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 Table of Contents  
Year : 2021  |  Volume : 35  |  Issue : 1  |  Page : 75-78

Pulsed radiofrequency lesioning of the lumbosacral dorsal root ganglion in a patient with lumbosacral plexopathy due to locally advanced pelvic liposarcoma

1 Department of Anaesthesia and Pain Management, Sree Balaji Medical College and Hospital, BIHER, Chennai, Tamil Nadu, India
2 Department of Radiation Oncology, Sree Balaji Medical College and Hospital, BIHER, Chennai, Tamil Nadu, India
3 Department of Clinical Research, Apollo Proton Cancer Centre, Sree Balaji Medical College and Hospital, BIHER, Chennai, Tamil Nadu, India
4 Department of Anesthesiology and Pain Medicine, Sree Balaji Medical College and Hospital, BIHER, Chennai, Tamil Nadu, India

Date of Submission20-Oct-2020
Date of Decision26-Jan-2021
Date of Acceptance27-Jan-2021
Date of Web Publication27-Apr-2021

Correspondence Address:
Dr. Anand Murugesan
Department of Anaesthesia and Pain Management, Apollo Proton Cancer Centre, Taramani, Chennai, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijpn.ijpn_145_20

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Neoplastic lumbosacral plexopathy can be associated with pelvic malignancies where patients present with severe lumbosacral radicular pain (LSP) involving the lower extremities, leading to weakness of the affected limb. We hereby report the case of a 34-year male who presented with pain in low back radiating to left lower limb for the past 2 months. MR imaging, histopathological examination after debulking surgery confirmed it as a liposarcoma involving the anterior aspect of the left side of sacrum extending toward left neural foramina of S1-S2, left greater sciatic notch and left piriformis muscle. As the LSP was refractory to previous neuropathic medications it was planned to perform pulsed radiofrequency lesioning (PRFL) of lumbosacral Dorsal root ganglion (DRG) from L3 to S1 before further oncological management. Each DRG was treated with PRFL at 42°C for 120 s. Postprocedure, the patient had a satisfactory pain relief and underwent further oncological management.

Keywords: Dorsal root ganglion, liposarcoma, lumbosacral, neuropathy, pulsed radiofrequency

How to cite this article:
Murugesan A, Daivam I, Nangia S, Burela N, Panda PK, Raghuraman M S. Pulsed radiofrequency lesioning of the lumbosacral dorsal root ganglion in a patient with lumbosacral plexopathy due to locally advanced pelvic liposarcoma. Indian J Pain 2021;35:75-8

How to cite this URL:
Murugesan A, Daivam I, Nangia S, Burela N, Panda PK, Raghuraman M S. Pulsed radiofrequency lesioning of the lumbosacral dorsal root ganglion in a patient with lumbosacral plexopathy due to locally advanced pelvic liposarcoma. Indian J Pain [serial online] 2021 [cited 2021 Sep 24];35:75-8. Available from: https://www.indianjpain.org/text.asp?2021/35/1/75/314689

  Introduction Top

Neuropathy due to cancer is a well-known phenomenon and can occur by direct extension, hematogeneous spread, meningeal dissemination, lymphatic spread or as a paraneoplastic syndrome.[1] Neoplastic lumbosacral plexopathy occurs with a known primary malignancy or pelvic metastatic disease where the patients present with severe neuropathic pain radiating from the low back down to the lower extremities, and this progresses to weakness of the affected limb. Liposarcomas are malignant tumors of mesenchymal origin (adipose tissue) arising predominantly from the extremities, retroperitoneum, pelvis, and inguinal region. Epidural steroid injections are commonly performed for lumbosacral radicular pain (LSP) of any cause but are not effective in all patients and have several limitations to their use. Pulsed radiofrequency of dorsal root ganglion (PRF-DRG) is potentially an effective treatment for LSP.[2]

