ANESTHESIA ANDANALGESIA . . . Current Researches VOL.54,NO. 3, MAY-JUNE, 1975
370
Interscalene Cervical Plexus Block: A Single-Injection Technic A. P. WINNIE, M . D . * t S. RAMAMURTHY, M.D. Z. DURRANI, M.D. R. RADONJIC, M.D. Chicago, lllinoist
A review of the anatomy of the cervical plexus and surrounding structures suggests a singleinjection technic which simplifies anesthesia of the cervical plexus and increases the margin of
safety in this procedure. Used by the authors, the technic has been successful in 97 percent
N
However, most procedures described over the years following Heidenhein’s original description have consisted of minor modifications of the position of the “primary line” connecting the tip of the mastoid process and the anterior tubercle of the 6th cervical vertebra, in order to place this line more precisely over the tips of the cervical transverse processes. The very fact that the position of this line varied from technic to technic while the underlying anatomy obviously remained constant indicates the lack of accuracy provided by these topographic landmarks. And in addition to the inaccuracy of these technics, all are complex, requiring multiple injections and relatively large volumes of anesthetic. Furthermore, with most technics, following the three injections at the transverse processes, an additional injection was made along the posterior margin of the sternocleidomastoid muscle to block the superficial cervical plexus as it emerges from under cover of that muscle, apparently just in case blockade of the deep cervical plexus was incomplete.
would dispute the truism that regional anesthesia is nothing more than applied anatomy. Yet the more one examines the current technics of regional anesthesia, the more one is impressed with the degree to which anatomy has been ignored. Nowhere is this more true than in the complex technics for anesthesia of the cervical plexus. If regional anesthesia is nothing more than applied anatomy, a study of the pertinent anatomy indicates that identical anesthesia can be obtained using a much simpler, safer, single-injection technic. OBODY
Historic Background .-Two approaches to cervical plexus anesthesia were available (fig. 1) to the early proponents of conduction anesthesia, the posterior approach of Kappisl and the lateral approach of Heidenheh2 The posterior approach has never gained widespread acceptance except as an alternative to the lateral, which has formed the basis for virtually all subsequent technics.
of over 100 cases.
*Professor and Head, Department of Anesthesiology, Abraham Lincoln School of Medicine. ?Departments of Anesthesiology, Abraham Lincoln School of Medicine, University of Illinois at the Medical Center, University of Illinois Hospital, and West Side Veterans Administration Hospital, Chicago, Illinois 60612. Read at the 49th Congress of the International Anesthesia Research Society, March 16-20, 1975, Hollywood, Florida. Paper received: 2/3/75 Accepted for publication: 2/20/75
Cervical Plexus Block
37 1
. . . Winnie, et a1
FIG.1. “Deep cervical block’ by the original posterior (Kappis) and lateral (Heidenhein) routes. Using the posterior approach, the needles are inserted 3 cm. from the midline ( A ) and advanced until the articular pillar is contacted, whereupon the needles are withdrawn and reinserted more laterally until they ”walk off’ the lateral margin of the transverse processes. at which point the local anesthetic is injected. Using the lateral approach, a line is drawn from the mastoid process above to the transverse process of C-6 below, indicating the location of the cervical transverse processes. Then using either two or three needles ( B ) . the lateral margins of the 2d, 3d, and 4th cervical transverse processes are contacted, whereupon the anesthetic solution is injected. (From T h e Management of Pain. with permission of publisher and author.)
Ant scalene rn
Cervical nlerscalene
f
Slernomosloa m
Longus captlfs rn
Longus colli m
Past primary divisian of C4
FIG 2. After leaving the intervertebral foramina, the anterior primary r a n i of the cervical nerves pass laterally behind the vertebral artery and vein in the gutter formed by the anterior and posterior tubercles of the corresponding transverse processes of the cervical vertebrae. In this short course, each ramus actually lies in a short fibrous tunnel formed by the transverse processes superiorly and inferiorly and bv the anterior and posterior intertransversarii muscles (not shown here) which extend between the anterior and posterior tubercles respectively of the transverse processes of the contiguous cervical vertebrae. Note that the posterior primary division leaves the anterior division just before the latter passes between the two tubercles, so injected anesthetic solutions must move centrad into this tunnel in order to block the posterior division.
