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 Table of Contents  
Year : 2020  |  Volume : 4  |  Issue : 2  |  Page : 118-122

Comparison between ultrasound-guided sciatic–femoral nerve block and unilateral spinal anesthesia in below-knee amputation surgery

1 Department of Anesthesiology and Intensive Care, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
2 Department of Surgery, Faculty of Medicine, Al Azhar University, Cairo, Egypt

Date of Submission20-Jan-2020
Date of Decision07-Feb-2020
Date of Acceptance09-Feb-2020
Date of Web Publication29-Jun-2020

Correspondence Address:
MD Ayman Esmail Hussien
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sjamf.sjamf_6_20

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Objectives To compare unilateral spinal anesthesia and ultrasound-guided combined sciatic–femoral nerve block (SFB) regarding hemodynamic stability, quality of nerve block, bladder function, and time-to-readiness for discharge (TRD) in below-knee amputation surgery.
Patients and methods A total of 80 patients who underwent knee amputation surgery (40 per group) were enrolled in the study. They were randomly assigned to one of two groups. Group A received 2 ml (10 mg) of 0.5% levobupivacaine, and group B (SFB) received 25 ml contains 10 ml of 2.0% lidocaine, 10 ml of 0.5% levobupivacaine, and 5 ml of saline (15 ml of femoral and 10 ml of sciatic nerve block). Surgical anesthesia time, time of operation, total time of anesthesia, time-to-first spontaneous urination, time-to-first analgesia, TRD, and patient satisfaction were recorded.
Results Onset of sensory and motor blocks was significantly shorter in group A compared with group B, whereas the recovery time for sensory and motor blocks was longer in group B compared with group A. In the group A, time-to-first analgesia was significantly shorter than the SFB group B; time-to-first spontaneous urination and TRD in the group A were significantly longer than the SFB group B. Pain score was highly significant lower in group B compared with group A after surgery.
Conclusion SFB provided sufficient sensory blockage, duration, patient satisfaction, and postoperative analgesia than the unilateral spinal anesthesia.

Keywords: below-knee amputation, pain, postoperative outcomes, sciatic–femoral nerve block, spinal anesthesia, ultrasound-guided

How to cite this article:
Hussien AE, Abd Elhalim ME, Zarad MS. Comparison between ultrasound-guided sciatic–femoral nerve block and unilateral spinal anesthesia in below-knee amputation surgery. Sci J Al-Azhar Med Fac Girls 2020;4:118-22

How to cite this URL:
Hussien AE, Abd Elhalim ME, Zarad MS. Comparison between ultrasound-guided sciatic–femoral nerve block and unilateral spinal anesthesia in below-knee amputation surgery. Sci J Al-Azhar Med Fac Girls [serial online] 2020 [cited 2020 Oct 22];4:118-22. Available from: http://www.sjamf.eg.net/text.asp?2020/4/2/118/288288

  Introduction Top

Patients with nontraumatic lower extremity amputation, such as knee amputation, usually have multiple comorbidities such as diabetes mellitus and cardiovascular and renal dysfunctions [1],[2]. In prior studies, the operations were successfully performed under ultrasound-guided combination of femoral and sciatic nerve blocks [1],[2].

They are at high risk of surgical morbidity and mortality. It is intended for prompt protection of infectious origin when performed as an emergency in an excessive soft tissue or bone disease. At this stage of presentation, patients are in severe sepsis with multiorgan dysfunction associated with poor comorbidity, leading to high risk of perioperative complications.

In one study, an individual with American Society of Anesthesia level 4 in nontraumatic lower extremity amputation was associated with a more than four-fold increase in 30-day mortality and a double increase in long-term mortality [2]. Long-term survival is dismal for those with knee amputation [3].

Regional approaches to intraoperative anesthesia and postoperative analgesia were used whenever possible. Therefore, local anesthetics are the most widely used drugs, but they are short lived and can lead to undesirable effects such as motor block and hypotension [3]. Regional anesthesia techniques are used as an alternative to general anesthesia in the below-knee amputation procedures [4],[5]. It is generally accepted that peripheral nerve blocks and spinal anesthesia offer sufficient anesthesia and postoperative analgesia and satisfaction compared with general anesthesia [5],[6].

In particular, unilateral spinal anesthesia is recommended for patients undergoing unilateral lower limb surgery as only the target area is subject to nerve blockage, resulting in early recovery and high patient satisfaction [5],[7],[8].

