Distal sciatic neuropraxia secondary to lithotomy position: A case report and literature review

Abstract

Urolithiasis is one of the commonest urological diseases that can greatly impact the health status of patients with a high socioeconomic burden. Retrograde intrarenal surgery (RIRS) has been considered to be the surgery of choice for small renal stones (Less than 2 cm) due to its feasibility and safety. However, even with potentially low risk, complications can still result with RIRS. In this article we present a unique case of a 12-year-old male who had complete foot drop as a complication following RIRS. No similar case has been reported in the literature.

1. Introduction

Urolithiasis is one of the commonest urological diseases that can greatly impact the health status of patients with a high socioeconomic burden.¹ The continuous advancement in treating renal and proximal ureteric stones has been noticed in the past few decades with great evolution.¹ The goal of renal stone treatment is complete stone clearance from the genitourinary system with the least invasive approaches.¹ Retrograde intrarenal surgery (RIRS) has been considered to be the surgery of choice for small renal stones (Less than 2 cm) due to its feasibility and safety.¹ However, even with potentially low risk, complications can still result with RIRS such as hematuria, urosepsis and mortality, which are commonly mentioned in the literature.¹ In this article we present a unique case of a 12-year-old male who had complete foot drop as a complication following RIRS. No similar case has been reported in the literature.

2. Case report

A 12-year-old male not known to have any medical illness or previous surgeries presented to our clinic with a chief complaint of generalized abdominal pain for a few days. The patient denied any history of nausea, vomiting or previous similar episode of pain. Physical assessment was unremarkable. During investigations, his labs were insignificant with normal white blood cell count and negative urine culture. An X-ray was done and it showed radioopaque calculus shadow in the left kidney, so we elected to do Abdominal and pelvis CT with IV contrast. CT showed a left renal pelvis stone measuring 24*22mm with consequent mild hydronephrosis. Furthermore, 99 mTc-MAG 3 renal scan was performed and showed left non obstructive renal hydronephrosis. Surgery was offered and risks and benefits were explained to the patient and his family. The patient underwent Retrograde Intrarenal Surgery with 7.5 Fr scope and 10–12 sheath. The patient was placed in lithotomy position. Intraoperatively, the stone was visualized in the left renal pelvis, complete laser disintegration of the stone with Thulium laser was done. DJ stent was inserted. The surgery went smoothly with a duration of 90 minutes and with no intraoperative complications. Post-operative day 1, the patient was complaining of numbness and severe weakness in the right foot. Orthopedic surgery and neurosurgery were consulted. On clinical assessment, there was decreased sensation in the anterolateral aspect of the right leg and the dorsum of the right foot with weak dorsiflexion and plantar flexion of the right ankle and foot. Nerve conduction study was performed, which was unremarkable. The patient underwent thoracolumbar MRI which only showed paravertebral muscle spasm. The overall clinical assessment favored distal sciatic neuropraxia as a diagnosis likely secondary to lithotomy position. The plan was to apply foot orthosis and to start physiotherapy. In the follow-up, the patient was doing fine with mild improvement.

3. Discussion

Renal caliculus is one of the most common conditions encountered in daily practice of urology.² The estimated lifetime risk of developing renal calculi in general population reaches 13% in men and up to 7% in women.² RIRS has become more popular for treating renal and proximal ureteric calculi as it carries less risk of morbidity and mortality compared to other modalities.^1,2 With RIRS, stone recurrence rate is almost equivalent to other therapeutic modalities but with significantly lower risk of traumatizing renal tissue and causing bleeding.^1,2 Therefore, RIRS is considered to be the first line of treating renal calculi.^1,2 Nevertheless, serious complications such as severe bleeding or urosepsis can still occur.² A study conducted by Yong et al. assessed the rate of complications post RIRS and the factors that can increase the severity of these complications.³ They found that postoperative fever was the most common post-operative complication followed by mild hematuria.³ Other complications mentioned in the literature include sepsis, transit nephropathy and obstruction caused by steinstrasse.³ Distal nerve injuries secondary to lithotomy positioning are well known yet rare complications. Several contributing factors that likely increase the risk of such injuries as patient comorbidities, patient weight (more in thin patients as this patient), duration of surgery, male gender and old age.⁴ The duration of the procedure is a major influence on the likelihood of developing distal never injury.⁴ Studies support the fact that for every hour in lithotomy position the risk of nerve injury increases by 100-fold.⁴ A study conducted by Geta et al. reported 3 cases of distal nerve injuries following urological procedures in lithotomy position.⁴ All of which had distal nerve injuries following a long procedure with lithotomy time of 240, 240, 160 minutes.⁴ In contrast, in this case, the duration was much less, with a full length of 90 minutes only. Similarly, an article conducted by MAZEN et al., which reported 2 cases of peripheral nerve injuries following a brief lithotomy position.⁵ Both cases had transurethral collagen injection as a treatment of urinary incontinence with a duration of 30 minutes.⁵

However, in the literature review there were no reported cases of rare complications such as complete foot drop following RIRS. RIRS, despite its exceptional safety profile and continuous innovation and development in this field, is not without major complications, and little is known about extremely rare fatal complications. Further studies are needed in this field to identify every possible complication that could result.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Consent

Informed consent was obtained from the patient.

Declaration of competing interest

All authors have no conflicts of interest to declare.