  Case Report Top

A 34-year-old male presented with complaints of pain in low back radiating to left lower limb for the past 2 months. There was numbness in the left great toe. He was unable to walk due to severe pain in the left lower limb and his pain score was visual analog scale (VAS) 9/10. He was on oral gabapentin 600 mg, duloxetine 40 mg, tapentadol 100 mg/day for the pain. MRI spine with pelvis was done 2 months ago which revealed a large mass in the anterior aspect of left side of sacrum extending towards left neural foramina of S1-S2, left greater sciatic notch, and left piriformis muscle. He underwent debulking surgery for the same and the specimen was sent for histopathological evaluation. The clinical details of the patient were discussed in our tumor board and the histopathology reviewed. The histopathological report confirmed well-differentiated liposarcoma. He was advised radiotherapy to the gross residual disease with margins, using intensity-modulated proton therapy (IMPT). The LSP was refractory to the neuropathic medications mentioned above and hence planned for pulsed radiofrequency lesioning (PRFL) of lumbosacral DRGs from L3 to S1 before IMPT.

After obtaining informed procedural consent, he was shifted inside operation room and positioned prone with continuous vital monitoring. His low back was prepared with povidone iodine and draped. Under local anesthesia infiltration and with fluoroscopic guidance, using 21 G, 10 mm active tip radiofrequency (RF)-cannula the left-sided DRG of L3 to S1 nerve roots reached. On fluoroscopy, this corresponded to the dorsal-cranial quadrant of the intervertebral foramen on lateral view [Figure 1] and on anteroposterior view, the tip was located midway into the pedicle column [Figure 1]. In case of S1 nerve root treatment, the electrode was advanced through the posterior foramen [Figure 2] with the target being the segmental nerve as it passes ventrally though the anterior sacral foramina; this is because of the inaccessibility of the DRG. The tip was advanced anterior to the anterior border of the sacral canal on lateral projection [Figure 3]. Nonionic contrast (iohexol) was injected to outline the contour of the DRG to confirm the target [Figure 1]. Once the electrode was appropriately positioned, the stylet was then replaced by the RF probe. The final positional requirements were as follows: (1) Sensory stimulation (50 Hz) threshold under 0.6 volts that created paresthesia concordant to the respective nerve root dermatomal distribution (2) Motor stimulation (2 Hz) was >1.5 times the sensory stimulation threshold. (3) Impedances were checked to ensure a complete electrical circuit and range from 200 to 400 Ohm. Each DRG was treated with PRFL at 42°C for 120 s [Figure 4]. PRFL was done without prior injection of local anesthetic onto the respective DRG. Post procedure after 1 h, the pain decreased dramatically to VAS 0/10. After the successful LSP relief, the patient is subjected to IMPT to gross disease in left side pelvis with 60 Gy in 33 fractions for a total duration of 39 days. The patient is on follow-up for the past 11 months and he has good pain relief VAS 2/10.

Figure 1: The electrode tip is in cephalo-posterior quadrant of the intervertebral foramen in lateral view and medial to mid-pedicular line in anteroposterior view

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Figure 2: The electrode was advanced through the S1 posterior foramen in ipsilateral oblique view

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Figure 3: The electrode tip was advanced anterior to the anterior border of the sacral canal on lateral view

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Figure 4: The pulsed radiofrequency lesioning settings in radiofrequency ablator

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  Discussion Top

Liposarcomas are the most common subtype of all soft-tissue sarcomas. Although liposarcomas may arise in any region of body that contains fat, coexisting primary intra-abdominal, and pelvic liposarcomas are uncommon.[3] Round cell liposarcoma variant is regarded as a histologic progression of pure myxoid liposarcoma to hypercellular round cell morphology. Myxomatous round cell liposarcomas (MRLS) may behave aggressively.[4] Surgery resection is the standard of care for MRLS patients with localized disease, but complete surgical resection is achieved in <70% of these patients due to close proximity to vital organs. About 25% of patients will develop metastatic distant disease after successful treatment of their primary tumor. Patients with giant round cell liposarcoma (tumors >10 cm) have a high risk of recurrence and metastasis.[3]

Jaeckle et al., in a series of 30 patients with neoplastic lumbosacral plexopathy,[5] severe, unrelenting pain, was an early and persistent symptom. The pain was neuropathic with deep aching, allodynic, and radicular in type. The symptoms were often initially mistaken for lumbosacral disk disease. Neurological signs were unilateral in 90% of the cases. Neoplastic lumbosacral radiculoplexopathy most commonly results from spread of local disease, whether from the primary tumor or metastatic foci adjacent to the plexus.[5],[6] Symptomatic management with analgesics and muscle relaxants is usually provided. Analgesics include nonsteroidal anti-inflammatory drugs, pregabalin, gabapentin, duloxetine, amitriptyline, and opioids.

