Interscalene posterior brachial plexus block


our experience with a peripheral stimulator




Maurizio Pintore, Vincenzo Galdo,Fernando Chiumiento Andrea Minichini,Alfonso D’Agostino






Department of Anaesthesia and Reanimation - Hospital "S. Francesco d’Assisi" OLIVETO CITRA (SA) , Italy

Chief physician: Dr. Giuseppe Visciani




Dr. Maurizio Pintore, Department of Anaesthesia and Reanimation - Hospital "S. Francesco d’Assisi"

P.zza Bergamo - 84025 Oliveto Citra (SA) , Italy tel. : +39.828 .797230 TEL/FAX 089/954285








The authors have used the technique of interscalene posterior brachial plexus block (according to P.Pippa), extended by using a peripheral stimulator; the following has been revealed:

Using the stimulator it can be confirmed that there is the possibility to enter into the space defined by the division of the layers of the prevertebral fascia, where the three trunks of the brachial plexus pass;

Possibility to block the high components of the brachial plexus for surgery or orthopedic treatments to reduce the 3° superior humerus of the shoulder, the collarbone;

Block of the brachial plexus in an anatomic part which is surrounded mainly by muscles and therefore, with respect to the lower interscalene parts, there is less possibility that complications occur (pneumothorax, total spinal, hemiparesis, phrenic nerve block, recurrent nerve block, inter-vascular injections, C.B. Horner syndrome;

Possibility to block the brachial plexus, without mobilizing the upper limb in case this is possible (traumas, fractures);


65 Patients have been exposed to a posterior brachial plexus block because operations of reduction or surgery of the 3° superior of the arm, of the shoulder of the collarbone where necessary; a peripheral stimulator and injections with xilocaina at 2% and bupivacaina at 0,5% with adrenalin 1:200.000 in equal volumes; maggior complications didn’t occur, there was just one case of intollerance to local anaesthesia; in case there was an insufficiency of the analgesia, pharmalogical support has been used in the form of fentanyl and propofol.


key words: brachial plexus, peripheral stimulator, prevertebral fascia, interscalene muscles, local anaesthesia.





The brachial plexus starts from the joining point of the anterior branches of the cervical inferior nerves c5-c6-c7-c8 and gives a considerable number of T1 components; the 4° cervical nerve and the 2° thoracic, send a ramuscle to the plexus. The branches of the plexus, are constituted laterally in three main trunks between the anterior and medium scalene muscles; of the inferior sides of the scalene muscle, the 3 trunks of the plexus with respect to the first rib are constituted of a superior, a medium and a inferior component to become at a lower point, with respect to the axillary artery, a lateral, medial and posterior component.

From the intervertebral foramen at the arm onward, the plexus is contained in a closed space defined by the prevertebral space which at a higher point splits to wrap the anterior and medial muscles up in two layers to become inferiorly an axillary sheath at the hight of the homonymus cable.

The anatomical charateristics which have been mentioned above are the preconditions to apply the technique of plexus identification, which is based through the posterior approach, on three particular evidences:

) Perception of the click of the posterior layer of the prevertebral fascia when passing the needle;

2) Loss of resistance, with the air mandril technique in the syringe (loss of resistance test), when the interscalene sheath is entered;

3) Sollecitation with the peripheral stimulator of the components of the plexus and obviousness of synchrone and/or paresthetic muscular contractions.


Materials and methods


65 Patients, of which 41 men and 24 women aged between 18 and 76 years, placed in the ASA classification between 1 and 3;

the charateristics of the patients and the concomitant pathologies are given in table 1.

The analgesia has been applied because of surgical needs and/or treatments of orthopedic reductions of the superior limb above the forearm: elbow fracture, of the shoulder, collarbone, traumatic lesions of the long head of the biceps, surgery of usual dislocation of the shoulder, diagnostical atroscopy and/or operational atroscopy of the shoulder.

The patients have been premedicated about 30 min. before the treatment, with 0,5-1mg of atropina and 7-10 mg of intramuscular diazepam; the basilic vein or the cephalic free limb has been injected with a cannula needle 18-20G. the monitoring by grafical ECG, P.A. and SAO2 was carried out.

The blocks have been carried out 30 min. before the treatment; volumes of 40 ml. local aneasthesia for surgical treatments, and of 30 ml for treatments to reduce and/or stabilize dislocations and fractures.

To carry out a posterior brachial plexus, we have used the reference points and the technique set up by Pippa, adding the garanty obtained by the use of the peripherical stimulator. We have used needles with a round end (sheath click) 0,8x100mm 21G (STIMUPLEX KANULE A- B.BRAUN) and peripheral stimulator (STIMUPLEX B.BRAUN).

