CT guided neurolytic blockade of the coeliac plexus in patients with advanced and intractably painful pancreatic cancer

1 Introduction

Pain caused by cancer infiltration of abdominal structures is complex in nature and the mechanisms are characterized by a mixture of somatic, visceral and neuropathic components [1], [2]. The sympathetic nervous system has an important role in regulating visceral function, and with its anatomical distribution retroperitoneally including the coeliac plexus, it is often affected by retroperitoneal spread of abdominal cancer, causing severe pain [3], [4], [5]. Because of its complexity, such abdominal pain is known to be difficult to handle with drugs, without causing severe side effects. This is typically seen with pancreatic cancer, which may infiltrate the nerves of the coeliac plexus, thus causing a mixture of visceral and neuropathic pain [6]. Performing a neurolytic blockade of the coeliac plexus either as an open perioperative procedure, or via a non-operative percutaneous technique, may induce a substantial reduction of pain with a limited risk of side effects [7], [8], [9]. This procedure may thus improve quality of life by reducing the need for conventional analgesics and their burden of side effect. For some patients a plexus blockade relieves pain almost immediately, and for most patients it is either a better alternative to or a good addition to conventional pain treatment [5], [10].

Traditionally a coeliac blockade has been performed by an experienced anaesthesiologist with the help of X-ray fluoroscopy using a dorsal approach [11], [12]. Fluoroscopy only gives a limited view of the area, seeing only the bony details. Neither is it possible to identify the needles position towards the different organs in the area. This is remedied by using Computer Tomograph (CT) for placing the needle. By performing a CT guided procedure the radiologist can place the needle in an exact spot, and by controlling with a new set of CT images, one may also see exactly how the contrast media spreads [13]. The anaesthesiologist may then have full control when injecting.

The present study is a retrospective study done in order to evaluate the quality of CT-guided coeliac blockades, both technically, the immediate outcome and with clinical follow-up of the palliative treatment.

2 Patients and methods

Eleven procedures in 10 patients (two procedures in one patient) were performed. All patients, five women and five men, had advanced pancreatic cancer. The patients were aged 49–75 years, mean 59 and median 56 years. All patients were referred to a palliative clinic due to intractable pain, and received high doses of opioids. To be able to compare opioid dose, the total daily opioid consumption was calculated and expressed as daily oral morphine dose, based on EAPC guidelines for opioid equianalgesic dose ratios [14]. Basic demographic data and opioid treatment prior to the blockade is presented in Table 1.

The patient was placed prone on pillows, awake, monitored by NIBP, ECG and pulse oximetry. I.v. line was established with Ringer acetate, Fresenius Kabi, and sedatives/analgesics given if needed. A sterile setting was prepared, in accordance with standard hygienic principles for washing, clothing and covering.

All procedures were performed on a CT, GE VCT™, Milwaukee, WI, USA. An abdominal CT series of the upper abdomen were first performed to find the best area for the procedure. Left side was preferred if possible to avoid the caval vein. When a suitable line for the invasive procedure was found, the line was marked before washing and covering, and the skin area infiltrated with local anesthesia, Xylocain™, AstraZeneca, 10 mg/mL 8–10 mL. Extra local anesthesia was applied if pain occurred during needle placement. The needle tip was advanced into proper position guided by the CT’s “Biopsy RX” mode, which means five slices per scan (Fig. 1). We used 5 mm slices (one centred, two above and two below the expected slice).

Fig. 1:

Axial CT scan on a 75 years old female patient showing needle tip adjacent to the 2 lumbar vertebra, directing between the aorta and the caval vein to reach the coeliac plexus from right side.

When the needle tip was in an anticipated perfect position, laterally to the anterior edge of the aorta, 5 mL contrast medium, Omnipaque™, GE Healthcare, was injected in order to control the position (Fig. 2). If the contrast medium flowed freely around the aorta, the position was considered perfect. If not, the needle was adjusted. If, after adjustment, the contrast did not flow freely, a new needle was inserted on the contralateral side, following the same procedure (Fig. 3). After seeing that contrast media had covered the space anterior to and to both sides of the aorta, a CT series of the actual area was performed. This in order to see that contrast had filled the space.

Fig. 2:

Axial CT scan on a 75 years old male patient showing needle in final position and contrast spreading in the tissue surrounding the left side of the aorta.

Fig. 3:

Axial CT scan on the same patient as in Fig. 2 showing contrast from the first needle and a second needle in position on the right side with contrast spreading from the tip.

When location of needle tip(s) were considered perfect, a last dose of local anesthesia was applied, thereafter the neurolytic drugs could be injected.

The neurolytic blockade was performed by the anaesthesiologist after the following procedure:

Forty milligram methylprednisolone was injected first to prevent inflammation. Thereafter a mixture of 99% ethanol diluted to approximately 50% by ropivacaine 7.5 mg/mL to a total amount of 20–30 mL/needle was slowly injected. The injection was stopped temporarily if the patient reported pain, and restarted as soon as the pain was gone. Aspiration to detect blood was done repeatedly during injection. If blood appeared in the needle, it was rinsed with saline, and aspirated. If there was still blood coming, more contrast was given followed by a new scan to exclude vessel perforation. If so, the needle was repositioned.