In lower limb surgery, the combined sciatic–femoral nerve block (SFB) is also used unilaterally, but it is less widely used because it takes longer to perform, involving a higher dose of local anesthetic.

Ultrasound-guided SFB is the ideal technique as it avoids SFB-related adverse effects such as blockage and damage to nerves and structures such as artery and vein and associated, with a number of benefits such as less needle insertion, Improved block performance, short administration time, reduced local anesthetic dosage, and rapid nerve blockage [9],[10].

  Aim Top

In the present randomized study, unilateral spinal anesthesia was compared with SFB in patients undergoing knee amputation surgery in terms of reliability of hemodynamic parameters, performance of the nerve block, function of the bladder, adverse effects, and readiness for discharge.

  Patients and methods Top

Patient population

Ethical approval and consent

This was prospective randomised study enrolled patients between 50 and 70 years of age with an American Society of Anesthesiologists clinical classification III–IV who were scheduled to undergo elective surgery for below-knee amputation. This study was carried out in El-Meqatt Hospital and Alhussien Hospital Al-Azhar University between January 2018 and December 2018 after obtaining informed and written consent and approval from ethics committee at the Faculty of Medicine at Al-Azhar University.

Consent of publication

All consents for publication have been taken.

Exclusion criteria

Allergies, bleeding disorders, acute infections, neurological disease, structural defects in the spinal cord, respiratory and heart disease, morbid obesity, and Allergy to local anesthesia were the exclusion criteria.

The patients were randomized into two classes using a computer-generated randomization table: group A and the SFB group B ([Figure 1]).
Figure 1 Consort chart.

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Outcome assessment

The primary outcome

The primary outcome of the experiment was block frequency with respect to sensory and motor blockade start and duration.

The secondary outcome

The secondary outcomes of the study were hemodynamic stability, postoperative analgesia, and incidence of complications.

Anesthetic procedure

Spinal anesthesia was achieved in the group A by injecting 2 ml (10 mg) of 0.5% levobupivacaine at the level of the lumbar L3–L4 through a 25-G spinal needle in the left or right lateral decubitus position for 15 min.

With the aid of an ultrasonic nerve stimulator (Fig. 2), the SFBs were obtained in the group B using a 25 ml mixture consisting of 10 ml of 2.0% lidocaine, 10 ml of 0.5% levobupivacaine, and 5 ml of saline (15 ml femoral and 10 ml sciatic nerve block).

For all patients, medical history and a complete physical examination are evaluated. Hemodynamic parameters were reported for ECG, systolic and diastolic blood pressures, and heart rate. Hypotension was treated by incremental intravenous doses of 3 mg ephedrine and intravenous fluid. Bradycardia was treated by 0.3–0.6 mg of intravenous atropine.

Surgical anesthesia time (SAT) in group A was described as complete sensory loss with complete motor blockage at 12-level thoracic. SAT was identified in group B as the complete motor block and sensory of the operated leg.

The ice cubes were used for the sensory block evaluation (onset and offset) and the sensor block reversal time. Pain severity was reported during skin incision and 60 min postoperative by visual analog scale.

Hemodynamic parameters were recorded at the start and every 5 min during operation and every 15 min postoperatively for 60 min.

Time-to-readiness for discharge was described as the period beginning at the end of the operation and ending when the patient’s condition was reported with stable vital signs capable of emptying urine, and nausea and pain could be controlled by oral medication.

Sample size estimation and power calculation

The sample size estimates were based on time-to-readiness for discharge. A sample size of 16 per group was estimated to provide 90% power to detect clinically significant 40 min difference at a meaning level of 0.05.

Statistical analysis

The statistical analysis was done using the statistical package for social sciences, version 20.0 (SPSS for Windows, version 17; SPSS Inc., Chicago, Illinois, USA). All data were expressed as means, standard variance, and frequency. Statistical significance was set at P value less than 0.05. Based on an independent t test, correlations between groups are made. The correlations were tested in groups using Fisher’s exact test and χ2 test.

The following tests were done:
  1. t significance independent samples were used when comparing two means.
  2. Mann–Whitney U test for nonparametric two-group correlations.
  3. The confidence interval was set at 95% and the agreed error margin was set at 5%. The P value was therefore regarded as meaningful as follows:
    • P value
      1. P value less than 0.05 was considered significant.
      2. P value less than 0.001 was considered as highly significant.
      3. P value more than 0.05 was considered insignificant.

