Gamma Knife Central Lateral Thalamotomy for Chronic Neuropathic Pain: A Single-Center, Retrospective Study.

BACKGROUND: Chronic neuropathic pain can be severely disabling and is difficult to treat. The medial thalamus is believed to be involved in the processing of the affective-motivational dimension of pain, and lesioning of the medial thalamus has been used as a potential treatment for neuropathic pain. Within the medial thalamus, the central lateral nucleus has been considered as a target for stereotactic lesioning. OBJECTIVE: To study the safety and efficacy of central lateral thalamotomy using Gamma Knife radiosurgery (GKRS) for the treatment of neuropathic pain. METHODS: We retrospectively reviewed all patients with neuropathic pain who underwent central lateral thalamotomy using GKRS. We report on patient outcomes, including changes in pain scores using the Numeric Pain Rating Scale and Barrow Neurological Institute pain intensity score, and adverse events. RESULTS: Twenty-one patients underwent central lateral thalamotomy using GKRS between 2014 and 2021. Meaningful pain reduction occurred in 12 patients (57%) after a median period of 3 months and persisted in 7 patients (33%) at the last follow-up (the median follow-up was 28 months). Rates of pain reduction at 1, 2, 3, and 5 years were 48%, 48%, 19%, and 19%, respectively. Meaningful pain reduction occurred more frequently in patients with trigeminal deafferentation pain compared with all other patients (P = .009). No patient had treatment-related adverse events. CONCLUSION: Central lateral thalamotomy using GKRS is remarkably safe. Pain reduction after this procedure occurs in a subset of patients and is more frequent in those with trigeminal deafferentation pain; however, pain recurs frequently over time.

Causalgia: a military pain syndrome.

Causalgia, officially known as complex regional pain syndrome type II, is a pain syndrome characterized by severe burning pain, motor and sensory dysfunction, and changes in skin color and temperature sensation distal to an injured peripheral nerve. The pain syndrome primarily tends to affect combat soldiers after they sustain wartime injuries from blasts and gunshots. Here, the authors provide a historical narrative that showcases the critical contributions of military physicians to our understanding of causalgia and to the field of peripheral nerve neurosurgery as a whole.

Gamma Knife radiosurgery for the treatment of cluster headache: a systematic review.

Cluster headache (CH) is a severe trigeminal autonomic cephalalgia that, when refractory to medical treatment, can be treated with Gamma Knife radiosurgery (GKRS). The outcomes of studies investigating GKRS for CH in the literature are inconsistent, and the ideal target and treatment parameters remain unclear. The aim of this systematic review is to evaluate the safety and the efficacy, both short and long term, of GKRS for the treatment of drug-resistant CH. A systematic review of the literature was performed to identify all clinical articles discussing GKRS for the treatment of CH. The literature review revealed 5 studies describing outcomes of GKRS for the treatment of CH for a total of 52 patients (48 included in the outcome analysis). The trigeminal nerve, the sphenopalatine ganglion, and a combination of both were treated in 34, 1, and 13 patients. The individual studies demonstrated initial meaningful pain reduction in 60-100% of patients, with an aggregate initial meaningful pain reduction in 37 patients (77%). This effect persisted in 20 patients (42%) at last follow-up. Trigeminal sensory disturbances were observed in 28 patients (58%) and deafferentation pain in 3 patients (6%). Information related to GKRS for CH are limited to few small open-label studies using heterogeneous operative techniques. In this setting, short-term pain reduction rates are high, whereas the long-term results are controversial. GKRS targeted on the trigeminal nerve or sphenopalatine ganglion is associated to a frequent risk of trigeminal disturbances and possibly deafferentation pain.

