Ultrasound-Guided Ganglion Impar Block: A Technical Report

Image-guided peripheral nerve interventions- applications and techniques

Interventional radiology continues to be at the forefront of acute and chronic pain management. Our unique imaging expertise and ability to target difficult to reach structures allows for the continuous development of new ways to treat a variety of pain generators. In addition, the advent of thermal ablation techniques and technologies has provided a unique opportunity to offer patients more durable and predictable options to treat their pain. This is particularly important during the opioid epidemic, as multiple local and international governmental bodies push for physicians to create ways to manage pain while reducing the need for long-term opioid dependence. This article aims to review various image-guided techniques and tools for the treatment of pain related to peripheral pain generators, with a focus on the extremities, lumbosacral and pelvic region, and the chest wall. For each target and pathology, we will discuss general etiology, anatomy, procedural approach, and briefly evaluate the supporting literature in each clinical situation.

Regional anesthesia for pain control in children with solid tumors-a review of case reports

Introduction

Around seventy percent of all childhood cancer patients suffer from severe pain. This pain can arise from various sources, including tumors themselves, pain caused by metastasizing tumor cells or as the outcome of therapy meant to deal with tumors. If managed inadequately, such pain can lead to many hazardous sequelae. However, there are extreme cases when pain does not respond to standard treatment. For such cases, regional anesthesia or nerve blocks are utilized as the utmost pain control measure. Blocks are used to treat pain in patients who no longer respond to conventional opioid-based treatment or whose worsened condition makes it impossible to receive any other therapy. The data regarding the use of regional anesthesia for such cases in the children population is limited.

Methods

For this review we searched for case reports in Scopus and PubMed from inception to 2023. The descriptive search items included terms related to childhood cancer and the description of each block. The inclusion criteria for review include children (0-18 years old) receiving oncology-related surgical procedures or palliative care. The data collection was limited to solid tumor-related cases only. We analyzed a total of 38 studies that included case reports and one retrospective study.

Results and discussion

It was concluded that nerve blocks, although rarely performed, are a safe and efficient way of pain control in children with solid tumors. The major settings for block performance are postoperative pain control and palliative care. We observed that block indication and its outcomes depend on unique health circumstances in which they should be performed. Patients with similar diagnoses had differing outcomes while receiving the same block treatment.

Interventional Treatment Modalities for Chronic Abdominal and Pelvic Visceral Pain

PURPOSE OF REVIEW

Chronic abdominal and pelvic visceral pain is an oftentimes difficult to treat pain condition that requires a multidisciplinary approach. This article specifically reviews the interventional treatment options for pain resulting from visceral abdominal and pelvic pain.

RECENT FINDINGS

Sympathetic nerve blocks are the main interventional option for the treatment of chronic abdominal and pelvic visceral pain. Initially, nerve blocks are performed, and subsequently, neurolytic injections (alcohol or phenol) are longer term options. This review describes different techniques for sympathetic blockade. Neuromodulation is a potential option via dorsal column stimulation or dorsal root ganglion stimulation. Finally, intrathecal drug delivery is sometimes appropriate for refractory cases. This paper will review interventional options for the treatment of chronic abdominal and pelvic visceral pain.

The American Society of Pain and Neuroscience (ASPN) Best Practices and Guidelines for the Interventional Management of Cancer-Associated Pain

Moderate to severe pain occurs in many cancer patients during their clinical course and may stem from the primary pathology, metastasis, or as treatment side effects. Uncontrolled pain using conservative medical therapy can often lead to patient distress, loss of productivity, shorter life expectancy, longer hospital stays, and increase in healthcare utilization. Various publications shed light on strategies for conservative medical management for cancer pain and a few international publications have reviewed limited interventional data. Our multi-institutional working group was assembled to review and highlight the body of evidence that exists for opioid utilization for cancer pain, adjunct medication such as ketamine and methadone and interventional therapies. We discuss neurolysis via injections, neuromodulation including targeted drug delivery and spinal cord stimulation, vertebral tumor ablation and augmentation, radiotherapy and surgical techniques. In the United States, there is a significant variance in the interventional treatment of cancer pain based on fellowship training. As a first of its kind, this best practices and interventional guideline will offer evidenced-based recommendations for reducing pain and suffering associated with malignancy.

