Efficacy and Safety of Obturator Nerve Block During Transurethral Resection on Non-muscle Invasive Intermediate and High Risk Lateral Wall Bladder Tumours
Condition: Bladder Cancer Stage 0; Bladder Cancer Stage I
MeSH terms: Urinary Bladder Neoplasms
Study type: Interventional

Summary: 
      In this prospective randomized controlled study, the effects of obturator nerve block (ONB)
      on obturator reflex, incomplete resection, perforation, tumor recurrence and progression,
      presence of muscle tissue in the specimen, need for second transurethral resection of bladder
      tumours (TURBT) and postoperative complications were investigated in patients who underwent
      TURBT for intermediate and high risk lateral wall non-muscle invasive bladder tumours
      (NMIBC).
    

Detailed description: 
      Bladder cancer is among the ten most common types of cancer in the world, with about 550,000
      new cases per year. According to GLOBOCAN (Global Cancer Incidence, Mortality and Prevalence)
      data, bladder cancer accounts for 3% of cancer diagnoses worldwide. It is more common,
      especially in developed countries. A total of 90% of bladder cancer diagnoses are made in
      people 55 years of age or older, and the disease is four times more common in men than in
      women. NMIBC are divided into four groups as low-medium-high and very high risk according to
      EORTC (European Organization for Research and Treatment of Cancer). Early recurrence was
      reported as 15%, late recurrence as 25% and progression as 9% with BCG treatment in medium
      and high risk NMIBC. TURBT is the basic approach in diagnosis and treatment.

      The obturator nerve passes through the obturator foramen of the pubis and innervates the
      adductor muscles of the thigh. It lies within the pelvic cavity close to the prostatic
      urethra, bladder neck and inferolateral bladder wall. In TURBT, when the bladder is filled
      with irrigation fluid, the obturator nerve is very close to the bladder sidewall. While
      performing TURBT of lateral wall bladder tumors, neighboring obturator nerve stimulation may
      occur during surgical resection, resulting in adductor contraction and leg jerking. This
      condition, called the obturator reflex, occurs between 55.3% and 100% of lateral bladder
      tumors.

      Serious complications can occur in TURBT, one of which is bladder perforation that may
      require laparotomy and open repair. Perforation is also associated with poor patient outcomes
      due to the spread of the tumor into the abdominal cavity and the inability to apply single
      immediate instillation of intravesical chemotherapy. One of the most important factors
      affecting the success of TURBT is the presence of residual tumor as a result of incomplete
      resection. Incomplete resection is associated with both general recurrence and particularly
      local recurrence, as well as shortening disease-free survival. One of the most important
      indicators of complete resection is the presence of the detrusor muscle in the TURBT
      specimen. However, in 10% of all cases, it has been reported that there is no detrusor muscle
      tissue in the TURBT specimen. Various methods such as administration of muscle relaxants
      under general anesthesia, less filling of the bladder, reduction of electric current, using a
      90-degree classical loop, using bipolar plasmakinetic energy and performing tumor resection
      with small pieces have been proposed in order to prevent the failure and complications due to
      obturator reflex that may occur in TURBT.

      In combination with spinal anesthesia, ONB is one of the most effective methods used to
      inhibit the obturator reflex. The importance of spinal anesthesia has increased especially
      due to the COVID-19 outbreak. Surgery under local / regional anesthesia is recommended as
      much as possible, especially during the pandemic process, compared to general anesthesia. In
      this way, it is aimed to reduce the risk of aerosol generating procedures and subsequent
      viral transmission. ONB has gained more importance in recent years as a result of being
      performed together with spinal anesthesia.
    

Intervention name(s): Nerve Stimulator-guided Obturator Nerve Block
Intervention type(s): Procedure
Intervention description(s): Following the confirmation of spinal anesthesia level in the patients in the ONB group while in the lithotomy position, ONB was applied unilaterally or bilaterally, depending on the tumor position. A needle with a nerve stimulator was advanced vertically 2 cm below and 2 cm from the pubic tubercle. The needle is inserted through the skin and into the lower ramus of the pubic bone. When contraction was observed in the adductor muscle groups and the aspiration was negative, 10 mL 0.25% levobupivacaine at 0.3-0.5 mA was administered. The operation was started 10 minutes after the injection. TURBT operations were performed with a 30 degree optic and a 26 F bipolar resectoscope. All spinal anesthesia and ONB procedures were performed by the same anesthesia team. All TURBT operations were performed by the same surgeon.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Non-muscle invasive bladder cancer; Obturator nerve block; Transurethral resection