Anatomic Considerations.-Although the cervical plexus is formed by the upper 4 cervical nerves, the regional anesthetist need consider only the 2d, 3d, and 4th cervical nerves, since the 1st cervical nerve is almost exclusively composed of motor fibers, and only rarely has any significant sensory component. After leaving the intervertebral foramina, the anterior primary rami of the 2d, 3d, and 4th cervical nerves pass laterally behind the vertebral artery and vein in the gutter formed by the anterior and posterior tubercles of the corresponding transverse processes of the cervical vertebrae (fig. 2 ) . As the nerve aproaches the lateral extremity of the transverse process, it flattens and passes closer to the posterior than to the anterior tubercle, and the posterior primary division leaves the anterior division just before the latter passes between the two tubercles. After leaving the transverse processes, the roots of the plexus enter a perineural space formed by the muscles and tendons attached to the anterior and posterior tubercles of the 2d, 3d, and 4th cervical vertebrae, that is, by the scalenus anterior muscle anteriorly and the scalenus medius posteriorly. Thus, as the prevertebral fascia moves
ANESTHESIA AND ANALGESIA. . . Current Researches VOL.54, No. 3, MAY-JUNE. 1975
372
FIG.3. The formation of the cervical plexus: The anterior primary rami of the 2d, 3d, and 4th cervical nerves divide into ascending and descending branches, forming a series of three loops, each of which gives rise to a superficial and deep branch. The deep branches (heavy lines) provide the motor innervation of most of the neck muscles, while the superficial branches constitute what is known as the superficial cervical plexus, which provides all the cutaneous innervation of the back of the head, the neck, and the shoulders (insert). The cranial nerves are depicted as striped, and the gray rami from the superior cervical symDathetic eanelion to the 1st cervical nerves as dashed lines. (From The Anatomical Basis of Medical Practice, with permission of the publisher; insert from The Management of Pain, with permission of publisher and author.)
- -
laterally and splits to invest these muscles all of the cutaneous innervation of the back and their tendons, it forms a closed fascia1 of the head, neck, and shoulders (insert, compartment which is really just an exten- fig. 3). All these superficial branches pierce sion superiorly of the interscalene space. the deep cervical fascia and emerge at the After entering this space, the roots of the middle of the posterior border of the stercervical plexus rearrange themselves as fol- nocleidomastoid muscle, from which point lows (fig. 3) : The anterior primary rami of they diverge to take their separate cutanethe 2d, 3d, and 4th cervical nerves divide ous courses. into ascending and descending branches, Clinical Considerations.-The preverteforming a series of three loops. Each of these three loops gives rise to a superficial bra1 fascia invests all the prevertebral musand deep branch: the deep branches of the cles, the longus colli, the longus capitis, and cervical plexus provide the motor innerva- the scalenus anterior muscle. Superiorly, tion of most of the neck, while the superfi- this important layer of fascia is attached to cial branches constitute what is known as the base of the skull, from which it extends the superficial cervical plexus and provide down over the longus colli to the level of the
Cervical Plexus Block
. . . Winnie. et a1
3d thoracic vertebra, where it fuses with the anterior longitudinal ligament and the periosteum of the vertebral bodies. Laterally, at the tips of the cervical transverse processes, it is also continuous with the fascia of the upper part of the floor of the posterior cervical triangle; thus it invests the scalenus medius, the levator scapulae, and the splenius capitis muscles. Therefore, it becomes apparent that the fascia investing the muscles and tendons lying anterior and posterior to the cervical plexus provides a fascia1 envelope around the plexus, which can serve as a perineural sheath, and provides the basis for an extremely simple technic for performing a cervical plexus block. The Single-Znjection Technic.-The patient is in the dorsal recumbent position with the head turned slightly to the side opposite that to be blocked. The patient is asked to lift his head off the table, a maneuver which brings the sternocleidomastoid muscle into prominence. The index and middle fingers of the anesthetist's hand are placed posterior to the patient's tensed sternocleidomastoid muscle at the level of C-4, which is determined by noting the level of the superior margin of the thyroid cartilage, and the patient is then asked to relax. The palpating fingers of the anesthetist now lie on the anterior surface of the belly of the scalenus anterior muscle (fig. 4). From this point, the fingers are rolled laterally across
373
i FIG.5. The technic of interscalene cervical plexus block: Step 2. The anesthetist now carefully rolls his fingers laterally until the groove between the anterior and middle scalene muscles is palpated. By utilizing two fingers for palpation, digital pressure indents the skin and decreases the distance between the skin and cervical transverse processes.