Imaging Coccygeal Trauma and Coccydynia

The coccygeal region has complex anatomy, much of which may contribute to or be the cause of coccyx region pain (coccydynia). This anatomy is well depicted at imaging, and management is often dictated by what structures are involved. Coccydynia is a common condition that is known to be difficult to evaluate and treat. However, imaging can aid in determining potential causes of pain to help guide management. Commonly, coccydynia (coccygodynia) occurs after trauma and appears with normal imaging features at static neutral radiography, but dynamic imaging with standing and seated lateral radiography may reveal pathologic coccygeal motion that is predictive of pain. In addition, several findings seen at cross-sectional imaging in patients with coccydynia can point to a source of pain that may be subtle and easily overlooked. Radiology can also offer a role in management of coccygeal region pain with image-guided pain management procedures such as ganglion impar block. In addition to mechanical coccyx pain, a host of other conditions involving the sacrococcygeal region may cause coccydynia, which are well depicted at imaging. These include neoplasm, infection, crystal deposition, and cystic formations such as pilonidal cyst. The authors review a variety of coccydynia causes, their respective imaging features, and common management strategies.^©RSNA, 2020.

Comparative evaluation of transsacrococcygeal and transcoccygeal approach of ganglion impar block for management of coccygodynia

BACKGROUND AND AIMS

Coccygodynia or Coccydynia is pain in the area of coccyx and ganglion impar block is commonly used technique for treatment of coccygodynia.

MATERIAL AND METHODS

Forty patients of either sex in the age group of 20-70 years suffering from coccygodynia, who failed to respond to six weeks of conservative treatment were enrolled in the study. All patients were subjected to detailed clinical history, examination in the Pain Management Centre (Pain Clinic) of our Institute and imaging studies were reviewed. The patients were randomly divided into two groups of 20 each by a computer generated randomization number table: Group-TS (n = 20): Patients were administered ganglion Impar block by trans-sacrococcygeal approach Group-TC (n = 20): Patients were administered ganglion Impar block by trans-coccygeal approach with 8 ml of 0.5% bupivacaine plus 2 ml of 40mg/ml methylprednisolone acetate under fluoroscopic guidance.

RESULTS

Both the techniques of ganglion Impar block were effective and provided good pain relief to the patients with coccygodynia. There was a statistically and clinically significant improvement in pain score after ganglion Impar block in both the groups at all time intervals during the study period. (p < 0.05). The mean pain score after ganglion Impar block was <2 at all time intervals throughout the three month study period in all patients in the two groups. All patients in both the groups had excellent satisfaction immediately after ganglion Impar block. Five patients each in both groups required second ganglion Impar block during the three months study period.

CONCLUSION

Both trans-sacrococcygeal and trans-coccygeal approaches of ganglion Impar block with a combination of local anaesthetic and steroid are safe and effective for management of coccygodynia. Trans-coccygeal ganglion Impar block through the first intra-coccygeal joint is better in terms of improvement in pain score, functional disability, patient satisfaction and ease of administration.

Risk of rectal puncture due to needle entry into the presacral space: Importance of measuring the distance between the rectum and sacrococcyx, and the thickness of the sacrococcyx

During ganglion impar block, the needle may approach the presacral space and the sacrum may be penetrated during caudal anesthesia. Because the rectum is in front of the sacrococcyx and is thus at risk for puncture, it is important to determine the distance between the sacrococcyx and rectum, as well as the thickness of the sacrococcyx.Computed tomography was used to measure the distance between the rectum and sacrococcyx, as well as the thickness of the sacrococcyx. The distances between the coccyx and rectum, sacrococcygeal joint and rectum, sacral level 5 ('sacrum 5') and rectum, and 'sacrum 4 to 5 junction' and rectum were measured. The results were compared based on the presence or absence of stools in the rectum. The thickness of the sacrococcyx was measured at the sacrum 4 to 5 junction and sacrococcygeal joint.In total, 1264 patients were included in this study. All distances were less than 1 mm in both males and females, with the exception of the distance between the coccyx and rectum in males. In both males and females, there was no significant difference in distance between the sacrococcyx and rectum according to the presence or absence of feces in the rectum, but there was a difference in the distance between sacrum 5 and the rectum in males (P = .048). Several male and female patients showed thicknesses of less than 5 mm at the sacrococcygeal joint.Some patients have a distance of less than 1 mm between the sacrum and rectum. Practitioners should exercise caution when applying a needle to the presacral space. If the sacrum is accidentally penetrated during caudal block, rectum puncture cannot be ruled out. Excretion of feces does not influence the distance between the sacrococcyx and rectum in females.

