Can Ultrasound Predict Nerve Injury Following Posterior Tibial Nerve Block in Patients With Peripheral Neuropathy?
Condition: Diabetic Neuropathy
MeSH terms: Peripheral Nervous System Diseases; Diabetic Neuropathies
Study type: Observational

Summary: 
      The use of regional anesthesia for nerve block in diabetic patients with peripheral
      neuropathy is currently made on a case-by-case basis, also remains underlying uncertainty
      regarding the preferred technique and the likelihood of block-related nerve injury. For this
      many diabetic patients with otherwise healthy nerves may receive general anesthesia instead
      of regional anesthesia, thus giving up the benefits associated with the latter technique,
      including a decrease in health complications and superior analgesia following the operation.
      Ultrasound is used to identify the target nerve and guide needle insertion for nerve blocks,
      may be a useful tool to detect the presence and severity of neuropathy prior to block
      placement, a recent study demonstrated a statistically significant increase in the
      sonographic cross-sectional area of the posterior tibial nerve (PTN) in all diabetic patients
      who had abnormal motor transmission on nerve conduction studies. For regional
      anesthesiologists, the ultimate goal of detecting peripheral neuropathy and in particular,
      diabetic neuropathy by US is to avoid nerve injury. To do so, the association between
      US-detected diabetic neuropathy and block-related nerve damage must be first established,
      hence the purpose of this study. We aim to examine whether the cross-sectional area of PTN as
      assessed by preoperative US can predict nerve injury as assessed by worsening nerve
      conduction studies following PTN block inpatients scheduled to receive an ankle block. A
      further subgroup analysis will be performed in diabetic patients.

      We hypothesize that the cross sectional area of the PTN will correlate with motor conduction
      velocity on nerve conduction studies (NCS) following PTN block in patients with peripheral
      neuropathy. All eligible patients will undergo NCS to confirm or exclude distal neuropathy.
      Patients without neuropathy will be excluded from further participation in this study. Also
      excluded will be diabetic patients with neuropathy caused by genetic, metabolic and
      inflammatory diseases as well as toxic agents and drug induced. A systematic US examination
      of the PTN will be performed for all patients. After Block administration at surgery day the
      block successes will be assessed and for the purposes of the present study, patients in whom
      the block was not successful will be excluded from further intervention and data analyses.
      Eight weeks after surgery, all study patients will return to hospital for repeat NCS and US.
    


Intervention name(s): Nerve conduction study and Ultrasound of the PTN
Intervention type(s): Procedure
Intervention description(s): Nerve Conduction studies and ultrasound of PTN will be performed to the patient before the operation and 8 weeks postoperatively.
Observational model: Other
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Diabetic and non-diabetic patients undergoing foot surgery involving regional
        anesthesia/nerve blockade.
      
Keywords: diabetes; neuropathy; ankle block; regional anesthesia; ultrasound; nerve localization; Nerve localization in patients undergoing foot surgery and having ankle block