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Nir Hus MD, PhD., Absite review q8


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Slides with topics that are covered and were tested in the recent Absite exams.
Nir Hus MD., PhD.

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Nir Hus MD, PhD., Absite review q8

  1. 1. Absite Topic ReviewGeneral SurgeryNir Hus, MD, PhD.Mount Sinai Medical CenterMiami Beach
  2. 2. Post Op Neuropathy Nir Hus
  3. 3. Lower Extremity Neuropathies  most occur in patients who are undergoing procedures while in a lithotomy position.  considered preventable and to occur because of poor intraoperative care (for example, inappropriate positioning or padding) or judgment (for example, excessively prolonged use of the lithotomy position).  the nerves most often involved were:   The common peroneal (81%)   Sciatic (15%)   Femoral (4%). Nir Hus
  4. 4. Common Peroneal Neuropathy  The common peroneal nerve is superficial as it wraps around the head of the fibula. Because it is exposed at this level, it may be easily compressed and injured.  The absence of overlying tissue in extremely thin people may increase this risk.  Direct compression of the peroneal nerve by leg holders has commonly been considered the primary mechanism of injury in peroneal neuropathy. Nir Hus
  5. 5. Nir Hus
  6. 6. Sciatic Neuropathy  The same forces that contribute to stretch injuries of the hamstring group muscles (for example, biceps femoris muscle) may stretch the sciatic nerve.  Simultaneous hyperflexion of the hip and extension of the knee will stretch and possibly injure the sciatic nerve.  This set of actions can occur during the establishment and maintenance of some variants of the lithotomy position.  A patient in a lithotomy position may passively shift toward the caudal end of an operating table when placed in a head-up position or be actively shifted caudally by a member of the operating team in an attempt to obtain increased exposure of the perineum.  This movement may increase flexion of the hips and either flexion or extension of the legs Nir Hus
  7. 7. Femoral Neuropathy  Unlike most other neuropathies in which the anesthesia provider is often considered to have acted inappropriately in order for the neuropathy to occur, those involving the femoral nerve and its cutaneous branches are often considered to result from inappropriate placement of abdominal wall retractors and direct compression of the nerve.  When a neuropathy is related to retractors, the assumption is that a retractor used for an abdominal surgical approach to the pelvis places continuous pressure on the iliopsoas muscle and either stretches the nerve or causes it to become ischemic by occluding the external iliac artery or its branches (or both) that penetrate the nerve as it passes through the muscle Nir Hus
  8. 8. Nir Hus
  9. 9. Upper Extremity Neuro  Any nerve that passes into the upper extremity may sustain an injury or convert from an abnormal but asymptomatic state to a symptomatic state perioperatively.  The ulnar nerve and brachial plexus nerves are the most likely to become symptomatic and lead to major perioperative disability. Nir Hus
  10. 10. Median Neuropathy  This injury occurs most often in muscular men in the young to middle-age groups.  Preoperatively, these patients often are unable to extend their arms completely at the elbows because their large biceps muscles and tendons are relatively inflexible.  When they receive muscle relaxants, undergo anesthesia, and are positioned for an operation, their relaxed forearms may be extended flat onto arm boards or at their sides; consequently, their median nerves may be stretched. . Nir Hus
  11. 11. Ulnar Neuropathy  Currentlyavailable data suggest that perioperative ulnar neuropathy may be caused by factors other than inappropriate patient positioning and padding of extremities intraoperatively. Nir Hus
  12. 12. Ulnar Neuropathy   Ulnar nerve and its primary blood supply in proximal forearm, posterior ulnar recurrent artery, are superficial and can be susceptible to compression from external pressure as they pass posteromedially to tubercle of coronoid process. Nir Hus
  13. 13. Brachial Plexus Neuropathy  may masquerade as ulnar neuropathies or be associated with symptoms that suggest injuries to other nerve structures.  In general, brachial plexus neuropathies are associated with:   median sternotomy.   Head-down positions in which shoulder braces are used for support and stabilization.   Rarely, they may be found in patients in a prone position. Nir Hus
  14. 14. Brachial Plexus Neuropathy  Neuropathy associated with median sternotomy often involves stretch or compression of the brachial plexus during sternal separation.  Another potential mechanism of injury is direct trauma from fractured first ribs.  Brachial plexus nerve injury during sternal retraction is most common during internal mammary artery dissection. Nir Hus
  15. 15. Brachial Plexus Neuropathy  Retraction posteriorly displaces the upper rib cage and may stretch or compress the C-8 through T-1 nerve trunks.  These nerve trunks later join to form the major contribution of the ulnar nerve.  Therefore, this brachial plexus neuropathy may be difficult to distinguish from a peripheral ulnar neuropathy. Nir Hus
  16. 16. Brachial Plexus Neuropathy  The brachial plexus may be vulnerable to stretch in a patient who is positioned prone.  Theoretically, stretch of the plexus, especially its lower trunks, may occur when the head is turned contralaterally, the ipsilateral arm is abducted, and the ipsilateral elbow is flexed Nir Hus
  17. 17. Brachial Plexus NeuropathyHead position stretching plexus against anchors in shoulder (A). Closure ofretroclavicular space by chest support with arms at side; neurovascular bundle trappedagainst first rib (B). Head of humerus thrust into neurovascular bundle if arm and axillaare not relaxed (C). Compression of ulnar nerve in cubital tunnel (D). Area ofvulnerability of radial nerve to compression above elbow (E). Nir Hus