The DRG is located between the dorsal root and the spinal nerve. It contains pseudo unipolar neurons that convey sensory information from the periphery to the CNS. Following nerve injury or inflammation, these neurons may become an important source of increased nociceptive signaling through increased neuronal excitability and generation of ectopic discharges.[7],[8] This provides an excellent opportunity for the lesioning of DRG neurons to prevent the development of these pathological discharges and also to treat the neuropathic pain due to radiculoplexopathies.

PRFL has gained popularity in the treatment of radicular pain including acute and chronic lumbar radicular pain of any cause in the last three decades.[9],[10],[11] All of these small studies have suggested the safety and potential efficacy in the treatment of lumbosacral root pain using PRFL, emphasizing its nondestructive nature. However, it is used only in a few centers in developing countries. Although a few case reports or case series regarding applications of PRFL for LSP are available in the literature, to the best of our knowledge, this case report has the following unique features: (1) Locally invasive malignant tumor in the pelvic region making the procedure technically more difficult than on a metastatic lesion that too at multiple levels (L3-S1). (2) PRFL used for the purpose of proton therapy. Because of the very good quality pain relief, the patient could cooperate for the proton therapy where even the slightest movement of the patient would make the therapy very difficult/impossible. (3) Following up the patient for more than a year, in an Indian setting, thereby assuring its safety on long-term basis, besides the dramatic short-term pain relief.

In PRFL serial bursts of 20 ms each of an alternating current are delivered. The oscillating frequency of the alternating current is 500,000 Hz. During one cycle the “active” phase of 20 ms is followed by a silent period of 480 ms to allow for washout of the generated heat. The output is usually set at 45 volts, but if the electrode tip temperature exceeds 42°C, it is decreased to prevent cell damage. This temperature is selected based on the findings that necrosis in various soft tissue cell lines could only be induced by heating to >43°C.[12],[13] In this patient, we were unable to detect neurological deficits or adverse painful side effects from PRFL. These findings are consistent with the previous observations of Van Zundert et al.[14] in which PRFL was applied to the cervical DRG. The mechanism of action of PRFL remains poorly understood and the technique is likely not entirely without tissue injury as once thought. It is at present hypothesized that PRFL induces changes in c-fos gene expression in the dorsal horn (Lamina I and II)[15] causing pain neuromodulation.

The use of continuous RF lesioning at 67°C adjacent to the DRG for the management of cervicobrachial pain has been investigated in two randomized controlled trials.[16],[17] Van Kleef et al. compared the efficacy of RF at 67°C with sham intervention and found a significant reduction in pain intensity 8 weeks after the intervention. Slappendel et al. found no difference in outcome when RF treatment with an electrode tip temperature of 40°C was used as compared with RF at 67°C. For that reason, a nondestructive or minimally destructive technique would be more attractive.

Complications from PRFL interventions (sacroiliac treatment, DRG neurotomy, and intradiscal PRF) are exceedingly rare. Most side effects such as local swelling, pain at the site of the needle insertion and pain in the extremities are short lived and self-limited. More serious complications may include neural trauma, injection into vessels, hematoma formation, and sciatic nerve injury.[18]

There are concerns about using PRFL in children because of the potential risks of nerve injury that may cause a permanent loss of function at an early age. However, several studies in adults have reported the safety of this technique making this treatment attractive. The decision to perform this procedure despite limited previous experience in children can be considered due to the low risk potential and the possible benefits of avoiding polypharmacy, particularly opioids. Procedural interventions in pediatrics are generally performed with scarce evidence and based on adult experience. The positive results of this case report suggest that PRFL may be effective in children and could be considered if the potential benefits outweigh the risks when noninvasive treatments fail.[19]

