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 Table of Contents  
Year : 2019  |  Volume : 6  |  Issue : 4  |  Page : 433-438

Computed tomography-guided ganglion impar block for management of phantom rectum pain: a randomized controlled trial

1 Department of Anaesthesia, Intensive Care and Pain Management, Mansoura University, Mansoura, Egypt
2 Department of Consultant, General Surgery in Oncology Center, Mansoura University, Mansoura, Egypt
3 Department of Radiology, Faculty of Medicine, Mansoura University, Mansoura, Egypt

Date of Submission17-Jun-2019
Date of Acceptance20-Aug-2019
Date of Web Publication06-Jan-2020

Correspondence Address:
MD Nevert A Abdel Ghaffar
Department of Anaesthesia, Intensive Care and Pain Management, Faculty of Medicine, Mansoura University, 35516
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/roaic.roaic_52_19

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Background Patients who undergo abdominoperineal resection with colostomy may experience phantom rectum pain syndrome.
Aim To evaluate combined ganglion impar block and pregabaline for treatment of phantom rectum pain syndrome and improvement of quality of life.
Settings and design We conducted a randomized prospective open-label blinded end-point level IV trial in a university-affiliated oncology center in Mansoura, Egypt during the period from June 2018 to May 2019.
Patients and methods A total of 40 patients were randomly allocated into two groups: group A (n=20) received pregabaline 150 mg twice daily, and group B (n=20) received pregabaline 150 mg twice daily and ganglion impar block using 5 ml bupivacaine 5% with 14 mg/2 ml betamethasone. We monitored numerical rating scale (NRS), participant satisfaction reporting scale, pain anxiety symptoms scale, postblock complication, and success rate of block.
Statistical analysis We used χ2, t-test, and Mann–Whitney tests for statistical analysis.
Results NRS improved in each group at 1 week, 1, and 2 months in comparison with basal values (within-group P<0.001). NRS decreased in group B in comparison with group A at 1 week (P<0.001) and 1 month (P=0.01). Participant satisfaction reporting scale Q2 and Q5 were better in group B than group A (P=0.02 and 0.049; respectively). Cognition items, anxiety items, and total pain anxiety symptom scale were better in group B than group A (P=0.003, <0.001, and <0.001; respectively). No complications were detected during or after the procedure, and the success rate of the block was 95%.
Conclusion Ganglion impar block with pregabaline improved pain and quality of life in patients with phantom rectum pain syndrome.

Keywords: ganglion impar, pain, phantom, pregabaline, rectum

How to cite this article:
Abdel Ghaffar NA, Abdel Ghaffar MA, El-Badrawy A. Computed tomography-guided ganglion impar block for management of phantom rectum pain: a randomized controlled trial. Res Opin Anesth Intensive Care 2019;6:433-8

How to cite this URL:
Abdel Ghaffar NA, Abdel Ghaffar MA, El-Badrawy A. Computed tomography-guided ganglion impar block for management of phantom rectum pain: a randomized controlled trial. Res Opin Anesth Intensive Care [serial online] 2019 [cited 2020 Apr 4];6:433-8. Available from: http://www.roaic.eg.net/text.asp?2019/6/4/433/275140

  Introduction Top

Phantom pain syndrome is mostly observed after limb amputation [1]. However, it may affect any part of the body that has a sensory perception following its removal, such as breast, teeth, or rectum [2],[3].

Phantom rectum pain syndrome is rarely reported and varies from one individual to another [1],[4]. Following abdominoperineal resection with colostomy, many patients may experience this syndrome and inform of stinging and burning pain in the perineal area. Of course, this pain affects daily activities and quality of life (QOL) [5].

The pathophysiological mechanisms of phantom phenomena are still unknown, but it is neuropathic in nature and believed to be initiated by changes arising at the peripheral, spinal, and supraspinal levels, leading to central reorganization in addition to the psychogenic factor [6].

Moreover, chemotherapy and radiation induce nerve damage, leading to increased neuropathic pain occurrence [7].

A meta-analysis on guidelines of the pharmacological treatment of neuropathic pain reported that pregabaline is a first-line treatment drug [8]. Limited studies were conducted to prove its role in the management of phantom pain [9].

Ganglion impar is a sympathetic ganglion situated directly in front of the coccyx around the sacrococcygeal joint and behind the rectum in the retroperitoneal space [10],[11]. Its blockage is used to manage acute or chronic perineal pain. It could be done by local anesthetics with steroids or neurolysis by phenol, alcohol, and radiofrequency guided by fluoroscopy, computed tomography (CT), or ultrasonography [12].