After completion of the planned neurolytic volume, the spread was controlled by 2–3 mL of contrast, followed by a broader CT-scan, before the needle was withdrawn. The patient was observed in a recovery area for at least 2 h before discharge. Thereafter the patient was transported to the palliative ward and observed for at least 24 h concerning the risk of orthostatic hypotension and frequent bowel emptying.

3 Results

All the 11 procedures were technically/radiologically successful. The needles were placed in a proper position in all patients and no complications were recorded adjacent to the procedure, especially no large vessel perforations. All patients reported an immediate and remarkable pain reduction, and several of them fell asleep after completing the procedure. No significant changes needing special treatment concerning blood pressure, pulse frequency, oxygen saturation or consciousness was recorded. No patients needed extra observation. A new pain management regime was made for each patient according to the effect of the blockade. For most patients a significant reduction in both pain intensity and medical need was observed the day after the blockade. However, the duration of effect varied a lot, for some patients the effect was only temporary, but about 50% of the patients had a significant and long-lasting effect with reduced consumption of opioids along with a lower pain score. Two of the patients experienced no effect on either pain score or analgesic consumption. Rest lifetime after the blockade was very short for most patients, with a median time to death of 36 days. However, we were not able to perform a close follow up after discharge from hospital, as they came from very different locations.

The differences in medication before and after the blockade is presented in Table 2. The clinical evaluation of possible improvement in pain/clinical status is presented in Table 3.

4 Discussion

Neurolytic blockade of the coeliac plexus to treat pain due to pancreatic cancer has been practiced for more than 40 years [5], [7], [12], [15]. Even though several studies have described positive effect on pain and patient outcome, the scientific evidence has been questioned because of lack of high quality studies [8]. A Cochrane review in 2011 concluded that the statistical evidence is minimal for the superiority of pain relief compared to conventional analgesic treatment, but the side effects are fewer [16]. More high quality research is desirable, but it is difficult to fulfil standards for a scientific high quality study in these very sick patients. This because such a study design may be in discordance with ethical considerations concerning proper care, and compromises therefore has to be accepted.

A systematic review from 2015 concludes that the overall effect on pain seems strong, but data on which technique to choose is lacking [4]. Traditionally, in nonoperated patients blockade was guided by X-ray fluoroscopy, but has during the last two decades been replaced by the use of CT scan or Endoscopic Ultrasound guidance (EUS) [17]. So far there has not been published any studies to compare these newer approaches, which call upon different techniques and skills. The EUS technique is performed by specially trained gastroenterologists, while the CT guided technique is performed by a senior radiologist in cooperation with a senior anaesthesiologist [18]. Which technique to recommend depend on the local expertise, but in our opinion the CT guided technique is more easy to teach and perform, and is definitely more precise than using fluoroscopy. The side effects using CT guidance are few and controllable, and the procedures may be repeated with limited risk [11], [13]. Even though, as in our study, it is not possible to achieve pain relief in all patients. This fact may have several explanations. Large tumor masses around pancreas may displace normal structures, and thereby interfere with and modify the spread of neurolytic agents in the perivascular area surrounding the coeliac plexus. Using a larger volume of neurolytic agent and always doing bilateral blocks could overcome this problem, but a higher total load of ethanol would also increase side effects in these very sick patients. It is also possible to repeat the blockade to increase the success rate. It is important to underline that the blockade only affects sympathetic pain mechanisms, and these patients’ pain is usually a mixture of somatic pain, neuropathic pain and sympathetic pain, where one mechanism may dominate the others [19]. Especially when the cancer disease become advanced with peritoneal, lymph node and/or liver spread, the pain mechanisms also grow in complexity with a pronounced somatic component, leaving it more difficult to achieve effect of a sympathetic blockade. In accordance with what is described in the literature, our experience is that the least effect is seen in the most advanced cases. All our patients were referred from the department of oncology because of increasing pain and suffered from advanced disease, and their median rest lifetime after the blockade was only 36 days.

Our study is small, and of course has its limitations; therefore we have to be cautious with our conclusions. It has to be noted that the success rate might have been higher if we had used larger doses of ethanol to perform the neurolysis, and repeated the blockade in patients with limited effect.

As high quality large scale studies still are lacking, we have to rely on data from smaller studies in the best interest of our patients. In our opinion it is also important to share experience on how to perform coeliac plexus blockade in a safe way.

In palliative medicine the main interest is to relieve symptoms without doing more harm or binding the patient to the hospital. Even though a coeliac blockade may come out without a significant effect, the harm is limited, and the patient may leave the hospital the next day without any serious risks.

Our conclusion is therefore quite firm: Neurolytic coeliac blockade is a good addition to medical palliation and should be part of the standard armamentarium offered to this group of patients.