Pain from neoplastic lumbosacral plexopathy sometimes is resistant to conventional pain treatment. According to an old review of destructive procedures for cancer pain, only cordotomy has been reported to play an important role in the treatment of cancer pain. Until 2014, the effectiveness of dorsal rhizotomy, which selectively interrupts pain transmission, has not been shown in neoplastic lumbosacral plexopathy. Dorsal rhizotomies of the involved segments were performed on patients in whom neuropathic pain from lumbosacral plexus involvement in terminal pelvic cancer had been refractory to other therapies.[20]

  Conclusion Top

Based on the findings of this case report, we found that PRFL of the DRG of lumbosacral nerve roots appears to be a useful, effective and safe treatment for neoplastic lumbosacral radiculoplexopathy at multiple levels in a locally invasive malignant tumor for both short-term and long-term benefits.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initial s will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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Fletcher CD, Unni KK, Mertens F. World Health Organization Classification of Tumours: Pathology and Genetics of Tumours of Soft Tissue and Bone. Lyon: IARC Press; 2002.  Back to cited text no. 4
Jaeckle KA, Young DF, Foley KM. The natural history of lumbosacral plexopathy in cancer. Neurology 1985;35:8-15.  Back to cited text no. 5
Thomas JE, Cascino TL, Earle JD. Differential diagnosis between radiation and tumor plexopathy of the pelvis. Neurology 1985;35:1-7.  Back to cited text no. 6
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Teixeira A, Grandinson M, Sluijter ME. Pulsed radiofrequency for radicular pain due to a herniated intervertebral disc – An initial report. Pain Pract 2005;5:111-5.  Back to cited text no. 10
Munglani R. The longer term effect of pulsed radiofrequency for neuropathic pain. Pain 1999;80:437-9.  Back to cited text no. 11
Yonezawa M, Otsuka T, Matsui N, Tsuji H, Kato KH, Moriyama A, et al. Hyperthermia induces apoptosis in malignant fibrous histiocytoma cells in vitro. Int J Cancer 1996;66:347-51.  Back to cited text no. 12
Hildebrandt B, Wust P, Ahlers O, Dieing A, Sreenivasa G, Kerner T, et al. The cellular and molecular basis of hyperthermia. Crit Rev Oncol Hematol 2002;43:33-56.  Back to cited text no. 13
Van Zundert J, Lamé IE, de Louw A, Jansen J, Kessels F, Patijn J, et al. Percutaneous pulsed radiofrequency treatment of the cervical dorsal root ganglion in the treatment of chronic cervical pain syndromes: A clinical audit. Neuromodulation 2003;6:6-14.  Back to cited text no. 14
Higuchi Y, Nashold BS Jr, Sluijter M, Cosman E, Pearlstein RD. Exposure of the dorsal root ganglion in rats to pulsed radiofrequency currents activates dorsal horn Lamina I and II neurons. Neurosurgery 2002;50:850-5.  Back to cited text no. 15
Van Kleef M, Lousberg R, Liem L, Barendse G, Kessels F, Sluijter M. Radiofrequency lesion adjacent to the dorsal root ganglion for cervicobrachial pain: A prospective double blind randomized study. Neurosurgery 1996;38:1127-32.  Back to cited text no. 16
Slappendel R, Crul BJ, Braak GJ, Geurts JW, Booij LH, Voerman VF, et al. The efficacy of radiofrequency lesioning of the cervical spinal dorsal root ganglion in a double blinded randomized study: No difference between 40°C and 67°C treatments. Pain 1997;73:159-63.  Back to cited text no. 17
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Son BC, Yoon JH, Kim DR, Lee SW. Dorsal rhizotomy for pain from neoplastic lumbosacral plexopathy in advanced pelvic cancer. Stereotact Funct Neurosurg 2014;92:109-16.   Back to cited text no. 20


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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