Management of phantom rectum pain syndrome is a challenge. No consensus is reached for the ideal method of its treatment. From this point, we conducted our study to evaluate the effects of adding ganglion impar block to pregabaline in the treatment of phantom rectum pain syndrome. Moreover, we evaluated the effect of their combined usage on QOL.

  Patients and methods Top

Study design and participants

We conducted a randomized open-label blinded end-point pilot study in the outpatient pain clinic of a university-affiliated tertiary hospital in Mansoura, Egypt during the period from June 2018 till May 2019. The study was approved by the institutional research board (code number: R.18.09.288), was registered in the Clinical Trials (identifier: NCT03694639), and followed the guidelines of the Helsinki Declaration of 1975, as revised in 2000. Written informed consents were obtained from 40 patients aged from 18 to 70 years of both sexes who complained of phantom rectum pain syndrome after abdominoperineal surgery. The patients were diagnosed initially as having adenocarcinoma of rectum and received neo-adjuvant (preoperative) chemoradiotherapy protocol in the form of capecitabine 825 mg/m2 twice daily for 5 days till the end of radiotherapy course. The radiotherapy course delivered 45 Gy/5 weeks/25 fractions to the rectum, mesorectum, and regional lymph nodes. Then, patients were evaluated after 4 weeks by MRI pelvis and referred for surgical intervention. After abdominoperineal surgery, patients received adjuvant chemotherapy for 6 months.

Patient were excluded if refused to participate, had evidence of local infection at the puncture site, had known allergy to used drugs, had bleeding tendency or coagulopathy, had renal or hepatic failure, cardiac patients, had bony abnormalities, and had local malignant recurrence or lower vertebral metastases.

Routine investigations such as complete blood count, coagulation profile (partial thromboplastin time, prothrombin activity and international normalized ratio), and liver and renal function tests were done before the procedure. All patients were educated about the numerical rating scale (NRS) and assessed for pain intensity (if no pain=0, if it is worst pain=10).

We used fixed block randomization method for patient allocation into the corresponding groups (five blocks, each included four patients). Opaque sealed envelopes technique was used for the allocation of the participants into two groups. Group A (n=20) received pregabaline 150 mg, twice daily [13], and group B (n=20) received pregabaline 150 mg, twice daily, with ganglion impar block (5 ml bupivacaine 5% with 14 mg/2 ml betamethasone) ([Figure 1]).
Figure 1 CONSORT flow diagram of the studied patients.

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Type of analysis

Intension-to-treat analysis was used in this study.


An intravenous cannula was inserted. Vital signs and oxygen saturation were monitored throughout the procedure up to 1 h after the block. The procedure was done using 64-MDCT scanner (Brilliance 64; Philips, Healthcare, Best, The Netherlands), and parameters of CT were 200 mAs, 64×0.625 mm section collimation, 120 kVp, 1.172 pitches, 512×512 matrix, and 4-mm slice thickness.

Patients were placed in the prone position with a cushion under their lower abdomen.

CT sections were done in the axial plane to detect the site of sacrococcygeal disk. After confirming a suitable section, two distances were measured, one from patient’s spine to the proper site of entry and the other from the site of entry to the target point. Moreover, the angle of needle entrance was calculated. The skin was marked and cleaned with an aseptic solution and then anesthetized by 2-ml lidocaine 2%. A 22-G spinal needle of 12 cm was introduced until reached just anteriorly to the sacrococcygeal disk ([Figure 2]). When the needle tip location was ideal, 2-ml lidocaine mixed with 1 ml of a radiopaque dye was injected ([Figure 3]). After confirmation of contrast spread, 5-ml bupivacaine 5% with 14 mg/2 ml betamethasone was injected. CT sagittal section was done to verify the retroperitoneal distribution ([Figure 4]). We observed the patients for 1 h after block for any complications, and discharged them on the same day. We assessed QOL using participant satisfaction reporting scale (PSRS) and Pain anxiety symptoms scale (PASS). PSRS includes five items with a score ranged from 0 to 100 (0 = completely dissatisfied, 100 = completely satisfied) (Q1: How was the pain explained during the treatment?; Q2: Did you agree with the treatment?; Q3: How are you satisfied with the care?; Q4: Assess your overall improvement since the treatment initiation; and Q5: Assess your satisfaction level with your improvement since the treatment) [14]. PASS included 20 items, with a range from 0 to 5. The items of questionnaire were cognition (items 1–5), avoidance (items 6–10), fear (items 11–15), and physiological anxiety (items 16–20) [15].
Figure 2 Computed tomography axial view shows the tip of the needle in front of sacrococcygeal disk.