FIG.6. The technic of interscalene cervical plexus block: Step 3. A n immobile needle is inserted a t the level of C-4 between the palpating fingers a s the latter depress the skin over the interscalene groove. The needle is advanced in a direction perpendicular to the skin in all planes, that is, the direction is mostly mesiad but slightly dorsad and caudad. The caudal direction is critical to the safety of the technic since the advancing needle, properly directed, will encounter the next cervical transverse process if parasthesias are not obtained. A horizontal direction would allow a needle that has missed the cervical roots to enter the vertebral vessels or the epidural or subarachnoid spaces. FIG.4. T h e technic of interscalene cervical plexus block: Step 1. The patient is supine, with his head turned slightly to the side opposite that about to be blocked. The level of C-4 is determined by noting the level of the upper margin of the thyroid cartilage. While the patient elevates his head to bring the sternocleidomastoid muscle into prominence, the anesthetist places the index and middle fingers behind (posterior to) the latter muscle a t the level of C-4, and the patient is asked to relax. The palpating fingers now lie upon the anterior surface of the belly of the anterior scalene muscle.
the belly of this muscle until the groove between the scalenus anterior and scalenus medius muscles is palpated (fig. 5 ) . An immobile needle3 is inserted between the palpating Gngers (fig. 6) in a direction that is mostly mesiad, but also slightly caudad and slightly dorsad, the needle being perpendicular to the skin of the neck in every plane. The needle is advanced until
374
ANESTHESIA AND ANALGESIA. . . Current Researches VOL.54, No. 3, MAY-JUNE, 1975
a paresthesia is elicited and/or the transverse process of C-4 is encountered; once a paresthesia has been evoked, 10 to 15 ml. of anesthetic solution is injected. As with the interscalene technic of brachial plexus block, it is critical that the needle have a slightly caudad direction, so that if a nerve is not encountered on the first needle insertion, the needle will be stopped by the transverse process of C-5. If the needle is placed in a more horizontal direction, deep insertion of the needle is not prevented, and injection into the vertebral artery, epidural space, or subarachnoid space becomes possible. The properly placed needle lies in the fascia-enclosed space described earlier, so the solution injected will ascend and descend within this space to block all roots of the cervical plexus and part or all of the brachial plexus, depending on the volume injected.
FIG.7. The technic of interscalene cervical plexus block: Step 4 . When a paresthesia (of the appropriate nerve distribution) has been obtained, the needle is immobilized and the anesthetic solution is injected. Digital pressure just inferior to the needle during the injection will limit the spread of the local anesthetic to the cervical interscalene space and thus minimize the volume of solution necessary to produce anesthesia of the cervical plexus.
Figure 7 represents this schematically and figure 8 documents roentgenographically the spread within the interscalene space of an anesthetic solution injected through a properly placed needle, utilizing an anesthetic solution to which a radiopaque dye has been added. If it is desirable to reduce the volume necessary to provide cervical plexus anesthesia and/or if anesthesia of the brachial plexus is unnecessary or undesirable, digital pressure just below the injection prevents caudad spread and allows adequate cervical plexus anesthesia to be provided with as little as 10 ml. of anesthetic.