The reference point where the needle must be entered is situated between 3 and 5 cm’s, laterally at the point in the middle between the cutaneous projections of the spinous apophysis of the 6° and 7° cervical vertebral; the patient is kept in a sitting position with the head slightly bended foreward , and blister anaesthesia is carried out. the needle is injected in a perpendicular way in the cutis, and is slowly entered in the different muscular layers (trapezius muscle, splenius and the elevator of the shoulder blade), keeping a syringe of 5 ml full with air, in continuous compression coupled to the lateral joint of the needle; the patient is asked to put his head to the counter-lateral shoulder in order to remove the two tansverse apophysis and in this way putting into tension the two layers of the prevertebral fascia; immediately after the perception of the sheath click can be noticed that the interscalene space has been entered, by the loss of resistance of the syringe full of air (loss-of-resistance-test); at this point the use of the stimulator, which has been prepared before and attached to indifferent electrodes, will cause synchronous muscular contractions (brachial plexus dependences) and/or parasthesias that give the confirmation of the correct positioning of the anaesthetical injection, proceeded by inhalation. We used a volume in equal parts of 40 ml of bupivacaina 0,5% dose and xilocaina 2% dose with the addition of adrenalin 1:200.000; such a volume a necesssary to involve in the bloc also the ulnar nerve and the cutaneous medial nerve of the arm.







With the posterior brachial plexus block we obtained good results with surgical treatment and/or treatments of orthopedical reduction of the shoulder and of the 3° superior of the arm, especially with patients who demonstrate concomitant systemic pathology for which general anaesthesia could creat potential problems (B.O.C.: emphysema; diabetes; hepatical pathologies; insufficient functioning of the kidneys). A volume of 40 ml has been necessary to garanty the analgesia also in territories that depend on the ulnar and medial cutaneous nerve of the arm. The results of the block have been classified as follows:

1. Complete =excellent analgesia, tranquillity and reassurance of the patient until the end of the treatment)

2. Incomplete =non perfect analgesia, that left some places of the plexus uncovered, the patient is complaining of bother and/or pain

(necessity of endovein analgesia and soothing)

3. Faillure =necessity of general analgesia


Table 2 gives the case-histories with the used dosages and the results.

Apart from one case of intollerance to local anesthesia , we didn’t find maggior complications which occur more often with lower interscalene blocks (nearness of other important anatomic components).

The percentage of failures of the blocks is inversely proportional to the experience of the operating surgeon, without excluding the existence of anatomic variations that are interfering to the technique



Globally we think that for surgery of the superior limb, putting on a scale efficiency and potential risks, the axillary brachial plexus block is the best and most profitable solution for treatments underneath the elbow. For treatments above the elbow the most profitable solution is the posterior interscalene block (according to Pippa). The latter block, apart from the advantages that we already mentioned, makes it possible to apply a technique with superior vein and motionless neck, which is a vital prerequisite for orthopedic surgery regarding traumas.




Tabella 1: Main characteristics



Patients 65

Men 41

Women 24

Age 18-76 years

Weight 65-95 kg

A.S.A. 1-3

Concomitant pathologies

Corpulent 11 patients

Diabetes 3 patients

B.O.C. 8 patients

Hepatopathies 7 patients

Hypertension 5 patients



Tabella 2:results


Type of surgery N° pts. , Dose (ml), Complete, Incomplete* ,Faillure §

Normal dislocation 26, 40, 16, 7, 3

of the shoulder



Artroscopy shoulder

(diagnosis+ operation) 10, 35 ,7, 3, 0


Ostesynthesis Fractures 9, 40, 5, 3 ,1

humerus head


Diaphysis Fractures 8, 40 ,4 ,2, 2



Fracture of the long 5, 40 ,5, 0, 0

head of the biceps



Reduction of shoulder

dislocation 7 ,30 ,7, 0, 0


Latency to initiate the treatment 25-35 min.

*Necessity analgesia and soothing (fentanyl 0,1mg+propofol 2-3mg/kg/h)

§Necessity general anaesthesia





1)P.Pippa,E .Cominelli,C.Marinelli, and S.Aito

Brachial plexus block using the posterior approach.

European Journal of Anaest.1990;7:411-420.

2)Winnie AP.Interscalene brachial plexus block.


3)Ward M.E.:The interscalene approach to the brachial plexus.

Anaestesia 29:147,1974

4)Winnie,A.P., et al.:Interscalene cervical plexus block.

Anesth. Analg.(Cleve),54:370,1975.

5)Wen-Hsien,W.U.:Brachial Plexus Block.J.A.M.A.,


6)Hopcroft,S.C.:The axilary approach to the brachial plexus anaestesia.Anaesthia Intensive Care,1:232,1973.



The undersigning Authors declare that the research being the basis of this study has been carried out in accordance with the Declaration of Helsinki and/or the international Principles that regolate the research on animals.