  Results Top

The results of the present study are presented in the following tables and figures.

Regarding demographic data, no significant difference between the studied groups was found ([Table 1]).
Table 1 Demographic characteristics of the studied groups

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Regarding the onset of sensory and motor blocks, it was significantly shorter in group A compared with group B, whereas the recovery time for sensory and motor blocks was longer in group B compared with group A ([Table 2]).
Table 2 Comparison between groups according to operation time (min), onset of sensory block (min), onset of motor block (min), time for recovery from sensory block (h) and time for recovery from motor block (h)

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There was a decrease in time for spontaneous urination, increase in time for first analgesic need, and decrease in time to early discharge in group B as compared with group A, which was statistically significant ([Table 3]).
Table 3 Comparison between groups according to time-to-first spontaneous urination, time-to-first analgesic need and time-to-readiness for discharge

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Pain score was highly significant lower in group B compared with group A after surgery ([Table 4] and [Table 5]).
Table 4 Comparison between groups according to pain score after operation

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Table 5 Comparison between groups according to hemodynamic data

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[Table 5] shows no statistically significant difference between groups according to hemodynamic data.

There is a significant difference between group A and group B regarding patient satisfaction ([Table 6]).
Table 6 Comparison of patient satisfaction

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  Discussion Top

The purpose of this study is to explore the use of combined SFB with ultrasound guidance in comparison with unilateral spinal anesthesia in below-knee surgery. The present study found that SFB had some advantages over the unilateral spinal anesthesia including delayed time-to-first analgesic requirement, faster spontaneous urination, and shorter time-to-readiness for hospital discharge.

Previous research showed that ultrasound-guided SFB improved the block’s effectiveness compared with a neurostimulator alone [9]. The time of preparation for SFB was much longer in the present study than it was in the unilateral spinal anesthesia. The SAT in the unilateral spinal anesthesia was much shorter [11].

In the group B, the SAT was similar to values reported in studies using mepivacaine, despite the use of an agent with longer onset time of action such as levobupivacaine [7],[12].

In the present study, the total anesthesia time was found to be similar to those obtained in studies using 10 mg hypobaric and 7.5 mg hyperbaric levobupivacaine [13],[14]. In this study, the total anesthesia time of the group B was less than 50% compared with the values previously reported [15].

In the present study, SFB provided substantially more active analgesia than the unilateral spinal anesthesia at 4, 6, and 24 h after surgery.

Montes et al. [7] done Comparison of spinal anesthesia with combined sciaticfemoral nerve block for outpatient knee arthroscopy in his study subjects were equally divided (n=25 each) into spinal and sciatic-femoral groups. Spinal group patients received spinal anesthesia with 7.5 mg of 0.5% hyperbaric bupivacaine. Sciatic-femoral group patients received combined sciatic-femoral nerve blocks using a mixture of 20 mL of lidocaine 2% plus 20 mL of bupivacaine 0.5%. In the present study, the onset of sensory and motor blocks was significantly shorter in unilateral spinal anesthesia compared to femoral and sciatic nerve blocks. Whereas the recovery time for sensory and motor blocks was longer in femoral and sciatic nerve blocks compared to unilateral spinal anesthesia which agreement with Montes et al. Casati et al. [15]. compare the intraoperative and postoperative clinical properties of the sciatic nerve block performed with either 0.5% bupivacaine or 0.5% levobupivacaine for orthopedic foot procedures [14],[16]. Two previous studies suggested that SFB was effective and safe as spinal anesthesia without urinary retention [17],[18]. Another important factor is the discharge of patients who have been exposed to peripheral nerve block with longer periods of action due to pain deprivation due to lower extremity procedures called sensorial and protective reflexes [6].

An earlier study showed that this was a safe and effective procedure for this group of patients [19]. No adverse events were observed in this study after discharge, which according to the literature.

  Conclusion Top

SFB provided sufficient sensory blockage, duration, patient satisfaction, and postoperative analgesia than the unilateral spinal anesthesia.


