Characteristics of Popliteal Sciatic Nerve Block in Patients With and Without Diabetic Neuropathy
Condition: Diabetic Neuropathy
MeSH terms: Diabetic Neuropathies
Study type: Interventional

Summary: 
      Background Between 25 and 55% of diabetic patients develop neuropathy secondary to
      hyperglycemia. High resolution bedside ultrasound has been demonstrated to be a useful tool
      to detect the presence of neuropathy prior to block performance, by measuring the
      cross-sectional area of the posterior tibial nerve: a value superior to 19.01 mm2 at a
      distance of 3 cm above the medial malleolus has an optimal threshold value for identification
      of diabetic sensorimotor polyneuropathy.

      Animal data showed that duration of sciatic nerve block with local anesthetics is longer in
      diabetic rats compared with non-diabetic rats. Characteristics of a peripheral nerve blockade
      in humans with diabetic sensorimotor neuropathy are unknown.

      Aim The aim of this study is to compare duration of analgesia and other characteristics of an
      ultrasound-guided popliteal sciatic nerve block between diabetic patients with neuropathy,
      diabetic patients without neuropathy and non-diabetic patients without neuropathy, based on
      the ultrasound-measured cross-sectional area of the posterior tibial nerve.

      Hypothesis We hypothesize that diabetic patients with neuropathy will have a duration of
      analgesia lasting 50% longer than patients without neuropathy.

      Methods This will be an observational study on diabetic and non-diabetic patients, with and
      without peripheral neuropathy, based on the ultrasound-measured cross sectional area of the
      posterior tibial nerve 3 cm above the medial malleolus (cut-off value, 19.01 mm2)

      All patients will receive ultrasound-guided sciatic nerve block with 30 mL1:1 mixture of
      lidocaine 1% and bupivacaine 0.5%, with the needle tip positioned at the bifurcation of the
      sciatic nerve in peroneal and tibial nerve, below the common fascia or paraneurium. Block
      success will be confirmed by loss of sensation to pinprick in the distribution of the common
      peroneal and tibial nerves 30 minutes following local anesthetic injection. This procedure
      will be completed by a saphenous nerve block. Postoperative pain management will be
      standardized.

      Pain and block-related endpoints will be collected such as onset time of action of sensory
      and motor blockades, duration of analgesia, pain scores and opiates consumption among others.

      Relevance Defining the duration of analgesia in case of diabetic neuropathy will help
      regional anesthesiologists to better define the type and doses of drugs that will be injected
      and to better prescribe the postoperative multimodal analgesic treatment.
    


Intervention name(s): US-guided sciatic block at the popliteal crease (30 mL1:1 mixture of lidocaine 1% and bupivacaine 0.5%)
Intervention type(s): Procedure
Intervention MeSH terms: Lidocaine; Bupivacaine
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Regional anesthesia; Diabetic neuropathy; Ultrasound