Analgesic Modalities for Minimally Invasive Surgery

Urologic cancers consisting of prostate cancer, bladder cancer, and kidney cancer are 3 of the top 10 malignancies in the United States.¹ Annually, ~90,000 cases of prostate cancer are treated surgically, with most using minimally invasive robotic approaches.² For bladder cancer, only an estimated 1 of 5 patients will receive this curative procedure.³ Patients who receive this curative treatment are increasingly receiving treatment via minimally invasive techniques as more clinical trial data emphasize its benefits.⁴ In the realm of kidney cancer, an estimated 6000 partial nephrectomies are completed in the United States annually with a continued trend toward minimally invasive modalities.⁵

Although utilization of minimally invasive radical nephrectomy has declined with higher rates of successful partial nephrectomy, a sizable number of patients still also undergo laparoscopic or robotic partial nephrectomy.⁶ As rates of cancer diagnoses continue to increase, the quantity of minimally-invasive procedures conducted to treat these malignancies is expected to increase in volume. In this brief review, we detail the analgesic modalities available for treatment of patients undergoing minimally-invasive urologic surgery.

Types of Analgesic Modalities

Analgesic options can be broadly classified into oral nonopioid classes such as nonsteroidal anti-inflammatory drugs (NSAIDs), cyclooxygenase 2 inhibitors (COX-2), oral opioids, gabapentin, and local techniques such as transversus abdominus plane (TAP) blocks. As the now predominant modality, we will reference pain management for patients undergoing robot-assisted procedures. Most patients undergoing robot-assisted radical prostatectomy (RALP) report mild to moderate levels of pain.⁷ Similar findings can be seen with partial nephrectomy, with patients undergoing treatment with laparoscopic or robotic approaches reporting pain scores on the lower analog pain scales (average score <3).⁸

Evidence for use of NSAIDs in minimally invasive surgery comes from several trials primarily conducted in the open radical prostatectomy setting. A meta-analysis comparing prominent NSAIDs such as diclofenac and parecoxib with placebo reported that pain scores generally decreased and requirements for additional pain control also decreased.⁹

COX-2 inhibitors, a subclass of NSAIDs, are another important class of medication important in this context. COX-2 inhibitors function by inducing reversible inhibition of either COX-1 or COX-2. Aspirin, for example, is a nonselective inhibitor of both targets, whereas celecoxib, which is commonly used for pain control, specifically targets COX-2. Chelly et al conducted a study comparing celecoxib in a multimodal analgesic approach to patient-controlled morphine anesthesia.¹⁰ The authors reported a decline of slightly greater than 50% in the need for morphine in the multimodal analgesia arm.¹⁰ Similar findings were seen in a similar study comparing rofecoxib to placebo.⁹

Gabapentin for Postoperative Urologic Surgery

Gabapentin is another commonly used medication class in the postoperative setting. The exact mechanism of action for gabapentin is unknown, but it is thought to act by inhibiting calcium channels. It is commonly used in the treatment of postherpetic neuralgia, restless legs syndrome, and partial seizures.¹¹ Off-label it can be used for neuropathic pain. Deniz et al investigated the use of gabapentin in a patient population undergoing radical prostatectomy.¹²

Patients receiving a 900-mg dose of gabapentin preoperatively demonstrated a lower perception of early postoperative pain compared with patients who did not. However, total opioid pain medication consumption (tramadol in this instance) was found to be similar between the groups. This suggests that gabapentin may play a useful role in the same-day surgery setting. By reducing early postoperative pain scores, patients may feel more comfortable being discharged the same day with home pain regimens.

Opioid-Based Treatment

Opioid-based medications are generally regarded as less than ideal for primary pain management because of their class-related side effects that have been shown to delay return of bowel function and to induce bowel-related symptoms such as nausea or emesis. The recently updated expert consensus panel statement published in Journal of Urology recommends that “Patients should maximize nonopioid agents, including acetaminophen and nonsteroidal anti-inflammatory drugs, for baseline pain control unless contraindicated.”¹³ For all laparoscopic and robot-assisted procedures, the consensus statement suggests that patients maximize analgesic control with nonopioid agents such as acetaminophen and other NSAIDs.¹³ The statement recommends up to 15 doses of oxycodone 5 mg, or the equivalent, for discharge.¹³

While instillation of local anesthetic at port sites is a commonly used technique, it is worthwhile for clinicians to become familiar with some of the advanced modalities, such as continuous infusion and TAP blocks. In a placebo-controlled trial, Kristensen et al reported on the subject of local wound infusion with bupivacaine following prostatectomy.¹⁴ The goal of this technique was to improve postoperative pain control by continuous infusion of a subfascial-placed catheter for 48 hours after surgery to reduce total opioid (morphine) requirements. The authors reported that patients in the placebo arm required higher doses of morphine in the early postoperative setting; however, overall, there was no significant difference in the amount of morphine required between the 2 groups.

TAP Blocks After Urologic Surgery

TAP blocks are also commonly used after urologic surgery. Unlike some of the modalities mentioned earlier, TAP blocks have been shown in randomized trials to overall lower pain scores and lower opioid requirements. TAP blocks function by inhibition of sensory afferents along the anterior abdominal wall (T7-L1).¹⁵ Elkassabany et al conducted a randomized trial comparing patients who underwent TAP block with bupivacaine versus control (normal saline).¹⁵ Patients in the TAP arm reported overall lower pain scores and lower opioid usage over the initial 24 postoperative hours; however, they note that these effects were more prominent in the first 6 postoperative hours, suggesting that such blocks may be similarly useful for same-day discharge protocols.