The authors acknowledge all technical staff of general surgery and surgical operation theaters and patients who gave consent for enrollment for the study

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Ploeg AJ, Lardenoye JW, Vrancken Peeters MP, Breslau PJ. Contemporary series of morbidity and mortality after lower limb amputation. Eur J Vasc Endovasc Surg 2005; 29:633–637.  Back to cited text no. 1
Scott SW, Bowrey S, Clarke D, Choke E, Bown MJ, Thompson JP et al. Factors influencing short- and long-term mortality after lower limb amputation. Anesthesia 2014; 69:249–258.  Back to cited text no. 2
Aulivola B, Hile CN, Hamdan AD, Sheahan MG, Veraldi JR, Skillman JJ et al. Major lower extremity amputation: outcome of a modern series. Arch Surg 2004; 139:395–399.  Back to cited text no. 3
Ready BL. Acute perioperative pain. In: Miller RD ed. Anesthesia. 5th ed. Philadelphia: Churchill Livingstone; 2000. 2323–2350  Back to cited text no. 4
Spasiano A, Fllora I, Pesamosca A, Della Rocca G. Comparison between spinal anaesthesia and sciatic-femoral block for arthroscopic knee surgery. Minerva Anestesiol 2007; 73:13–21.  Back to cited text no. 5
Montes FR, Zarate E, Grueso R. Comparison of spinal anesthesia with combined sciatic-femoral nerve block for outpatient knee arthroscopy. J Clin Anesth 2008; 20:415–420.  Back to cited text no. 6
Cappellri G, Casati A, Fanelli G. Unilateral spinal anesthesia or combined sciatic-femoral nerve block for day-case knee arthroscopy. A prospective, randomized comparison. Minerva Anestesiol 2000; 66:131–136.  Back to cited text no. 7
Borghi B, Wulf H. Advantages of unilateral spinal anesthesia. Anasthesiol Intensivmed Notfallmed Schmerzther 2010; 45:182–187.  Back to cited text no. 8
Oberndorfer U, Marhofer P, Bosenberg A. Ultrasonographic guidance for sciatic and femoral nerve blocks in children. Br J Anaesth 2007; 98:797–801.  Back to cited text no. 9
Koscielniak-Nielsen ZJ. Ultrasound-guided peripheral nerve blocks: what are the benefits? Acta Anaesthesiol Scand 2008; 52:727–737.  Back to cited text no. 10
Casati A, Chelly JE, Cerchierini E. Clinical properties of levobupivacaine or racemic bupivacaine for sciatic nerve block. J Clin Anesth 2002; 14:111–114.  Back to cited text no. 11
Imbelloni LE, Drezendi GV, Ganem EM, Cordiro JA. Comparative study between combined sciatic-femoral nerve block, via a single skin injection, and spinal block anesthesia for unilateral surgery of the lower limb. Rev Bras Anestesiol 2010; 60:324–328.  Back to cited text no. 12
Cappelleri G, Aldegheri G, Danelli G. Spinal anesthesia with hyperbaric levobupivacaine and ropivacaine for outpatient knee arthroscopy: a prospective, randomized, double-blind study. Anesth Analg 2005; 101:77–82.  Back to cited text no. 13
Fanelli G, Casati A, Garancini P, Torri G. Nerve stimulator and multiple injection technique for upper and lower limb blockade: failure rate, patient acceptance, and neurologic complications. Study Group on Regional Anesthesia. Anesth Analg 1999; 88:847–852.  Back to cited text no. 14
Breebaart MB, Vercauteren MP, Hoffmann VL. Urinary bladder scanning after day-case arthroscopy under spinal anaesthesia: comparison between lidocaine, ropivacaine, and levobupivacaine. Br J Anaesth 2003; 90:309–313.  Back to cited text no. 15
Mulroy MF, Salinas FV, Larkin K. Ambulatory surgery patients may be discharged before voiding after short-acting spinal and epidural anesthesia. Anesthesiology 2002; 97:315–319.  Back to cited text no. 16
Casati A, Cappelleri G, Fanelli G. Regional anesthesia for outpatient knee arthroscopy: a randomized clinical comparison of two different anaesthetic tech-niques. Acta Anaesthesiol Scand 2000; 44:543–547.  Back to cited text no. 17
O’Donnell BD, Iohom G. Regional anesthesia techniques for ambulatory orthopedic surgery. Curr Opin Anaesthesiol 2008; 21:723–728.  Back to cited text no. 18
Klein SM, Nielsen KC, Greengrass RA, Warner DS, Martin A, Steele SM. Ambulatory discharge after long-acting peripheral nerve blockade: 2382 blocks with ropivacaine. Anesth Analg 2002; 94:65–70.  Back to cited text no. 19


  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


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