Retrospective evaluation of pain in patients with coccydynia who underwent impar ganglion block

Background

We aimed to evaluate pain scores one year after impar ganglion block in patients with coccydynia who did not benefit from conservative treatment.

Methods

The medical records of 29 patients with coccydynia were reviewed. Patients who were referred to the algology clinic and underwent impar ganglion blocks were retrospectively evaluated. Demographic data, time to the onset of pain, causes of pain, X-ray findings, administered invasive procedures, and visual analog scale (pain) scores were recorded.

Results

A total of 29 patients were included in the study, 10 males (34%) and 19 females (66%). The average age and body mass index were 53.45 ± 9.6 and 29.55 ± 4.21 respectively. In 21 patients, the onset of pain was associated with trauma. Nineteen patients (65.5%) had anterior coccygeal angulation. The average visual analog scale score before undergoing an impar ganglion block was 7.4 ± 1. After the procedure, the scores at < 3 months, 3–6 months and 6 months-1 year follow-up intervals were significantly lower (p < 0.05). Furthermore, visual analog scale scores at the 3–6 months and 6 months-1 year periods were significantly lower in patients who received diagnostic blocks plus pulse radiofrequency thermocoagulation than in patients who underwent a diagnostic block only.

Conclusions

The impar ganglion block provides effective analgesia without complications in patients with coccydynia. Pulse radiofrequency thermocoagulation combined with a diagnostic block prolongs the analgesic effect of the procedure.

Conus infarction after non-guided transcoccygeal ganglion impar block using particulate steroid for chronic coccydynia

Introduction

Ganglion impar block (GIB) is a well-recognised treatment for chronic coccydynia. Several side effects have previously been described with this procedure, including transient motor dysfunction, bowel, bladder, and sexual dysfunction, neuritis, rectal perforation, impingement of the sciatic nerve, cauda equina syndrome, and infection.

Case presentation

We describe the first report of imaging-documented conus infarction after an unguided-GIB performed in theatre using particulate steroids for a 17-year-old patient with coccydynia. Immediately post-GIB, patient developed transient neurological deficits in her lower limbs of inability to mobilise her legs that lasted for 24 h. These include back and leg pain, decreased power and movement, increased tone, brisk reflexes, reduced light touch sensation and proprioception of legs up to the T10 level. Urgent MRI spine showed intramedullary hyperintense signal within the conus and mild restricted diffusion on the distal cord and conus, suggestive of an acute conus infarction. On follow-up, the GIB did not result in symptom improvement of coccydynia and there was persistent altered sensation of her legs.

Discussion

Various approaches of ganglion impar block have been described and performed in the past with different imaging techniques and injectants. A few cases of unusual neurological complications have been reported with the use of epidural steroid injections and ganglion impar block. Clinicians should be aware of the possible neurological complications following ganglion impar blocks and the risk of inadvertent intravascular injection of particulate steroids can potentially to be minimised by using imaging guidance.

A prospective study to evaluate the efficacy of ultrasound-guided ganglion impar block in patients with chronic perineal pain

BACKGROUND

The blockade of the ganglion impar has been described to relieve the intractable perineal pain of sympathetic origin in patients with coccydynia. Chronic perineal pain (CPP) has been effectively managed by ganglion impar block. The feasibility, safety, and efficacy of ultrasound (US)-guided ganglion impar block by transsacrococcygeal approach was analyzed in the present study.

METHODS

A total of 15 patients with CPP were administered US-guided ganglion impar block using out of plane approach. Patients were followed for VAS and quality of life using Karnofsky performance status (KS), Linear Analog Scale Assessment (LASA), and constipation score up to 2 months at different time intervals. Time required to perform the procedure, number of attempts, and any complications were also noted.

RESULTS

The mean time required to perform the procedure was 7.67 ± 1.23 min. There were no adverse events. All the patients had significant pain relief during 2 month follow-up (P < 0.05 compared to baseline VAS). The KS and LASA score improved post block which was statistically significant. The dose of nonsteroidal anti-inflammatory drugs (NSAIDS) decreased from preblock state with statistically significant difference, while the difference in dose of tramadol and morphine was statistically insignificant.