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Figure 3 Computed tomography axial view shows the radiopaque dye in front of sacrococcygeal disk.

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Figure 4 Computed tomography sagittal view shows the retroperitoneal distribution of the medication.

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Study outcomes

  1. Primary outcomes were NRS after 1 week, 1, and 2 months, PSRS after 2 months and PASS before and after 1 month.
  2. Secondary outcomes were postblock complication (e.g. hematoma, hypotension, and neurological defect), success rate of block (percentage of patients who had NRS<four after 1 week from block).

Statistical analysis

We used SPSS version 23 (IBM Corporation, Armonk, NY, USA). Normally distributed data were expressed as means (SD). Non-normally distributed data were expressed as median (minimum–maximum). In addition, independent t-test was used to compare the means for continuous variables of different groups. Moreover, Mann–Whitney test was used to compare non-normally distributed continuous variables in different groups. Paired t-test was used to compare matched pairs. χ2-Test was used to compare the categorical variables between both the groups. P value up to 0.05 was considered statistically significant.

  Results Top

Both groups were matched regarding age, sex, and duration after surgery, and the correlation was statistically insignificant (P=0.4, 0.7 and 0.8, respectively; [Table 1]). NRS statistically improved in each group at 1 week, 1, and 2 months in comparison with basal values (P<0.001). Moreover, between-group comparison revealed significant improvement in NRS in group B at 1 week (P<0.001) and 1 month (P=0.01). However, after 2 months, there was no significant difference (P=0.1; [Table 2]).
Table 1 Differences in participants’ characteristics and duration after surgery between both groups

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Table 2 Differences in numerical rating scale between both groups

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PSRS Q2 and Q5 were better in group B than group A (P=0.02 and 0.049, respectively), whereas Q1, Q3, Q4, and the total PSRS showed insignificant differences between both groups ([Table 3]).
Table 3 Participant satisfaction reporting scale between both groups

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Regarding PASS, cognition items, anxiety items, and total PASS improved in group B than group A after treatment (P=0.003, <0.001, and <0.001; respectively) ([Table 4]).
Table 4 Pain anxiety symptoms scale between both groups before and after one month of treatment

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There were no complications detected during or after the procedure, and the success rate of the block was 95%.

  Discussion Top

Abdominoperineal operation with permanent colostomy remains the therapeutic modality in patients with rectal cancer resistant to palliative local resection or chemoradiotherapy [16]. The incidence of phantom rectum pain is high after operation as reported by Cherng et al. [4] who found that 55% of studied patients experienced this type of pain after rectal resection operations for malignancy. Treatment of those patients is difficult and often needs multimodal therapy involving nerve blocks, pharmacologic treatment, and nonpharmacologic techniques like physical therapy, rehabilitation, acupuncture, and psychological training to get better outcomes [17].

To our knowledge, our study is the first to assess the effect of adding ganglion impar block to pregabaline for the treatment of phantom rectum pain syndrome after abdominoperineal surgery for rectal cancer. In this study, the significant decrease in pain in group B could be explained by sympathetic blockade caused by ganglion impar. This is in agreement with Agarwal-Kozlowski et al. [18], who applied CT-guided ganglion impar lateral approach with local anesthetic injection in 19 patients with perineal pain of both benign and malignant causes, and reported pain relief at the time of discharge and after 4 months. Moreover, Gunduz et al. [11] reported pain reduction for a long duration after using bupivacaine and methylprednisolone for ganglion impar block in patients with coccygodynia. Thus, the combination of local anesthetics with steroids in regional nerve blocks provides dramatic pain improvement and better compliance [17].On reviewing literature, some authors claimed that the efficacy of ganglion impar in treatment of pain is doubtful and needs further controlled trials [19].

An important observation in our study was improvement in PSRS and PASS in group B which goes hand in hand with McCracken et al. [20], who clarified that patient satisfaction has got better with pain relief and vice versa. Thus, QOL is improved, with subsequent better daily activities and performance.

Moreover, no complications were reported in the intervention group. This is explained by the advantage of CT guidance which reduces the risk of surrounding tissues and structures injury. Moreover, lateral approach provides a little risk of anal-related infection [7]. This finding confirms safety of adding ganglion block impar to pregabaline.

  Conclusion Top

Combined ganglion impar block and pregabaline could be used safely and effectively for treatment of phantom rectum pain syndrome with improvement in pain and QOL among patients with phantom rectum pain syndrome after abdominoperineal surgery.


This was a single-center study, with a short follow-up duration.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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

  [Table 1], [Table 2], [Table 3], [Table 4]


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