PERIPHERAL SYMPATHETIC BLOCKS

1. PERIPHERAL SYMPATHETIC BLOCKS R1이승일

2. Stellate ganglion block • Anatomy Cervical sympathetic trunk는 three interconnected ganglia로 구성: sup.,mid.,inf. Cervical ganglia 80%사람들은 lowest cervical ganglion이 first thoracic ganglion과 fuse되어 cervicothoracic(stellate)ganglion을 형성 - 대개 C7 transverse process 기시부와 T1 첫번째 늑골두앞 사이에 위치, 앞으로는 common carotid a.,subclavian a., thyroid gl., SCM, 뒤로 prevertebral fascia가 있다 cervical ganglia는 spinal cord의 lat. Gray column으로부터 preganglionic fiber를 받는다 Preganglionic fiber for the head and neck emerge from the upper five thoracic spinal nerves ascending in the sympathetic trunk to synapse in the cervical ganglia Preganglionic fibers supplying the upper limb originate from the upper thoracic segment, T2~6 ascend via the sympathetic trunk to synapse in the cervicothoracic ganglion, where postganglionic fibers pass to the brachial plexus

3. Effects of SGB • Pph.vasodilatation – blood flow증가, brain blood flow증가 Lt SGB - HR증가, BP증가,activate sympathetic neural outflow to skeletal m.(no deterious effect on lt.ventricular function), QT interval 감소 Rt SGB – sympathetic, parasympathetic activity증가로 RR interval 변화 유발 * increase retinal venous blood velocity without changing the retinal vessel diameter * Block side의 intraocular pr. & oxygen tension & temperature 감소, tympanic temp.도 감소할수 있는데 SGB 5분 후에 발생하여 30분 이상 지속 할수있다 기전은 명확치 않으나 immune, endocrine systems에 대한 영향도 있는 것으로 되어있음

4. Clinical indications for cervicothoracic ganglion block • Complex regional pain syndrome • Acute pain of herpes zoster • Postherpetic neuralgia • Acute and chronic vasculaopathies of the head, neck and upper extremity …etc

5. technique • Iv line & resuscitative equipment • Supine position with the head slightly lift forward and tilted backwards to straighten the esophagus and move it away from the transverse processes - mouth is slightly opened to relax the neck muscle - cricoid cartilage palpation to discern the level of the C6 transverse process - Identify Chassaignac’s tubercle at C6(located approximately 3cm cephalad to the S-C joint at the medial border of the SCM and trachea)

6. fig80-1

7. carotid a. retraction • 22g short beveled 4 to 5 cm needle is advanced downward perpendicular to the table plane, until it touches bone and then withdrawn approximately 2mm to avoid inj. Into the periosteum • Needle is contact with C6 tubercle • C6 tubercle is covered by the prevertebral fascia whereas the longus colli m. is located at the lat. aspect of the body of the vertebra and the medial aspect of the transverse process • Longus colli부위에 inj.하면 muscle course를 따라 spread 됨 • Fluoroscopy를 이용, 1to 2mL of contrast material을 이용하여 needle placement를 확인할수도 있다 • The choic of medication and the vol. of the solution – vary according to the preference of the physician

8. Alternative approaches C7 anterior approach - c7은 vestigial tubercle을 가지고 있으므로 c6을 먼저 확인하고 one finger caudally하게 c7 transverse process가 위치 이때 더 less volume is needed to achieve a sympathetic blockade – vertebral a. puncture가능성과 pneumothorax가능성이 있음 Posterior thoracic approach • Fluoroscopy 나 CT guidance하에 needle 을 2 ~4cm lat. to the upper thoracic spinous process 로 주입, lamina contact후 moved laterally off the lamina, parallel to the sagittal plane, lamina를 지나 2cm깊이의 costotransverse lig.까지 진입 – loss of resistance technique Side effects and complications - properly performed, SGB is safe and easy procedure complication are rare ( incidence of 0.17%)

9. LUMBAR PARAVERTEBRAL SYMPATHETIC BLOCK • Anatomy sympathetic chain은 lumbar vertebral body의 anterolateral surface를 따라 놓임 lumbar sympathetic chain 은 pelvis, lower extremity로 가는 pre, post ganglionic fiber를 지닌다 Lower extremity의 sympathetic innervation이 origin하는 곳은 2,3 lumbar vertebral body level의 sympathetic ganglia(lower third of the second lumbar vertebra, at the upper third of the third lumbar vertebra) The best site for placement of the tip of the needle is the anterolateral surface of the lower second vertebral body or at the upper third of the third vertebral body * segmental a. & vein이 dense fascia아래의 tunnel로 midportion of the lumbar verteral body를 통해 지나가므로 solution이 이 터널을 통해 epidural space로 유입 될수 있음에 유의