DISCUSSION In extensive successful experience with the perivascular technics of brachial plexus anesthesia, it was observed repeatedly that, regardless of which of the perivascular technics was used, if a sufficient volume of anesthetic is injected, anesthesia of the cervical plexus results.4.5 Hence it became apparent that since the cervical plexus, like the brachial plexus, lies in the space between the anterior and middle scalene muscles, it can be blocked with a single injection carefully placed between these muscles at a higher level. Obviously, since the injection in the described technic is made within a space that is continuous with the interscalene, subclavian, and axillary perivascular compartments, anesthesia of the cervical plexus can also be provided, if necessary, by injections of appropriate volumes into these spaces,
FIG.8. The technic of interscalene cervical plexus block: Step 5. If digital pressure is not applied inferior to the needle, the injected solution is free to spread down to the subclavian and axillary perivascular spaces. This is demonstrated here by taking an x-ray immediately following an injection of 30 ml. of local anesthetic solution to which radiopaque dye has been added.
as long as the volume injected is increased in proportion to the increase in the distance of the site of injection from the superior portion of the interscalene space. In other words, anesthesia of the cervical plexus can be provided by 60 ml. injected into the axillary perivascular space, 40 ml.
Cervical Plexus Block.
. . Winnie, et a1
375 gins of c-2, c-3, and c-4 spreads mesiad far enough to block the posterior primary divisions of the respective nerves, Bonica injected 5 ml. of radiopaque dye through the middle needle. X-rays taken shortly after this injection document the desired spread of the solution medially (fig. 9 ) , but more significantly, also demonstrate that even using this small volume, an injection properly placed in the interscalene space moves up and down within this space to bathe all three nerves of the plexus, rendering additional injections superfluous.
FIG.9. Roentgenogram taken 5 sec. after 5 ml. of 35 percent contrast medium was injected through the middle needle of three needles placed according to the traditional lateral technic. While intended to demonstrate the mesiad spread of the solution, the film demonstrates the spread of the solution cephalad and caudad to surround the tips of all three of the properly placed needles. (From T h e Management of Pain, with permission of publisher and author.)
injected into the subclavian perivascular space, 20 ml. injected into the brachial (inferior) half of the inteiscalene space, or 10 ml. injected into the cervical (or superior) half of the interscalene space. Thus, interscalene cervical plexus block has the same relationship to the perivascular concept as cervical epidural block has to the peridural concept. New developments are frequently based on rediscovery of old, forgotten information. Such is certainly the case with the interscalene technic of cervical plexus block. In his monumental classic, The Management of Pain,G Bonica, perhaps inadvertently, demonstrated the principles upon which the present technic is based: In attempting to demonstrate roentgenographically that anesthetic solution injected through three needles properly placed at the lateral mar-
CONCLUSIONS We have used the technic of interscalene cervical plexus block in well over 100 patients for surgical anesthesia in the operating room, and for diagnostic and therapeutic purposes in our Pain Clinic. Excellent anesthesia resulted in all patients except three, in whom metastatic disease or previous surgical operations prevented the uniform spread of the anesthetic solution. In these cases, anesthesia was extended by simply repeating the block, using an identical technic but at the level unanesthetized by the first injection. REFERENCES 1. Kappis H: Wber Leitunganasthesie am Bauch,
Brust, Arm, und Hals durch Injection ans Foramen intervertebrale. Munchen Med Wschr 59: 794-796, 1912 2. Heidenhein L: Operations on the neck, Local Anesthesia (translation of 3rd edition by P Shields), by H Braun. Philadelphia, Lea & Febiger, 1914, pp 268-269 3. Winnie AP: An immobile needle for nerve blocks. Anesthesiology 31:577-578, 1969 4. Winnie AP, Collins V J : The subclavian perivascular technique of brachial plexus anesthesia. Anesthesiology 25:353-363, 1964
5. Winnie AP: Interscalene brachial plexus block. Anesth & Analg 49:455-466, 1970 6. Bonica JJ: Blocking the somatic spinal nerves. The Management of Pain. Philadelphia, Lea & Febiger, 1953, p 292
370