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

Antecedentes y objetivos El tratamiento del dolor por desaferentización mediante drezotomía espinal es una opción terapéutica contrastada en la literatura. En los últimos años, la drezotomía ha visto relegado su empleo a un segundo plano debido a la eclosión de las terapias neuromoduladoras. Los objetivos de este estudio son demostrar que la drezotomía continúa siendo un tratamiento efectivo y seguro, y analizar aquellos factores predictores de éxito. Pacientes y métodos Se realizó un estudio retrospectivo de todos los pacientes tratados en nuestro servicio mediante drezotomía espinal desde 1998 hasta 2018. Se excluyeron los casos de drezotomía bulbar. Se emplearon la escala visual analógica (EVA) y la reducción de la medicación habitual como variables resultado, y se analizaron variables demográficas, clínicas y quirúrgicas como factores predictores de éxito. Resultados Un total de 27 pacientes (51,9% mujeres) de 53,7 años de edad media fueron tratados mediante drezotomía. La etiología principal del dolor fue por avulsión de plexo braquial (55,6%) seguida de causa tumoral (18,5%). El tiempo medio de evolución del dolor fue de 8,4 años con una intensidad media de 8,7 según la EVA, pese a que el 63% de los pacientes habían recibido tratamiento neuroestimulador previo. Durante el postoperatorio inmediato un 77,8% de los pacientes presentaron una reducción del 50% o más en la EVA. Tras un seguimiento medio de 22 meses posdrezotomía, permaneció una reducción de al menos el 50% en la EVA en el 59,3% de los pacientes (reducción media de 4,9 puntos) permitiendo una reducción del tratamiento analgésico habitual en el 70,4% de ellos. La drezotomía en la avulsión de plexo braquial presentó una tasa de éxito (93%) superior al resto de patologías (41,7%) de manera significativa (p = 0,001) (AU)

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 (AU)

Complex regional pain syndrome type II arising from a gunshot wound (GSW) associated with infective endocarditis and aortic valve replacement.

A 34-year-old man with a history of gunshot wound (GSW) to the right upper chest developed secondary aortic valve endocarditis (AVE) and was treated with an artificial valve placement (AVP). Three months after, he presented to an outpatient pain management clinic right arm pain and was diagnosed with complex regional pain syndrome type II (CRPS II). The patient underwent a diagnostic sympathetic ganglion block, before undergoing endoscopic thoracic sympathectomy surgery. Successful outcomes revealed decreased pain, opioid utilisation and improved tolerance to therapy and activities of daily living. To our knowledge, this is the first case reporting CRPS II arising from a GSW complicated by AVE followed by AVP, which emphasises how unforeseen syndromes can arise from the management of seemingly unrelated pathology. This case demonstrates the importance of timely and proper diagnosis of uncharacterised residual pain status post-trauma and differential diagnosis and management of chronic pain syndromes.

Predictors of Long-Term Outcome of Thoracic Sympathectomy in Patients with Complex Regional Pain Syndrome Type 2.

BACKGROUND AND OBJECTIVE: Long-term results of sympathectomy in patients with complex regional pain syndrome (CRPS) type 2 varies widely among studies due to nonspecific or vague criteria of diagnosis and absence of outcome predictors that help good patient selection. The objective was to determine the predictors of long-term outcome of sympathectomy in patients with upper limb CRPS type 2. METHODS: A retrospective cohort, in which those who underwent thoracic sympathectomy for upper limb CRPS type 2 from 2007 to 2014, were included. Demographic and clinical data of patients, in addition to stellate ganglion block (SGB) details and percent of pain relief at the end of follow-up, were collected and used for statistical analysis. RESULTS: Our study included 53 patients, with a mean age of 47 ± 7 years, and 60% females. Using bivariate correlations; age, sex, nerve injured, type of injury, and occupation were not significantly correlated to outcome. Multiple linear regression analysis of correlated variables revealed that duration of pain relief after SGB and degree of sympathetic overactivity were positive predictors (ß = 0.286, P = 0.027, and ß = 0.257, P = 0.003, respectively), whereas presence of allodynia was a negative predictor (ß = -0.280, P = 0.041) of the final pain relief. Final pain relief was better in those patients who experienced extended relief of their pain >2 days after SGB (P = 0.001, Kruskal Wallis test). CONCLUSIONS: Thoracic sympathectomy may prove more effective than reported in carefully selected CRPS patients with prominent sympathetic overactivity, no or early allodynia, and pain relief >2 days after SGB.

El papel de la simpatectomía lumbar en la cirugía vascular actual / The current role of lumbar sympathectomy in vascular surgery

La simpatectomía lumbar es una técnica quirúrgica que gozó de gran popularidad para el tratamiento de la enfermedad vascular periférica, sobre todo antes del desarrollo de las técnicas reconstructivas arteriales. Desde entonces, su papel ha ido reduciéndose paulatinamente. En los últimos años, y condicionado por el desarrollo de las técnicas endovasculares específicas para el sector infragenicular, se realiza en pocas ocasiones en nuestro país. Siendo la tasa de complicaciones baja, la aparición de técnicas menos agresivas, como la simpatectomía lumbar química o la retroperitoneoscópica ha disminuido la estancia hospitalaria y el periodo de recuperación. Aun así, la evidencia sobre su beneficio en la isquemia crónica de extremidades inferiores es escasa y basada en artículos de baja calidad metodológica. Los estudios existentes no han podido demostrar beneficios objetivos ni superioridad frente a otros tratamientos farmacológicos, quedando su papel muy limitado a algunos pacientes muy seleccionados en los que la indicación es discutible. Los avances en los tratamientos farmacológicos del vasoespasmo y de la causalgia también han limitado sus indicaciones en estas patologías