CONCLUSION

US-guided ganglion impar block is technically feasible and safe technique. USG can be used to locate sacrococcygeal junction (SCJ) and facilitate the performance of ganglion impar block. The efficacy and safety of the US-guided ganglion impar blockades needs a proper evaluation in the randomized controlled trials.

An overview of interventional strategies for the management of oncologic pain

Pain is a ubiquitous part of the cancer experience. Often the presenting symptom of malignancy, pain becomes more prevalent in advanced or metastatic disease and often persists despite curative treatment. Although management of cancer pain improved following publication of the WHO's analgesic ladder, when used in isolation, conservative approaches often fail to control pain and are limited by intolerable side effects. Interventional strategies provide an option for managing cancer pain that remains refractory to pharmacologic therapy. The purpose of this review is to investigate these strategies and discuss the risks and benefits which must be weighed when considering their use. Therapies anticipated to have an increasingly important role in the future of cancer pain management are also discussed.

Transcoccygeal neurolytic ganglion impar block for perineal pain: A case series

BACKGROUND AND AIMS

Chronic perineal pain (CPP) is a poorly localized pain. Its etiology may be benign or malignant. The ganglion impar is a solitary retroperitoneal structure at sacrococcygeal junction. It provides the nociceptive and sympathetic supply to the perineal structures. CPP has been effectively managed by ganglion impar block. Here, we describe a case series of neurolytic ganglion impar block by transcoccygeal approach, analyzing its safety and efficacy.

MATERIAL AND METHODS

In this study, five consecutive patients who were given ganglion impar block for CPP using a transcoccygeal approach were followed up for 2 months. The visual analog scale (VAS) score for pain at presentation, time required for the pain to reduce by 50% after the block, VAS during a 2-month follow-up, time required to perform the procedure, number of attempts, and any complications were noted.

RESULTS

All the five patients had an excellent pain relief. The mean duration for decrease in VAS by 50% was 14.8 ± 3.1 min. The mean duration to perform the procedure was 10.2 ± 1.5 min. There were no complications. All the patients had clinically significant pain relief with VAS score of 2 till 2-month follow-up.

CONCLUSION

Transcoccygeal ganglion impar block may offer a safe and effective treatment option for CPP as compared to opioids. This approach for neurolysis of the ganglion impar may be recommended in view of the direct course, appreciable end point, and smaller volume of neurolytic requirement.

Ganglion blocks as a treatment of pain: current perspectives

The inputs from sympathetic ganglia have been known to be involved in the pathophysiology of various painful conditions such as complex regional pain syndrome, cancer pain of different origin, and coccygodynia. Sympathetic ganglia blocks are used to relieve patients who suffer from these conditions for over a century. Many numbers of local anesthetics such as bupivacaine or neurolytic agents such as alcohol can be chosen for a successful block. The agent is selected according to its duration of effect and the purpose of the injection. Most commonly used sympathetic blocks are stellate ganglion block, lumbar sympathetic block, celiac plexus block, superior hypogastric block, and ganglion Impar block. In this review, indications, methods, effectiveness, and complications of these blocks are discussed based on the data from the current literature.

MR-guided perineural injection of the ganglion impar: technical considerations and feasibility

OBJECTIVE

Perineural ganglion impar injections are used in the management of pelvic pain syndromes; however, there is no consensus regarding the optimal image guidance. Magnetic resonance imaging (MRI) provides high soft tissue contrast and the potential to directly visualize and target the ganglion. The purpose of this study was to assess the feasibility of MR-guided percutaneous perineural ganglion impar injections.

MATERIALS AND METHODS

Six MR-guided ganglion impar injections were performed in six human cadavers. Procedures were performed with a clinical 1.5-Tesla MRI system through a far lateral transgluteus approach. Ganglion impar visibility, distance from the sacrococcygeal joint, number of intermittent MRI control steps required to place the needle, target error between the intended and final needle tip location, inadvertent punctures of non-targeted vulnerable structures, injectant distribution, and procedure time were determined.

RESULTS

The ganglion impar was seen on MRI in 4/6 (66 %) of cases and located 0.8 mm cephalad to 16.3 mm caudad (average 1.2 mm caudad) to the midpoint of the sacrococcygeal joint. Needle placement required an average of three MRI control steps (range, 2-6). The average target error was 2.2 ± 2.1 mm. In 6/6 cases (100 %), there was appropriate periganglionic distribution and filling of the presacrococcygeal space. No punctures of non-targeted structures occurred. The median procedure time was 20 min (range, 12-29 min).