10. Indication • Sympathetic mediated pain • Improvement of blood flow in pt. with vascular insufficiency of their lower extremities • Management of neuralgic pain associated with pph.nerve injuries

11. Technique • Earlier technique- L2,3,4 inj.이었으나 최근 single needle사용 • prone position, pillow underneath the lower abdomen(to reduce lumbar lordosis) • Hatangdi and Boas technique - 12the rib의 tip을 palpation(on the side to be injected), tip 12th rib의 2~3cm below and medial 하게 needle insertion(L3) 5~7inch 22g needle 을 midline에서 8~10cm, 30~45도 angle로 lateral to the spinous process하게 anterolateral aspect of the vertebra에 도달할때까지 진입- contrast를 이용하여 needle placement확인 – 15~20ml local anesthetic inj.

12. fig 80-2 fig80-3

13. neulolytic block • Two needle technique( L2 & L3) 2~4ml of 6% phenol inj. at each site • Needle 제거 직전에 1ml의 air or local anesthetic주입(neurolytic solution의 depositioning예방) • Patient is kept on the side for 15~30min. > To prevent the phenol from spreading laterally toward the genitofemoral n. or posteriorly toward the somatic nerve roots, then turned supine and instructed not to raise head for at least 1 hours complication of lumbar paravertebral sympathetic block - bleeding , hematuria, infection, orthostatic hypotension, perforation of the abdominal viscera, epidural or subarachnoid blockade, lumbar plexus block, segmental nerve injury

14. Ch.81 Complications after peripheral nerve block

15. Death, cardiac arrest, resp.arrest, permanent neurologic injury 는 neuraxial block에서 의미있게 더 많이 일어남 – PNB에서 는 매우드물다 • PNB의 가장serious complication은 intravascular inj. of local anesthetic 또는 peripheral n. injury이다. 대개 large volume of local anesthetic에 기인 • Neurologic injury는 subarachnoid block에 비해 적다 • PNB의 시행은 비교적안전하나 life altering complication의 potential은 여전히 있음에 유의

16. Table 81-1

18. Vascular complications • Intravascular injection - pph.block시행중 vascular landmarks의 사용은 unintentional intravascular inj. Of local anesthetic를 유발할가능성을 높인다 : transarterial axillary block시 careful aspiration, test dosing후에도 약0.2%에서 intravascular inj. 이 발생 • Direct intra arterial inj. Vs intravenous inj. - 전자는 후자에비해 소량의 bupivacaine,lidocaine에도 seizure를 유발할수 있으나 후자는 lung 과 whole body를 통해 distribution , clearing되면서 seizure발생빈도가 줄어듬 Subcutaneous or interstitial tissues에서 uptake된 local anesthetic 의 Peak plasma level 은 30~60분 까지 지연될수 있으며 이는 total local anesthetic dose, vasoconstrictor, block site에 영향받음 - delayed toxicity의 risk는 intercostal n. block > plexus block > local subcutaneous infiltration의 순으로 낮아짐 - intravascular inj.의 예방 -> frequent aspiration, incremental dosing, epinephrine containing intravascular test dose

19. Basic local anesthetic dosing on body weight and body surface area는 minimal value fig.81-1

20. Lower extrmity pph. Block는 multiple , moderate volume individual n. block이 필요한경우가 많으므로 특히 systemic toxicity의 risk가 높다 • Large volume of local anesthetic는 pneumatic tourniquet를 통과할수 있으며,rapid, high pr. Inj.후에는 systemic circulation에 들어갈수있음- distal vein으로의 slow(90sec)inj.은 이러한 complication을 현저히 감소시킴 • Initial inj.후 약30분간은 tourniquest을 deflation시키지 않는것이좋다

21. Vascular injury - hematoma and bruising- eg. Axillary approach시 약 20%에서 bruising발생 - local anesthetic or needle induced vasospasm -> transarterial axillary block의 1%에서 발생 but, 10~15분이내에 resolve -> vasospasm지속시 intraarterial lidocaint, topical warming, NTG paste등을 사용 but, prolonged vascular vasospasm은 hematoma, arterial wall injury, dissection, pseudoaneurysm등에 의한 이차적인 direct arterial compression을 의미 * neurologic deterioration, hematoma expansion, unchanged neurologic exam. despite a resolving hematoma, documented vascular or lymphatic obstruction시 surgical exploration필요

