) underwent successful permanent implantation of an MCS system. All 8 patients reported initial satisfactory pain control. Three failed to experience continued pain control (6 months of follow-up). Five continued to experience long-term pain control (mean follow-up, 33 months). Average programming sessions were 2.2/year (all 8 patients) and 1.55/year (5 patients who sustained long-term pain control). Patients with anesthesia dolorosa or trigeminal deafferentation pain who had previously undergone ablative trigeminal procedures responded poorly to MCS. We encountered no perioperative complications. CONCLUSION: MCS is a safe and potentially effective therapy in certain patients with trigeminal neuropathy.

DREZotomy in the treatment of deafferentation pain: review of results and analysis of predictive factors for success. / Drezotomía en el tratamiento del dolor por desaferentización: revisión de resultados y análisis de factores predictores de éxito.

BACKGROUND AND OBJECTIVES: The treatment of deafferentation pain by spinal DREZotomy is a proven therapeutic option in the literature. In recent years, use of DREZotomy has been relegated to second place due to the emergence of neuromodulation therapies. The objectives of this study are to demonstrate that DREZotomy continues to be an effective and safe treatment and to analyse predictive factors for success. PATIENTS AND METHODS: A retrospective study was conducted of all patients treated in our department with spinal DREZotomy from 1998 to 2018. Bulbar DREZotomy procedures were excluded. A visual analogue scale (VAS) and the reduction of routine medication were used as outcome variables. Demographic, clinical and operative variables were analysed as predictive factors for success. RESULTS: A total of 27 patients (51.9% female) with a mean age of 53.7 years underwent DREZotomy. The main cause of pain was brachial plexus injury (BPI) (55.6%) followed by neoplasms (18.5%). The mean time of pain evolution was 8.4 years with a mean intensity of 8.7 according to the VAS, even though 63% of the patients had previously received neurostimulation therapy. Favourable outcome (≥50% pain reduction in the VAS) was observed in 77.8% of patients during the postoperative period and remained in 59.3% of patients after 22 months average follow-up (mean reduction of 4.9 points). This allowed for a reduction in routine analgesic treatment in 70.4% of them. DREZotomy in BPI-related pain presented a significantly higher success rate (93%) than the other pathologies (41.7%) (p=.001). No association was observed between outcome and age, gender, DREZ technique, duration of pain or previous neurostimulation therapies. There were six neurological complications, four post-operative transient neurological deficits and two permanent deficits. CONCLUSION: Dorsal root entry zone surgery is effective and safe for treating patients with deafferentation pain, especially after brachial plexus injury. It can be considered an alternative treatment after failed neurostimulation techniques for pain control. However, its indication should be considered as the first therapeutic option after medical therapy failure due to its good long-term results.

Complex regional pain syndrome type II associated with lumbosacral plexopathy: a case report.

INTRODUCTION: Complex regional pain syndrome (CRPS) is a well-known clinical entity, first described in the 1800s, consisting of pain, hyperalgesia, edema, and sudomotor changes either without (Type I) or with (Type II) a definable nerve injury. CRPS Type II is most commonly caused by high velocity missile injuries, mononeuropathies, and partial nerve transections. CASE REPORT: In this case, a 25-year-old soldier who sustained a blast injury causing multiple spinal compression fractures, extremity fractures, and pelvic and sacral fractures was transferred to a U.S. Army medical center for surgical management and rehabilitation. He complained of weakness, sensory changes, and pain in his left lower extremity. The patient also demonstrated swelling and hyperesthesia of the left foot and ankle. Undiagnosed soft tissue injury, fracture, and deep venous thrombosis were ruled out by imaging studies. The patient had an electromyogram/nerve conduction study (EMG/NCS) that showed widespread left sided lumbosacral plexopathy as well as possible cauda equina injury. Triple phase bone scan demonstrated findings consistent with CRPS of the left foot and ankle. He was started on a tricyclic antidepressant and an anticonvulsant. Physical and occupational therapy were quickly engaged to incorporate range of motion exercises, mirror therapy, and physical modalities. The patient continued conservative management and rehabilitation and eventually was discharged with significantly improved function and decreased pain. CONCLUSION: Although many causes of CRPS Type II have been described, this is only the second reported case of CRPS Type II secondary to lumbosacral plexopathy in the literature.

A possible case of complex regional pain syndrome in the orofacial region.

OBJECTIVE: To present a case of complex regional pain syndrome (CRPS) type II with sympathetic dysfunction and trophic changes in the orofacial region, which was partially responsive to intravenous ketamine. PATIENT: The patient was a 68-year-old man who suffered from inveterate pain with trophic changes of the right face and tongue and vasomotor dysfunction on the right side of the face after ipsilateral trigeminal nerve block. Allodynia and hyperalgesia were observed on the affected side of the face. Pain initially improved after sympathetic nerve block, but similar pain returned that was unresponsive to the same procedure. Repeated intravenous administration of low-dose ketamine preceded by intravenous midazolam alleviated the pain, but trophic changes of the tongue persisted. DISCUSSION: CRPS in the orofacial region has not been clearly defined and has been infrequently documented. Clinical findings in this patient met the criteria of the International Association for the Study of Pain's and Harden's diagnostic criteria for CRPS. The reason for gradual pain relief after induction of intravenous ketamine therapy was unclear, but the fact that only ketamine and not other various pain medicines or procedures alleviated the pain is important to note. CONCLUSION: Distinct cases of CRPS involving the orofacial region are rare. Thorough observations and documentation of signs and symptoms may lead to future standardization of diagnostic criteria and treatment strategies for this disorder.