Interscalene Cervical Plexus Block: A Single-Injection Technic A. P. WINNIE, M . D . * t S. RAMAMURTHY, M.D. Z. DURRANI, M.D. R. RADONJIC, M.D. Chicago, lllinoist
A review of the anatomy of the cervical plexus and surrounding structures suggests a singleinjection technic which simplifies anesthesia of the cervical plexus and increases the margin of
safety in this procedure. Used by the authors, the technic has been successful in 97 percent
N
However, most procedures described over the years following Heidenhein’s original description have consisted of minor modifications of the position of the “primary line” connecting the tip of the mastoid process and the anterior tubercle of the 6th cervical vertebra, in order to place this line more precisely over the tips of the cervical transverse processes. The very fact that the position of this line varied from technic to technic while the underlying anatomy obviously remained constant indicates the lack of accuracy provided by these topographic landmarks. And in addition to the inaccuracy of these technics, all are complex, requiring multiple injections and relatively large volumes of anesthetic. Furthermore, with most technics, following the three injections at the transverse processes, an additional injection was made along the posterior margin of the sternocleidomastoid muscle to block the superficial cervical plexus as it emerges from under cover of that muscle, apparently just in case blockade of the deep cervical plexus was incomplete.
would dispute the truism that regional anesthesia is nothing more than applied anatomy. Yet the more one examines the current technics of regional anesthesia, the more one is impressed with the degree to which anatomy has been ignored. Nowhere is this more true than in the complex technics for anesthesia of the cervical plexus. If regional anesthesia is nothing more than applied anatomy, a study of the pertinent anatomy indicates that identical anesthesia can be obtained using a much simpler, safer, single-injection technic. OBODY
Historic Background .-Two approaches to cervical plexus anesthesia were available (fig. 1) to the early proponents of conduction anesthesia, the posterior approach of Kappisl and the lateral approach of Heidenheh2 The posterior approach has never gained widespread acceptance except as an alternative to the lateral, which has formed the basis for virtually all subsequent technics.
of over 100 cases.
*Professor and Head, Department of Anesthesiology, Abraham Lincoln School of Medicine. ?Departments of Anesthesiology, Abraham Lincoln School of Medicine, University of Illinois at the Medical Center, University of Illinois Hospital, and West Side Veterans Administration Hospital, Chicago, Illinois 60612. Read at the 49th Congress of the International Anesthesia Research Society, March 16-20, 1975, Hollywood, Florida. Paper received: 2/3/75 Accepted for publication: 2/20/75
Cervical Plexus Block
37 1
. . . Winnie, et a1
FIG.1. “Deep cervical block’ by the original posterior (Kappis) and lateral (Heidenhein) routes. Using the posterior approach, the needles are inserted 3 cm. from the midline ( A ) and advanced until the articular pillar is contacted, whereupon the needles are withdrawn and reinserted more laterally until they ”walk off’ the lateral margin of the transverse processes. at which point the local anesthetic is injected. Using the lateral approach, a line is drawn from the mastoid process above to the transverse process of C-6 below, indicating the location of the cervical transverse processes. Then using either two or three needles ( B ) . the lateral margins of the 2d, 3d, and 4th cervical transverse processes are contacted, whereupon the anesthetic solution is injected. (From T h e Management of Pain. with permission of publisher and author.)
Ant scalene rn
Cervical nlerscalene
f
Slernomosloa m
Longus captlfs rn
Longus colli m
Past primary divisian of C4
FIG 2. After leaving the intervertebral foramina, the anterior primary r a n i of the cervical nerves pass laterally behind the vertebral artery and vein in the gutter formed by the anterior and posterior tubercles of the corresponding transverse processes of the cervical vertebrae. In this short course, each ramus actually lies in a short fibrous tunnel formed by the transverse processes superiorly and inferiorly and bv the anterior and posterior intertransversarii muscles (not shown here) which extend between the anterior and posterior tubercles respectively of the transverse processes of the contiguous cervical vertebrae. Note that the posterior primary division leaves the anterior division just before the latter passes between the two tubercles, so injected anesthetic solutions must move centrad into this tunnel in order to block the posterior division.
