Objectives: To assess the efficacy and safety of spinal anesthesia combined with obturator nerve block (ONB) for transurethral resection of bladder tumor. Subjects and methods: A prospective study was carried out on 10 patients who underwent spinal anesthesia combined with ONB using nerve stimulation for transurethral resection of bladder tumor.
JOURNAL OF MILITARY PHARMACO-MEDICINE N07-2016 INITIAL ASSESSMENT OF EFFICACY AND SAFETY OF SPINAL ANESTHESIA COMBINED WITH OBTURATOR NERVE BLOCK FOR TRANSURETHRAL RESECTION OF BLADDER TUMOR Nguyen Trung Kien*; Hoang Van Chuong*; Tran Van Hinh* Nguyen Phu Viet*; Pham Quang Vinh* SUMMARY Objectives: To assess the efficacy and safety of spinal anesthesia combined with obturator nerve block (ONB) for transurethral resection of bladder tumor Subjects and methods: A prospective study was carried out on 10 patients who underwent spinal anesthesia combined with ONB using nerve stimulation for transurethral resection of bladder tumor Quality of anesthesia, violent adductor contraction and inadvertent bladder perforation as well as side effects were monitored Results: All patients had an excellent quality of anesthesia, distance from skin to obturator nerve was 2.6 ± 1.4 cm on everage, patients were absent of leg jerking Side effects included shiving in cases, hypotension in case and bradycardia in case Conclusion: Combination of spinal anesthesia and ONB provided good effective anesthesia for transurethral resection of bladder tumor: adductors muscle spasms were absent in 90%, side effects were transient and mild * Key words: Bladder tumor; Spinal anesthesia; Obturator nerve block; Transurethral resection of bladder tumor INTRODUCTION Bladder cancer is the fourth most common cancer in men in the world The obturator nerve may be accidentally stimulated during transurethral resection of lateral bladder wall tumors, causing adductor contraction Spinal anesthesia is a favoured anaesthetic technique but the rate of adductor spasm can get as high as 40% [3] That is also the main reason leading to bladder wall perforation and increase morbidity Methods of preventing the stimulation of the obturator nerve include: reduction of the electrocautery power, bipolar resection, general anesthesia, or ONB following spinal anesthesia [8] The objective of this study is: To assess the efficacy and safety of combination of spinal anesthesia and ONB for transurethral resection bladder tumor SUBJECTS AND METHODS Methods A prospective study was conducted from - 2015 to - 2016 to assess the efficacy and safety of combination of spinal aneshthesia and ONB using nerve stimulator in 10 patients who underwent transurethral resection bladder tumor - The patients were admitted into operating room, and established intravenous access for 0.9% of NaCl infusion Constant monitoring was ensured of ECG, heart rate, pulse oxymetry (SpO2); non-invasive blood pressure measurements were taken every 2.5 minutes; oxygen was delivered 3l/mins via facemask * 103 Hospital Corresponding: Nguyen Trung Kien (drkien103@gmail.com) 66 JOURNAL OF MILITARY PHARMACO-MEDICINE N07-2016 - Spinal anesthesia was performed in the sitting position, most frequently in the L3-L4 or L2-L3 space with the dose of 10 mg of hyperbaric bupivacaine 0.5% depending on the patient’s status and 20 mcg of fentanyl Betadine was used for skin antisepsis before inserting the spinal needle - 25G spinal needle was inserted, when cerebral spinal fluid was free, the mixture of bupivacaine - fentanyl was slowly injected into intrathecal space and then placed in the supine position - Bilateral ONB was then performed: a 100 mm long stimuplex needle (B Braun, Melsungen, Germany) that was connected to a stimulating current at mA was inserted cm caudally and laterally to the pubic tubercle The needle was then slowly introduced below the horizontal remus of the pubis and inserted deeper until its tip laid in the obturator canal The optimal needle position was reached when the minimal stimulating current (< 0.5 mA) induced adductor spasm Once this position was reached, 10 mL of 2% lidocaine were injected The whole procedure was repeated on the other side blocked conduction in the sensory nerve fibers of the bladder, the patient was placed in the obstetric position - The quality of anesthesia was judged on a point scales as: + Excellent: no pain or sensation + Good: mild pain or discomfort + Fair: mild discomfort that required analgesia + Poor: patient in moderate or severe pain that required general anaesthesia - The duration of spinal anaesthesia was defined as the period from spinal injection to the first time when the patient requested for analgesia in the postoperative period - Monitor degree of motor block by Bromage scale: + Grade 0: no motor block + Grade 1: inability to raise extended leg; able to move knees and feet + Grade 2: inability to raise extended leg and move knee; able to move feet + Grade 3: complete block of motor limb - Monitor the distance from skin to the abturator nerve; quality of ONB - Transurethral resection bladder tumor procedure was performed + Good: no reflexes from the obturator nerve during procedure - Materials and devices: stimulex HNS 12, B.Braun; 100 mm long stimulex needle; monitor Nihon Kohden (Japan) + Bad: had any reflexes from the obturator nerve during procedure, bladder perforation during electroresection and other complications Some terms were used in the study - Sensory block level on the skin was assessed by Pin-prick test Upon reaching the appropriate anesthesia level T10, which - Hypotension is difined as a fall in blood pressure of more than 20% below the preoperative blood pressure or a mean arterial pressure of less than 60 mmHg 67 JOURNAL OF MILITARY PHARMACO-MEDICINE N07-2016 RESULTS Patient and surgical demographics Table 1: Patient and surgical demographics Result (n = 10) Gender: male/female Age (mean ± SD) BMI (kg/m ) (mean ± SD) ASA grade: 1/2/3/4/5/6 8/2 48.5 ± 17.6 [42 - 69] 21.3 ± 3.4 [18.2 - 24.8] 4/3/2/0/0 Duration of taking ONB (minutes) (mean ± SD) 5.4 ± 3.7 [2.5 - 8.3] Distance from skin to obturator nerve (cm, mean ± SD) 2.6 ± 1.4 [2.3 - 4.2] Bilateral ONB/unilateral ONB block 10/0 Bromage score 0/1/2/3 ten minutes after spinal block 0/0/0/9 Quality of spinal anesthesia (n) Excelent/good/mild/fair 10/0/0/0 Duration of spinal anesthesia (minutes) (mean ± SD) 226.8 ± 37.5 Other perioperative characteristics Table 2: Result Adductor muscle contraction n (%) No (90%) Moderate (10%) Severe Operation time (minutes, mean ± SD) 22.7 ± 9.3 [18 - 32] Tumor size (mm) (mean ± SD) 5.2 ± 4.9 [2 - 12] Tumor number (n) (mean ± SD) 2.1 ± 1.7 [1 - 4] Bladder perforation (n) (%) Complete resection (n) (%) Yes (90%) No (10%) Vital signs Respiratory rate, pulse oxymetry (SpO2,), pulse rate, blood pressure were stable and ranged in normal limitation * Complications and side effects (n = 4): Shivering: patients (20%); hypotension: patients (10%); bradycardia: patients (10%); nausea: patients (0%); anesthetic toxicity: patients (0%) 68 JOURNAL OF MILITARY PHARMACO-MEDICINE N07-2016 DISCUSSION An advantage of spinal anesthesia is that profound nerve block can be produced in a large part of the body by the relatively simple injection of a small amount of local anesthesia This technique is commonly used for transurethral resection of the bladder tumor Also it has an adequate quality of anesthesia for most kinds of intervention in urology, but it can not prevent bladder perforation from contracting adductor due to stimulating during transurethral resection of lateral bladder wall tumors Transurethral resection of bladder tumors which are close to these areas may stimulate the obturator nerve, causing violent adductor contraction and possible inadvertent bladder perforation To avoid this reaction, local anesthetic blockade of the obturator nerve as it passes through the obturator canal is effective in stopping adductor spasm during spinal anesthesia [4] Thus, we had an initial assessment efficacy of spinal anesthesia combined with ONB for this kind of surgery at 103 Hospital In our study, mean age was in labour age and male had a higher rate than female The distance from skin to obturator nerve was 2.6 ± 1.4 cm on the sagittal plane and the pubic tubercle (Table 1) This result is similar to Locher’s results when he studied in ten cadavers (ranged from to 3.8 cm) [6] There were 10 patients who needed bilateral ONB because two sides wall bladder of the tumor located; of which patients had not seen adductor muscle contraction, but case still had slight contraction of adductor muscle although the quality of anesthesia was excellent in all patients (table 2) According to Bolat (2015) [3], adductor muscle contraction was detected in 40% of patients in group with spinal anesthesia but just only 11.4% in group combined spinal anesthesia with ONB The mechanism of adductors’ contraction during this procedure have been studied The sensorimotor nerve arises from the lumbar plexus at L2-L4 and in the lesser pelvis, it is adjacent to the obturator fascia, which covers the outer part of the internal obturator muscle It innervates the muscles responsible for adducting the thigh and the skin on the surface of the paramedian segment of the thigh During transurethral resection of the bladder tumor, when the bladder has been filled with irrigation fluid, the obturator nerve is directly adjacent to the lateral wall of the bladder Any unintentional stimulation during electroresection results in the adductors’ contraction and resultant sudden leg movement, which may in turn lead to extraperitoneal perforation of the bladder wall with the resectoscope loop Adductors’ contraction during transurethral resection can cause major complications such as bladder perforation, obturator artery injury We did not have any complications due to small size of study (n = 10) Akata T had a case report with life-threatening haemorrhage following obturator artery injury during transurethral bladder surgery as a sequel of an unsuccessful ONB According to this result, in spite of prior blockade of the obturator nerve with 1% mepivacaine (8 mL) utilizing a nerve stimulator, violent leg jerking was evoked during transurethral electroresection of a bladder tumor approximately hour after the blockade He noticed that