Therapy Habituation at 12 Months: Spinal Cord Stimulation Versus Dorsal Root Ganglion Stimulation for Complex Regional Pain Syndrome Type I and II.

The ACCURATE randomized, controlled trial compared outcomes of dorsal root ganglion (DRG) stimulation versus tonic spinal cord stimulation (SCS) in 152 subjects with chronic lower extremity pain due to complex regional pain syndrome (CRPS) type I or II. This ACCURATE substudy was designed to evaluate whether therapy habituation occurs with DRG stimulation as compared to SCS through 12-months. A modified intention-to-treat analysis was performed to assess percentage pain relief (PPR) and responder rates at follow-up visits (end-of-trial, 1, 3, 6, 9, 12-months postpermanent implant) for all subjects that completed trial stimulation (DRG:N = 73, SCS:N = 72). For both groups, mean PPR was significantly greater at end-of-trial (DRG = 82.2%, SCS =0 77.0%) than all other follow-ups. Following permanent DRG system implantation, none of the time points were significantly different from one another in PPR (range = 69.3-73.9%). For the SCS group, PPR at 9-months (58.3%) and 12-months (57.9%) was significantly less than at 1-month (66.9%). The responder rate also decreased for the SCS group from 1-month (68.1%) to 12-months (61.1%). After stratifying by diagnosis, it was found that only the CRPS-I population had diminishing pain relief with SCS. DRG stimulation resulted in more stable pain relief through 12-months, while tonic SCS demonstrated therapy habituation at 9- and 12-months. Trial Registration: The ACCURATE study was registered at ClinicalTrials.gov with Identifier NCT01923285. PERSPECTIVE: This article reports on an ACCURATE substudy, which found that long-term therapy habituation occurred at 12-months with SCS, but not DRG stimulation, in patients with CRPS. The underlying mechanisms of action for these results remain unclear, although several lines of inquiry are proposed.

Practical management of complex regional pain syndrome.

Complex regional pain syndrome (CRPS) describes a diversity of painful conditions following trauma, coupled with abnormal regulation of blood flow and sweating, trophic changes, and edema of skin. The excruciating pain and diverse autonomic dysfunctions in CRPS are disproportionate to any inciting and recovering event. CRPS type I is formerly identified as "reflex sympathetic dystrophy." CRPS type II is the new term for "causalgia" that always coexists with documented nerve injury. The present diagnostic criteria of CRPS I and II depend solely on meticulous history and physical examination without any confirmation by specific test procedure (or gold standard). There are only few clinical studies with large-scale randomized trials of pharmacologic agents on the treatment of CRPS. Bisphosphonates have been studied in multiple controlled trials, based on theoretical benefit of bone resorption, to offer pain relief and functional improvement in patients with CRPS. Many current rationales in treatment of CRPS (such as topical agents, antiepileptic drugs, tricyclic antidepressants, and opioids) are mainly dependent on efficacy originate in other common conditions of neuropathic pain. There are additional innovative therapies on CRPS that are still in infancy. No wonder all the treatment of individual CRPS case nowadays is pragmatic at best. Although the interventional therapies in CRPS (such as nerve blockade, sympathetic block, spinal cord and peripheral nerve stimulation, implantable spinal medication pumps, and chemical and surgical sympathectomy) may offer more rapid response, yet it is still controversial with unpredictable outcome. Nevertheless, we need to start pain management immediately with the ambition to restore function in every probable case of CRPS. An interdisciplinary setting with comprehensive approach (pharmacologic, interventional, and psychological in conjunction with rehabilitation pathway) has been proposed as protocol in the practical management of CRPS. It is crucial to have a high sensitivity value combined with a fair specificity in revising diagnostic criteria of CRPS. The validation and consensus for new rationalized diagnostic criteria of CRPS could facilitate further research to enhance clinical outcome including quality of life. These endeavors to minimize suffering from CRPS would certainly be appreciated by many patients and their loved ones.

Peripheral median nerve stimulation for the treatment of iatrogenic complex regional pain syndrome (CRPS) type II after carpal tunnel surgery.