Anatomic Considerations.-Although the cervical plexus is formed by the upper 4 cervical nerves, the regional anesthetist need consider only the 2d, 3d, and 4th cervical nerves, since the 1st cervical nerve is almost exclusively composed of motor fibers, and only rarely has any significant sensory component. After leaving the intervertebral foramina, the anterior primary rami of the 2d, 3d, and 4th cervical nerves pass laterally behind the vertebral artery and vein in the gutter formed by the anterior and posterior tubercles of the corresponding transverse processes of the cervical vertebrae (fig. 2 ) . As the nerve aproaches the lateral extremity of the transverse process, it flattens and passes closer to the posterior than to the anterior tubercle, and the posterior primary division leaves the anterior division just before the latter passes between the two tubercles. After leaving the transverse processes, the roots of the plexus enter a perineural space formed by the muscles and tendons attached to the anterior and posterior tubercles of the 2d, 3d, and 4th cervical vertebrae, that is, by the scalenus anterior muscle anteriorly and the scalenus medius posteriorly. Thus, as the prevertebral fascia moves
ANESTHESIA AND ANALGESIA. . . Current Researches VOL.54, No. 3, MAY-JUNE. 1975
372
FIG.3. The formation of the cervical plexus: The anterior primary rami of the 2d, 3d, and 4th cervical nerves divide into ascending and descending branches, forming a series of three loops, each of which gives rise to a superficial and deep branch. The deep branches (heavy lines) provide the motor innervation of most of the neck muscles, while the superficial branches constitute what is known as the superficial cervical plexus, which provides all the cutaneous innervation of the back of the head, the neck, and the shoulders (insert). The cranial nerves are depicted as striped, and the gray rami from the superior cervical symDathetic eanelion to the 1st cervical nerves as dashed lines. (From The Anatomical Basis of Medical Practice, with permission of the publisher; insert from The Management of Pain, with permission of publisher and author.)
- -
laterally and splits to invest these muscles all of the cutaneous innervation of the back and their tendons, it forms a closed fascia1 of the head, neck, and shoulders (insert, compartment which is really just an exten- fig. 3). All these superficial branches pierce sion superiorly of the interscalene space. the deep cervical fascia and emerge at the After entering this space, the roots of the middle of the posterior border of the stercervical plexus rearrange themselves as fol- nocleidomastoid muscle, from which point lows (fig. 3) : The anterior primary rami of they diverge to take their separate cutanethe 2d, 3d, and 4th cervical nerves divide ous courses. into ascending and descending branches, Clinical Considerations.-The preverteforming a series of three loops. Each of these three loops gives rise to a superficial bra1 fascia invests all the prevertebral musand deep branch: the deep branches of the cles, the longus colli, the longus capitis, and cervical plexus provide the motor innerva- the scalenus anterior muscle. Superiorly, tion of most of the neck, while the superfi- this important layer of fascia is attached to cial branches constitute what is known as the base of the skull, from which it extends the superficial cervical plexus and provide down over the longus colli to the level of the
Cervical Plexus Block
. . . Winnie. et a1
3d thoracic vertebra, where it fuses with the anterior longitudinal ligament and the periosteum of the vertebral bodies. Laterally, at the tips of the cervical transverse processes, it is also continuous with the fascia of the upper part of the floor of the posterior cervical triangle; thus it invests the scalenus medius, the levator scapulae, and the splenius capitis muscles. Therefore, it becomes apparent that the fascia investing the muscles and tendons lying anterior and posterior to the cervical plexus provides a fascia1 envelope around the plexus, which can serve as a perineural sheath, and provides the basis for an extremely simple technic for performing a cervical plexus block. The Single-Znjection Technic.-The patient is in the dorsal recumbent position with the head turned slightly to the side opposite that to be blocked. The patient is asked to lift his head off the table, a maneuver which brings the sternocleidomastoid muscle into prominence. The index and middle fingers of the anesthetist's hand are placed posterior to the patient's tensed sternocleidomastoid muscle at the level of C-4, which is determined by noting the level of the superior margin of the thyroid cartilage, and the patient is then asked to relax. The palpating fingers of the anesthetist now lie on the anterior surface of the belly of the scalenus anterior muscle (fig. 4). From this point, the fingers are rolled laterally across
373
i FIG.5. The technic of interscalene cervical plexus block: Step 2. The anesthetist now carefully rolls his fingers laterally until the groove between the anterior and middle scalene muscles is palpated. By utilizing two fingers for palpation, digital pressure indents the skin and decreases the distance between the skin and cervical transverse processes.