Lumbar sympathectomy was a very popular technique for the treatment of peripheral vascular disease, especially before the development of the arterial reconstructive techniques. Since then, its role has been gradually decreasing. In the last few years, due to the development of endovascular techniques for the infrapopliteal occlusive disease, it is rarely performed in our country. Having low complications rates, the emergence of less invasive techniques, like chemical or retroperitoneoscopic lumbar sympathectomy, has decreased the in-hospital stay and the recovery period. Even so, the evidence of its benefit on lower limb ischemia is poor, and based on low quality reports. Available studies have failed to demonstrate objective benefits or superiority over pharmacotherapy, with the role of sympathectomy being limited to a few carefully selected patients, in which indication is controversial. Advances in pharmacotherapy of vasospasm and causalgia have also limited its role in these pathologies

Nerve resection, crush and re-location relieve complex regional pain syndrome type II: a case report.

This case report describes the remarkable recovery of a patient with very long-standing, medically intractable and disabling, lower-limb, complex regional pain syndrome type II following the resection, crushing, and relocation of sensory nerves.

[Pronounced symptom deterioration in complex regional pain syndrome type II after isolated application of a highly concentrated capsaicin patch. A case report]. / Ausgeprägte Symptomverschlechterung bei CRPS Typ II nach einmaliger Applikation eines hochprozentigen Capsaicinpflasters. Ein Fallbericht.

Topical 8 % capsaicin is an established therapeutic option for the treatment of peripheral neuropathic pain. In accordance with the internationally accepted definition, complex regional pain syndrome (CRPS) type II is a form of neuropathic pain so that capsaicin plasters represent a treatment option. However, for the treatment of CRPS it is recommended that painful stimuli should be avoided but capsaicin induces a strong nociceptive stimulation and so its use is at present controversial. We report on the course of such an application in a patient who developed CRPS type II with intractable neuropathic pain after hallux surgery. As a result of a single treatment with capsaicin a pronounced recurrence developed with central nervous symptoms.

Surgical treatment of complex regional pain syndrome type II with regional subcutaneous venous sympathectomy.

BACKGROUND: The effectiveness of a new surgical technique for the treatment of severe chronic pain stages was evaluated. For the last 140 years, the treatment of complex regional pain syndrome type II (CRPS II) has been an unsolved problem. Therapeutic approaches have included conventional pain medication, physical therapy, sympathetic blocks, transcutaneous or spinal cord stimulation, injections or infusion therapies, and sympathectomy. When used alone or in combination, these therapies often yield unfavorable results. The majority of physicians who treat patients with CRPS are convinced that a surgical treatment of the affected extremity only exacerbates the symptoms, especially its hallmark excruciating pain. METHODS: Sixteen patients with a CRPS type II of the upper or lower limb were included in the study after ineffective pain therapy for more than 6 months. The most proximal region of pain associated with CRPS was localized, and 2% lidocaine was injected into that area. Once the sympathetic, deep, burning pain had been blocked, the subcutaneous veins in the previously determined area were surgically removed. A visual analog scale, the Nottingham Health Profile, and physical examinations were used to evaluate the outcome of the operation. RESULTS: Twelve (75%) surgically treated patients showed significant improvement in limb function, the visual analog scale, and the Nottingham Health Profile. CONCLUSIONS: These data and recent findings in animal models conclude that CRPS type II is maintained by a coupling of newly sprouted sympathetic and sensible fibers. These fibers can be resected with a regional subcutaneous venous sympathectomy. LEVEL OF EVIDENCE: Therapeutic study, level III.

Treatment of neuropathic deafferentation pain using DREZ lesions; long-term results.