22. Neurologic complications • 9개월이상 지속되는 permanent anesthesia related nerve injury(ARNI)는 매우 드물다(<0.02% to 0.4%) - popliteal fossa block의 경우를 제외 • GA.에 비해 regional A.는 medicolegal claim에 관련되는 경우가 많다 • Preexisting neuropathology 를 가진환자나 continuous axillary catheter techique는 neurologic injury risk를 증가시키지 않는다 • 대다수의 perioperative peripheral n. injuries는 6주이내에 resolve되며 약0.4%이하에서만 permanent sequelae를 남긴다( peripheral n. injury는 흔히 수술후 48~72hr이내에 나타나며, hematoma, postop. edema, intraoperative traction, trassection등에 의한 2차적인 injury는 즉시 나타나지만 reactive tissue, scarring등에 의한 2차적인 injury는 3주이상지연된다) - immediate consultation to help localize injury site, document preexisting occult or subclinical neurologic pathology, ensure appropriate rehabilitation prescription등이 추천 감별진단 –table 81-3

23. table 81-3

24. Category of the mechanism of pph. N. injury • Mechanical injury - the significance of paresthesia elicitation is most controversial -> some studies link injury to documented paresthesia within a particular nerve’s distribution, while others have been unable to link consistently paresthesia to subsequent injury - 실제 paresthesia의 definition은 다양하다 -> indirect pressure transmitted from perineural tissues, direct needle to nerve contat. or needle within the nerve • Consensus opinion은 paresthesia를 n. injury보다는 needle과 nerve가 충분히 근접했다는것을 알려주는 endpoint or warning sign으로 받아들이고 있다 • Needle bevel design의 role은 controversial -> nerve penetration은 sharp needle 보다 blunt needle이 덜하나 일단 penetration되면 damage는 후자가 더 심하고, nerve fiber에 parallel 하게 penetration되는것이 transverse penetration보다 회복이 더 빠른것으로 되어있다

25. fig.81.2

26. Chemical injury • All local anesthetics are potentially neurotoxic, decrease pph. Nerve blood(PNBF) -> lidocaine2% reduce PNBF by 40%, epi.첨가시 20%더 감소(동물실험), in human에서 well tolerated Prevention • Any specific regional anesthetic technique이 더 ARNI의 incidence가 높다는 증거는 없다. • pph. Nerve stimulator 사용이 intraneural injection or pph. Nerve injury를 보장하지는 않는다 • Initial inj.of local anesthetic near a nerve는 slowly, with very small volume으로

27. Pulmonary complications * Pneumothorax • Brachial plexus는 lung에 매우 근접(eg, Rt.side)하므로 매우 주의를 요하며 특히 supraclavicular approach과 관련 • 대개 symptom은 block시행후 6~12hr후에 나타나며 환자가 pleuritic chest pain or dyspnea호소시 즉시 chest radiograph확인 * Phrenic nerve paresis • Phrenic nerve(C3~5)는 brachial plexus와 밀접히 관련되며, above the clavicle approach시 hemidiaphragmatic paresis는 흔히 발생 Interscalene block 시 100%발생, 이때 pulmonary spirometeric values 가 37%가량 감소한다 • Reduded concentration of ropivacaine, digital pr. applied to the interscalene groove cephalad to the point of injection or smaller volume of local anesthetic do not reduce the occurrence of phrenic n. blockade • So, moderate to severe respiratory dis. 가진 환자에서의 above clavicle brachial plexus block는 상대적으로 금기이다 • Infraclavicular and axillary approach는 resp.function에 큰 영향이 없다

29. Unintended local anesthetic destinations • Vast network of neural structures of the neck -> ease exposure to local anesthetic solution originally intended for the brachial plexus -> subarachnoid, epidural spaces, spinal cord • 정상체형환자에서 vertebral column은 interscalene groove를 덮는 skin에서 약 4cm이내에 위치,특히 anesthetized or heavily sedated pt. 에서 subsequent intramedullary inj. and permanent spinal cord injury에 주의 • 그외 recurrent RLN(eg interscalene block시), cervical sympathetic nerve(-> Horner’s synd.야기) 도 주의

31. Hypotensive/bradycardic events • Interscalene block으로 shoulder surgery를 시행받는 awake, sitting pt.의 약 20%에서 Hypotensive/bradycardic events(HBE)가 발생할수 있다 • preop.vol. restriction, beach chair positon, exogenous epinephrine는 empty ventricle를 vigorous contract를 시킴 • Spinal anesthetic block시 약 block후 30~60분후에 잘 발생하며 beta blockade with metoprolol로 그 빈도를 감소시킬수 있다(glycopyrrolate는 효과가 없다)

32. Muscle injury • Infection - exogenous due to contaminated equipment or medication - endogenous secondary to a bact. Source - indwelling catheter는 inf. complicaiton risk를 증가시키지 않으며, 예방적 항생제 사용도 필요없다 Hollow viscus penetration - Lower extremity pph. Nerve block시 잘 발생