FIG.6. The technic of interscalene cervical plexus block: Step 3. A n immobile needle is inserted a t the level of C-4 between the palpating fingers a s the latter depress the skin over the interscalene groove. The needle is advanced in a direction perpendicular to the skin in all planes, that is, the direction is mostly mesiad but slightly dorsad and caudad. The caudal direction is critical to the safety of the technic since the advancing needle, properly directed, will encounter the next cervical transverse process if parasthesias are not obtained. A horizontal direction would allow a needle that has missed the cervical roots to enter the vertebral vessels or the epidural or subarachnoid spaces. FIG.4. T h e technic of interscalene cervical plexus block: Step 1. The patient is supine, with his head turned slightly to the side opposite that about to be blocked. The level of C-4 is determined by noting the level of the upper margin of the thyroid cartilage. While the patient elevates his head to bring the sternocleidomastoid muscle into prominence, the anesthetist places the index and middle fingers behind (posterior to) the latter muscle a t the level of C-4, and the patient is asked to relax. The palpating fingers now lie upon the anterior surface of the belly of the anterior scalene muscle.
the belly of this muscle until the groove between the scalenus anterior and scalenus medius muscles is palpated (fig. 5 ) . An immobile needle3 is inserted between the palpating Gngers (fig. 6) in a direction that is mostly mesiad, but also slightly caudad and slightly dorsad, the needle being perpendicular to the skin of the neck in every plane. The needle is advanced until
374
ANESTHESIA AND ANALGESIA. . . Current Researches VOL.54, No. 3, MAY-JUNE, 1975
a paresthesia is elicited and/or the transverse process of C-4 is encountered; once a paresthesia has been evoked, 10 to 15 ml. of anesthetic solution is injected. As with the interscalene technic of brachial plexus block, it is critical that the needle have a slightly caudad direction, so that if a nerve is not encountered on the first needle insertion, the needle will be stopped by the transverse process of C-5. If the needle is placed in a more horizontal direction, deep insertion of the needle is not prevented, and injection into the vertebral artery, epidural space, or subarachnoid space becomes possible. The properly placed needle lies in the fascia-enclosed space described earlier, so the solution injected will ascend and descend within this space to block all roots of the cervical plexus and part or all of the brachial plexus, depending on the volume injected.
FIG.7. The technic of interscalene cervical plexus block: Step 4 . When a paresthesia (of the appropriate nerve distribution) has been obtained, the needle is immobilized and the anesthetic solution is injected. Digital pressure just inferior to the needle during the injection will limit the spread of the local anesthetic to the cervical interscalene space and thus minimize the volume of solution necessary to produce anesthesia of the cervical plexus.
Figure 7 represents this schematically and figure 8 documents roentgenographically the spread within the interscalene space of an anesthetic solution injected through a properly placed needle, utilizing an anesthetic solution to which a radiopaque dye has been added. If it is desirable to reduce the volume necessary to provide cervical plexus anesthesia and/or if anesthesia of the brachial plexus is unnecessary or undesirable, digital pressure just below the injection prevents caudad spread and allows adequate cervical plexus anesthesia to be provided with as little as 10 ml. of anesthetic.