Other creative modalities for pain control have also been attempted. For example, Weinberg et al reported on the use of dorsal penile nerve blocks after RALP.¹⁶ The authors randomized patients to bupivacaine dorsal penile nerve block or placebo, but the results showed no significant difference in catheter discomfort or narcotic utilization between the 2 groups.¹⁶

As larger volumes of patients are diagnosed with localized prostate, kidney, or even bladder cancer, it is crucial for clinicians to understand postoperative pain control regimens to facilitate earlier return to activities of daily life and promote earlier discharge. The studies referenced in this article focus on treatment of localized prostate cancer, but similar findings can be seen across the literature for all minimally invasive abdominal surgical procedures.

Akhil Abraham Saji, MD is a urology resident at New York Medical College / Westchester Medical Center. His interests include urology education and machine learning applications in urologic care. He is a founding and current member of the EMPIRE Urology New York AUA section team.

References

1. USCS Data Visualizations. https://gis.cdc.gov/grasp/USCS/DataViz.html. Accessed October 3, 2022.
2. Lowrance WT, Eastham JA, Savage C, et al. Contemporary open and robotic radical prostatectomy practice patterns among urologists in the United States. J Urol. 2012;187(6):2087-2092. doi: 10.1016/j.juro.2012.01.061
3. Golla V, Shan Y, Mehta HB, et al. Impact of diagnosing urologists and hospitals on the use of radical cystectomy. Eur Urol Open Sci. 2020;19:27-36. doi: 10.1016/j. euros.2020.06.001
4. Catto JWF, Khetrapal P, Ricciardi F, et al; for the iROC Study Team. Effect of robot-assisted radical cystectomy with intracorporeal urinary diversion vs open radical cystectomy on 90-day morbidity and mortality among patients with bladder cancer: a randomized clinical trial. JAMA. 2022;327(21):2092-2103. doi: 10.1001/jama.2022.7393
5. Poon SA, Silberstein JL, Chen LY, Ehdaie B, Kim PH, Russo P. Trends in partial and radical nephrectomy: an analysis of case logs from certifying urologists. J Urol. 2013;190(2):464- 469. doi: 10.1016/j.juro.2013.02.094
6. Ashrafi AN, Gill IS. Minimally invasive radical nephrectomy: a contemporary review. Transl Androl Urol. 2020;9(6):3112-3122. doi: 10.21037/tau-2019-suc-16
7. Woldu SL, Weinberg AC, Bergman A, et al. Pain and analgesic use after robot-assisted radical prostatectomy. J Endourol. 2014;28(5):544-548. doi: 10.1089/end.2013.0783
8. Shin TY, Lim SK, Komninos C, et al. Laparoendoscopic single-site (LESS) robot-assisted partial nephrectomy (RAPN) reduces postoperative wound pain without a rise in complication rates. BJU Int. 2014;114(4):555-561. doi: 10.1111/bju.12783
9. Joshi GP, Jaschinski T, Bonnet F, Kehlet H; on behalf of the PROSPECT collaboration. Optimal pain management for radical prostatectomy surgery: what is the evidence? BMC Anesthesiol. 2015;15(1):159. doi: 10.1186/s12871-015-0137-2
10. Chelly JE, Ploskanych T, Dai F, Nelson JB. Multimodal analgesic approach incorporating paravertebral blocks for open radical retropubic prostatectomy: a randomized double-blind placebo-controlled study. Can J Anesth. 2011;58(4):371-378. doi: 10.1007/s12630- 010-9442-x
11. Yasaei R, Katta S, Saadabadi A. Gabapentin. In: StatPearls. Treasure Island, FL: StatPearls Publishing; 2022. Last updated May 2, 2022. http://www.ncbi.nlm.nih.gov/books/NBK493228/. Accessed November 20, 2022.
12. Deniz M, Sertoz N, Erhan E, Ugur G. Effects of preoperative gabapentin on postoperative pain after radical retropubic prostatectomy. J Int Med Res. 2012;40(6):2362-2369. doi: 10.1177/030006051204000635
13. Koo K, Faisal F, Gupta N, et al; for the Promoting Opioid Stewardship in Endourology Work Group. Recommendations for opioid prescribing after endourological and minimally invasive urological surgery: an expert panel consensus. J Urol. 2020;203(1):151-158. doi: 10.1097/JU.0000000000000514
14. Kristensen BS, Fenger-Eriksen C, Pedersen KV, Felsby S. Wound infusion of bupivacaine following radical retropubic prostatectomy: a randomised placebo-controlled clinical study. Eur J Anaesthesiol. 2013;30(3):124-128. doi: 10.1097/EJA.0b013e32835c6f25
15. Elkassabany N, Ahmed M, Malkowicz SB, Heitjan DF, Isserman JA, Ochroch EA. Comparison between the analgesic efficacy of transversus abdominis plane (TAP) block and placebo in open retropubic radical prostatectomy: a prospective, randomized, double-blinded study. J Clin Anesth. 2013;25(6):459-465. doi: 10.1016/j. jclinane.2013.04.009
16. Weinberg AC, Woldu SL, Bergman A, et al. Dorsal penile nerve block for robot-assisted radical prostatectomy catheter related pain: a randomized, double-blind, placebocontrolled trial. Springerplus. 2014;3(1):181. doi: 10.1186/2193-1801-3-1