the patient became severely hypotensive right after following the jerking, and a large lower 69 JOURNAL OF MILITARY PHARMACO-MEDICINE N07-2016 abdominal swelling concurrently developed The urgent laparotomy indicated that the left obturator artery was severely injured by the resectoscope associated with the bladder perforation, causing acute massive haemorrhage [1] Thus, combining spinal anesthesia with ONB brought much benefit for this procedure Volume and concentration of anesthetic solution are important factors for getting success in prevention of the obturator nerve stimulation during the transurethral procedures We had an unsucessfull case because in this patient we injected two sites and this was not enough anesthetic solution to cover obturator nerve Akata T [1] found that, in order to attain profound blockade of the motor neuron fibres of the obturator nerve and thereby prevent the thigh-adductor muscle contraction which could lead to life-threatening situations, larger volume of a higher concentration of local anaesthetic with a longer duration should be used, even with a nerve stimulator, in the ONB for the transurethral procedures But failure in ONB was sometimes due to accessory obturator nerve that was presented in 10 - 30% of patients Thus, it was clinically important that it was also considered during ONB According to Akkaya [2], the mean accessory obturator nerve-pubic tubercle distance was cm When the needle was classically penetrated into the obturator nerve to gain access to the accessory obturator nerve Obturator nerve could be blocked through inguinal approach or intravesical approach which had a different result in block We assessed this nerve via 70 inguinal approach and the rate of success was 90% In Tatlisen A’s study [7], muscle spasms were absent in 97% (n = 61) with nerve stimulation guided for ONB Another study by Hizli F [4] was carried out on 41 patients who underwent transurethral resection of bladder tumor with spinal anesthesia combined with ONB After spinal anesthesia, ONB was performed with an inguinal approach (n = 21) or an intravesical approach (n = 20) In this study, 10 ml of 2% lidocaine was used to perform the ONB The efficacy of ONB was significantly higher in inguinal approach group compared to intravesical approach group The study by Khorrami M [5] has shown that ONB using stimulation guided took 5.2 to 6.7 minutes on everage This time in my study was 5.4 ± 3.7 minutes In general, it’s more accurate to determine the obturator nerve with nerve stimulation rather than blind technique Complications were not seen in the study Side effects were transient and mild included shiving 20%, hypotension 10%, bradycardia 10% CONCLUSION Combination of spinal anesthesia and ONB provided good effective anesthesia for transurethral bladder tumor surgery: adductors muscle spasms were absent in 90%, side effects were transient and mild REFERENCES Akata T, Murakami J, Yoshinaga A Lifethreatening haemorrhage following obturator artery injury during transurethral bladder surgery: a sequel of an unsuccessful ONB Acta Anaesthesiol Scand 1999, 43 (7), pp.784-748 JOURNAL OF MILITARY PHARMACO-MEDICINE N07-2016 Akkaya T, Comert A, Kendir S, Acar H.I, Gumus H, Tekdemir I, Elhan A Detailed anatomy of accessory obturator nerve blockade Minerva Anestesiol 2008, 74 (4), pp.119-122 Bolat D, Aydogdu O, Tekgul Z.T, Polat S, Yonguc T, Bozkurt I.H, Sen V, Okur O Impact of nerve stimulator-guided ONB on the short-term outcomes and complications of transurethral resection of bladder tumour: A prospective randomized controlled study Can Urol Assoc J 2015, (11 - 12), pp.E780-4 Hizli F, Argun G, Guney I, Guven O, Arik A.I, Basay S, Gunaydin H, Basar H, Kosus A ONB transurethral surgery for bladder cancer: comparison of inguinal and intravesical approaches: prospective randomized trial Ir J Med Sci 2015 Khorrami M, Hadi M, Javid A, Izadpahani M.H, Mohammadi Sichani M, Zargham M, Alizadeh F A comparison between blind and nerve stimulation guided ONB in transurethral resection of bladder tumor J Endourol 2012, 26 (10), pp.1319-1322 Locher S, Burmeister H, Bohlen T, Eichenberger U, Stoupis C, Moriggl B, Siebenrock K, Curatolo M ONB: a technique based on anatomical findings and MRI analysis Pain Med 2008, (8), pp.1012-1015 Tatlisen A, Sofikerim M ONB and transurethral surgery for bladder cancer Minerva Urol Nefrol 2007, 59 (2), pp.137-141 Wassef M.R Interadductor approach to obturator nerve blockade for spastic conditions of adductor thigh muscles Reg Anesth 1993, 18 (1), pp.13-17 71 ... out on 41 patients who underwent transurethral resection of bladder tumor with spinal anesthesia combined with ONB After spinal anesthesia, ONB was performed with an inguinal approach (n = 21)... the obturator canal is effective in stopping adductor spasm during spinal anesthesia [4] Thus, we had an initial assessment efficacy of spinal anesthesia combined with ONB for this kind of surgery... injection of a small amount of local anesthesia This technique is commonly used for transurethral resection of the bladder tumor Also it has an adequate quality of anesthesia for most kinds of intervention