CONCLUSION

Interventional MRI can visualize and directly target the ganglion impar for accurate needle placement and successful periganglionic injection with the additional benefit of no ionizing radiation exposure to patient and staff. Our results support clinical evaluation.

Ultrasound-guided interventional procedures for chronic pain management

Ultrasonography has multiple advantages over traditional radiologic imaging modalities when used for interventional procedures. It allows improved visualization of the anatomy while avoiding ionizing radiation and risks associated with contrast use. It has proved superiority at accuracy of delivery and procedural effectiveness over blind procedures when used in association with interventional pain procedures. Although limited in its ability to see through bony structures, ultrasound has utility in visualizing soft tissues and vascular structures in anatomic regions of interest resulting in increased use for posterior neuraxial, periaxial, peripheral nerve and joint-related structures. Current evidence for use in these settings is presented here. In some cases, optimal utility may be improved by combining ultrasonography with other imaging modalities.

[Ultrasound-guided facet block to low back pain: a case report]

BACKGROUND

Osteoarthrosis is a common cause of low back pain. The diagnosis is clinical and can be confirmed by imaging studies. Pain treatment and confirmation of diagnosis are made by intra-articular injection of corticosteroid and by local anesthetic use, due to clinical improvement. A direct monitoring of the procedure can be done under fluoroscopy, a classic technique, or else by an ultrasound-guided procedure.

CASE REPORT

Female patient, 88 years old, 1.68m and 72kg, with facet osteoarthrosis at L2-L3, L3-L4 and L4-L5 for two years. On physical examination, she exhibited pain on lateralization and spinal extension. We opted in favor of an ultrasound-guided facet joint block. A midline spinal longitudinal scan was obtained, with identification of the desired joint space at L3-L4. A 25 G needle was inserted into the skin by the echographic off-plane ultrasound technique. 1 mL of contrast was administered, with confirmation by fluoroscopy. After aspiration of the contrast, 1 mL of solution containing 0.25% bupivacaine hydrochloride and 10 mg of methylprednisolone acetate was injected. Injections into L3-L4, L2-L3 and L1-L2 to the right were applied.

CONCLUSIONS

The visualization of the facet joint by ultrasound involves minimal risk, besides reduction of radiation. This option is suitable for a large part of the population. However, fluoroscopy and computed tomography remain as monitoring techniques indicated for patients with specific characteristics, such as obesity, severe degenerative diseases and anatomical malformations, in which the ultrasound technique is still in need of further study.

One is the loneliest number: a review of the ganglion impar and its relation to pelvic pain syndromes

The ganglion impar is often overlooked as a component of the sympathetic nervous system. Despite its obscurity, this ganglion provides a pathway for neurons by accommodating postganglionic sympathetics, visceral afferents, and somatic fibers traveling to and from the pelvis. Its classic anatomic location as described in the 1720's held up until recently, with the current literature now revealing a great deal of anatomical variability. This variation becomes important when the ganglion impar is used as a treatment target for patients with chronic pelvic pain - its primary clinical implication. The aim of this review was to provide a better understanding of the anatomy of ganglion impar, accounting for variation in size, shape, and location. In addition, the clinical importance and treatment modalities associated with the ganglion impar are outlined.

Blockade of the ganglion impar (walther), using ultrasound and a loss of resistance technique

The ganglion impar is an unpaired sympathetic structure located at the level of the sacrococcygeal joint. Blockade of this structure has been utilised to treat chronic perineal pain. Methods to achieve this block often involve the use of fluoroscopy which is associated with radiation exposure of staff involved in providing these procedures. We report a combined loss of resistance injection technique in association with ultrasound guidance to achieve the block. Ultrasound was used to identify the sacrococcygeal joint and a needle was shown to enter this region. Loss of resistance was then used to demonstrate that the needle tip lies in a presacral space. The implication being that any injectate would be located in an adequate position. The potential exception would be a neurodestructive procedure as radiographic control of needle tip in relation to the rectum should be performed and recorded. However when aiming for a diagnostic or local anaesthetic based treatment option we feel that this may become an accepted method.