INTRODUCTION: Deafferentation pain secondary to spinal cord injury, brachial plexus avulsion and other peripheral nerve injuries is often refractory to conventional treatments. This study evaluates the long-term efficacy of spinal DREZ (Dorsal Root Entry Zone) lesions for the treatment of neuropathic pain syndromes caused by deafferentation. PATIENTS AND METHODS: A series of 18 patients with refractory deafferentation pain treated with radiofrequency DREZ lesions is presented. The immediate and long-term efficacy was measured with the Visual Analogue Scale (VAS) before and after treatment, the patient's subjective evaluation, the percentage of patients returning to work and the reduction in pain medication. RESULTS: Pain on the VAS significantly decreased from 8.6 preoperatively to 2.9 (p<.001) at discharge. Over the long-term, with a mean follow-up of 28 months (6-108) pain remained at 4.7 on the VAS (p<0.002). The percentage of patients with moderate to excellent pain relief was 77% at discharge and 68% at the last follow-up. Pain medication was reduced in 67% of the patients and 28% returned to work. The best results were obtained in patients with brachial plexus avulsion, with a significant long-term pain relief in all cases. CONCLUSIONS: Radiofrequency DREZ lesion is an effective and safe treatment for refractory neuropathic pain caused by deafferentation.

Causalgia: a restatement.

Forty-eight cases of causalgia are described. The syndrome was caused by missile injury in 33 patients. There was a major arterial injury in 22 patients. Sympathetic block followed by sympathectomy abolished the pain in 11 of the first 14 patients in the series. Causalgia was cured by correcting the lesion of the nerve and of the adjacent axial artery in the subsequent 32 patients. The concept of complex regional pain syndrome Type 1 and Type 2 is challenged.

Dorsal root entry zone coagulation for treatment of deafferentation pain syndromes.

BACKGROUND: Deafferentation pain is a kind of chronic pain syndrome and hard to manipulate. To evaluate the effectiveness and safety of junctional dorsal root entry zone (DREZ) coagulation, 23 consecutive patients with intractable deafferentation pain syndrome were studied. METHODS: Twenty-three patients underwent junctional DREZ coagulation (C5-T1 for upper extremities and L2-S1 for lower extremities) under general anesthesia. The pain severity was evaluated by the short McGill pain questionnaire (MPQ) and the visual analog scale (VAS), and the depression and anxiety of patients were assessed by Hamilton rating scale for depression (HRSD), Hamilton anxiety scale (HAMA), self-rating anxiety scale (SAS) and self-rating depression scale (SDS). RESULTS: All the patients experienced significant pain reduction immediately after surgery. The scales of short MPQ and VAS at pre-operation, 6-month and 12-month follow-up were 31.5 +/- 3.4 and 8.8 +/- 1.5, 6.5 +/- 1.9 and 2.5 +/- 2.2, 7.1 +/- 2.1 and 2.9 +/- 1.9, respectively. The postoperative scores comparing to pre-operative scores showed a statistically significant difference (P < 0.01). The depression and anxiety state was also significantly relieved. At 12-month follow-up 6 patients had complete pain relief, 11 had excellent results with more than 75% pain relief, 17 had good results with more than 50% pain relief (73.9%). The main postoperative complications were transient slight hemiplegia (8), hypesthesia and paresthesia (15), a bearing down feeling of affected extremity (6), and deep sensory disability in the lower limbs (4) on the operated side. Because of the long time and prone position of the operation, 13 cases had a transient hyperalgesia in the upper chest. CONCLUSION: DREZ coagulation is a safe and effective procedure in the treatment of deafferentation pain syndromes.

Nerve resection and re-location may relieve causalgia: a case report.

This article reports the relief of severe causalgia of the right infra-orbital nerve by nerve section and re-location in a 14-year-old boy who had worsening neuropathic pain (NP) and was housebound and refractory to all analgesics for 14 months. His infra-orbital nerve was sectioned and re-located into his buccal fat pad. Severe steady burning, electric shock-like pain and allodynia disappeared and he was able to return to school and an increasingly normal life at one year post-operatively and is pain-free at 3 years and 6 months of follow-up. With NP further deafferentation can cause a worsening of the pain or anaesthesia dolorosa. In this instance there was dramatic and then sequential, gradual and complete resolution of all components of this particular form of NP. Therefore, in selected patients with causalgia this nerve re-location technique may help in symptom resolution and improve quality of life.

Stimulation of primary motor cortex for intractable deafferentation pain.

The stimulation of the primary motor cortex (M1) has proved to be an effective treatment for intractable deafferentation pain. This treatment started in 1990, and twenty-eight studies involving 271 patients have been reported so far. The patients who have been operated on were suffering from post-stroke pain (59%), trigeminal neuropathic pain, brachial plexus injury, spinal cord injury, peripheral nerve injury and phantom-limb pain. The method of stimulation was: a) epidural, b) subdural, and c) within the central sulcus. Overall, considering the difficulty in treating central neuropathic pain, trigeminal neuropathic pain and certain types of refractory peripheral pain, the electrical stimulation of M1 is a very promising technique; nearly 60% of the treated patients improved with a higher than 50% pain relief after several months of follow-up and sometimes of a few years in most reports. The mechanism of pain relief by the electrical stimulation of M1 has been under investigation. Recently, repetitive transcranial magnetic stimulation (rTMS) of M1 has been reported to be effective on deafferentation pain. In the future, rTMS may take over from electrical stimulation as a treatment for deafferentation pain.