DISCUSSION In extensive successful experience with the perivascular technics of brachial plexus anesthesia, it was observed repeatedly that, regardless of which of the perivascular technics was used, if a sufficient volume of anesthetic is injected, anesthesia of the cervical plexus results.4.5 Hence it became apparent that since the cervical plexus, like the brachial plexus, lies in the space between the anterior and middle scalene muscles, it can be blocked with a single injection carefully placed between these muscles at a higher level. Obviously, since the injection in the described technic is made within a space that is continuous with the interscalene, subclavian, and axillary perivascular compartments, anesthesia of the cervical plexus can also be provided, if necessary, by injections of appropriate volumes into these spaces,
FIG.8. The technic of interscalene cervical plexus block: Step 5. If digital pressure is not applied inferior to the needle, the injected solution is free to spread down to the subclavian and axillary perivascular spaces. This is demonstrated here by taking an x-ray immediately following an injection of 30 ml. of local anesthetic solution to which radiopaque dye has been added.
as long as the volume injected is increased in proportion to the increase in the distance of the site of injection from the superior portion of the interscalene space. In other words, anesthesia of the cervical plexus can be provided by 60 ml. injected into the axillary perivascular space, 40 ml.
Cervical Plexus Block.
. . Winnie, et a1
375 gins of c-2, c-3, and c-4 spreads mesiad far enough to block the posterior primary divisions of the respective nerves, Bonica injected 5 ml. of radiopaque dye through the middle needle. X-rays taken shortly after this injection document the desired spread of the solution medially (fig. 9 ) , but more significantly, also demonstrate that even using this small volume, an injection properly placed in the interscalene space moves up and down within this space to bathe all three nerves of the plexus, rendering additional injections superfluous.
FIG.9. Roentgenogram taken 5 sec. after 5 ml. of 35 percent contrast medium was injected through the middle needle of three needles placed according to the traditional lateral technic. While intended to demonstrate the mesiad spread of the solution, the film demonstrates the spread of the solution cephalad and caudad to surround the tips of all three of the properly placed needles. (From T h e Management of Pain, with permission of publisher and author.)
injected into the subclavian perivascular space, 20 ml. injected into the brachial (inferior) half of the inteiscalene space, or 10 ml. injected into the cervical (or superior) half of the interscalene space. Thus, interscalene cervical plexus block has the same relationship to the perivascular concept as cervical epidural block has to the peridural concept. New developments are frequently based on rediscovery of old, forgotten information. Such is certainly the case with the interscalene technic of cervical plexus block. In his monumental classic, The Management of Pain,G Bonica, perhaps inadvertently, demonstrated the principles upon which the present technic is based: In attempting to demonstrate roentgenographically that anesthetic solution injected through three needles properly placed at the lateral mar-
CONCLUSIONS We have used the technic of interscalene cervical plexus block in well over 100 patients for surgical anesthesia in the operating room, and for diagnostic and therapeutic purposes in our Pain Clinic. Excellent anesthesia resulted in all patients except three, in whom metastatic disease or previous surgical operations prevented the uniform spread of the anesthetic solution. In these cases, anesthesia was extended by simply repeating the block, using an identical technic but at the level unanesthetized by the first injection. REFERENCES 1. Kappis H: Wber Leitunganasthesie am Bauch,
Brust, Arm, und Hals durch Injection ans Foramen intervertebrale. Munchen Med Wschr 59: 794-796, 1912 2. Heidenhein L: Operations on the neck, Local Anesthesia (translation of 3rd edition by P Shields), by H Braun. Philadelphia, Lea & Febiger, 1914, pp 268-269 3. Winnie AP: An immobile needle for nerve blocks. Anesthesiology 31:577-578, 1969 4. Winnie AP, Collins V J : The subclavian perivascular technique of brachial plexus anesthesia. Anesthesiology 25:353-363, 1964
5. Winnie AP: Interscalene brachial plexus block. Anesth & Analg 49:455-466, 1970 6. Bonica JJ: Blocking the somatic spinal nerves. The Management of Pain. Philadelphia, Lea & Febiger, 1953, p 292