We report on the use and follow-up of direct peripheral nerve stimulation of the median nerve for the treatment of iatrogenic complex regional pain syndrome (CRPS). A 56-year-old woman presented with CRPS type II in the right forearm and hand, which had started after multiple carpal tunnel surgeries and had lasted for 2 years. The visual analogue scale (VAS) score was 8-10 out of 10. After a successful 15-day trial of median nerve peripheral nerve stimulation via a quadripolar lead in the right carpal tunnel space, an implantable pulse generator was inserted in the right infraclavicular space. The VAS score decreased to 1-2 out of 10 and the patient regained the ability to sleep. After 36 months of follow-up, the patient was still experiencing good pain relief without other treatment. We conclude that peripheral nerve stimulation is easy to use in pain management and could offer a valid treatment option for iatrogenic CRPS type II.

Risk Factors Associated with Lead Migration Requiring Revision in Dorsal Root Ganglion Stimulation.

BACKGROUND: Neuromodulation is an evolving therapy for chronic pain. Aiming to meet the limitations of traditional spinal cord stimulation, dorsal root ganglion (DRG) stimulation targets pain in a dermatomal distribution at the site of pain transmission. Despite these advantages, lead migration is a significant complication that hinders the long-term efficacy of DRG stimulation. This study aims to identify risk factors for lead migration requiring revision in DRG stimulation. METHODS: We performed a retrospective review of all subjects who had DRG stimulators implanted at T10-S2 by a single physician over a 2-year period. Their history was reviewed for the following: age, sex, diagnosis, lead placement, reported symptom relief, complications, and postoperative activity. RESULTS: In total, 19 cases of DRG stimulator implantation were identified. All patients reported pain relief, with 84.2% (16/19) describing >50% relief. In total, 31.6% of patients (6/19) developed lead migration and 15.8% of total implanted leads (9/57) migrated. Of the migrated leads, 4% (4/9) occurred at S1 and 33.3% (3/9) occurred at L4. The underlying etiology of lead migration was clear and preventable in 66.7% of patients (4/6). All patients who developed lead migration were women. CONCLUSIONS: Premature activity, hardware manipulation, and female sex appear to be associated with an increased risk for lead migration. Leads on the S1 and L4 locations may be more likely to migrate. Large trials are necessary to gain a more conclusive understanding of these risk factors for lead migration.

Mirror visual feedback alleviates deafferentation pain, depending on qualitative aspects of the pain: a preliminary report.

OBJECTIVES: Following lesions in somatosensory pathways, deafferentation pain often occurs. Patients report that the pain is qualitatively complex, and its treatment can be difficult. Mirror visual feedback (MVF) treatment can improve deafferentation pain. We sought to classify the qualities of the pain in order to examine whether the potential analgesic effect of MVF depends on these qualities. METHODS: Twenty-two patients with phantom limb pain, or pain related to spinal cord or nerve injury, performed a single MVF procedure. Before and after the MVF procedure, we evaluated phantom limb awareness, movement representation of the phantom or affected/paralysed limb, pain intensity on an 11-point numerical rating scale (0-10) and the qualities of the pain [skin surface-mediated (superficial pain) vs deep tissue-mediated (deep pain)] using lists of pain descriptors for each of the two categories. RESULTS: Fifteen of the patients perceived the willed visuomotor imagery of the phantom or affected/paralysed limb after the MVF procedure. In most of the patients, a reduction in pain intensity and a decrease in the reporting of deep-pain descriptors were linked to the emergence of willed visuomotor imagery. CONCLUSIONS: In this pilot study, we roughly classified the pain descriptor items into two types for evaluating the qualities of deafferentation pain. We found that visually induced motor imagery by MVF was more effective for reducing deep pain than superficial pain. This suggests that the analgesic effect of MVF treatment does depend on the qualities of the pain. Further research will be required to confirm that this effect is a specific consequence of MVF.

The outcome of percutaneous computed tomography-guided chemical lumbar sympathectomy for patients with causalgia after lumbar discectomy.

BACKGROUND: Coldness, numbness, or causalgia usually affects the lower limbs in patients after back surgeries. The treatment of causalgia is still the source of continuing debate. We treated patients presenting with causalgia secondary to LD with CT-guided CLS and determined the therapeutic outcome at long-term follow-up. METHODS: From January 2002 to December 2002, a total of 15 patients (16 limbs) with causalgia after LD underwent the percutaneous CT-guided CLS. There were 7 male patients and 8 female patients, with an average age of 49.1 years. A total of 14 patients underwent unilateral procedures, and 1 patient underwent staged bilateral procedures. We followed up our patients for at least 24 months (24-36 months). RESULTS: There were 13 patients (14 limbs) diagnosed as Drucker stage I and 2 patients as stage II. There were 88% (14 limbs) that had an early satisfactory outcome after CLS and 75% (12 limbs) that had a late satisfactory outcome (more than 24 months after CLS). Stage I patients had more satisfying early and late outcome than stage II patients (P= .014 and P= .039, respectively). Female patients were more likely to have satisfactory late outcome than male patients (P= .034). There was no operative mortality. A patient had a complication of genitofemoral neuralgia, which had recovered in a month. CONCLUSIONS: We concluded that the percutaneous CT-guided CLS is an easy, safe, and reproducible technique, and it carries long-term benefit to patients with pain after LD presenting with causalgia, especially for patients with Drucker stage I and female patients.