Deafferentation pain resulting from cervical posterior rhizotomy is alleviated by chromaffin cell transplants into the rat spinal subarachnoid space.

OBJECTIVE: Deafferentation pain is common after posttraumatic brachial plexus avulsion in humans. Alleviation of such pain is poorly achieved by most therapeutic interventions; the only efficient neurosurgical procedure currently available is lesioning of the dorsal root entry zone. Previous work has demonstrated that adrenal medullary transplants into the lumbar spinal subarachnoid space can alleviate neuropathic pain behavior resulting from peripheral nerve or spinal cord injury. The purpose of this study was to evaluate the potential effects of adrenal medullary transplants on brachial plexus deafferentation pain. METHODS: The cervical posterior rhizotomy model was selected as an upper segmental deafferentation model because it mimics the pathological situation after traumatic brachial plexus avulsion in humans. Animals underwent a right posterior cervical rhizotomy extending from C5 to T1 and received either adrenal medullary transplants or control striated muscle transplants into the cervical subarachnoid space. The clinical evolution was evaluated daily for self-directed behaviors indicative of ongoing pain, including onset, dermatomal extent, and severity. RESULTS: In animals with muscle control transplants, self-directed behaviors appeared in 83.3% of the group, with a mean delay between rhizotomy and onset of self-directed behaviors of 8 days. In contrast, only 30.8% of the animals implanted with chromaffin cells exhibited any signs of self-directed behaviors, and these had a mean onset delay of 14 days. CONCLUSION: The suppression of self-directed behaviors by adrenal medullary transplants is similar to that observed after dorsal root entry zone lesioning and suggests that this approach may offer a nonablative alternative in the management of deafferentation pain resulting from dorsal root avulsion.

Microcoagulation of junctional dorsal root entry zone is effective treatment of brachial plexus avulsion pain: long-term follow-up study.

AIM: To analyze long-term clinical results of coagulation lesions of the dorsal root entry zone (DREZ) in patients with deafferentation pain due to brachial plexus avulsion and to correlate the pain relief after DREZ coagulation with pain duration before the DREZ coagulation. METHODS: Twenty-six patients with intractable deafferentation pain after brachial plexus avulsion lesion were treated for pain at the Department of Neurosurgery. Junctional coagulation lesion was made with bipolar forceps along the DREZ. The patients assessed post-operative analgesic effect using a visual analog scale at 1 week, 1 year, 3 years, and 5 years after the surgery. RESULTS: The greatest pain relief was reported immediately after the DREZ procedure. Over the 5-year follow-up period, the pain relief effect gradually and significantly decreased. There were no significant differences between the pain relief evaluated at 1 week and after 1 year and between the pain relief evaluated at 1 week and after 3 years. There was a correlation between the pain duration before the surgery and pain relief after the surgery, with best correlation found between pain duration before surgery and pain relief 5 years after DREZ procedure (r = 0.623, P = 0.007). CONCLUSION: The long-term follow up showed that the pain relief gradually decreased over 5 years after surgery. However, the pain relief still did not significantly decrease after 3 years.

Stimulation of primary motor cortex for intractable deafferentation pain.

To treat intractable deafferentation pains, we prefer stimulation of the primary motor cortex (M1). The methods of stimulation we utilize are electrical stimulation and repetitive transcranial magnetic stimulation (rTMS). In our department, we first attempt rTMS, and if this rTMS is effective, we recommend the patient to undergo procedures for motor cortex stimulation (MCS). A 90% intensity of resting motor threshold setting is used for rTMS treatment. In this study ten trains of 5 Hz rTMS for 10 seconds (50 seconds resting interval) were applied to the M1, S1, pre-motor and supplementary motor areas. Only M1 stimulation was effective for pain reduction in 10 of 20 patients (50%). Twenty-nine MCS procedures were performed by subdural implantation of electrodes, and in the case of hand or face pain, electrodes were implanted within the central sulcus (11 cases), because the main part of M1 is located in the central sulcus in humans. The success rate of MCS was around 63%, and seemed to be higher in cases of pain with spinal cord and peripheral origins, while it was lower in cases of post-stroke pain.