Letters to the Editor
Anesthesia for Clavicular Fracture and Surgery Accepted for Publication: December 18, 2013. To the Editor: e read with great interest the inaugural section “Daring Discourse” by Tran et al1 regarding analgesia for clavicular fracture and surgery. We agree with the authors’ qualified endorsement of Dejerine’s description of dual innervation of the clavicle by both the cervical and brachial plexus.2 In our experience, the true measure of success for nerve blockade is efficacy for surgical anesthesia. To this end, we wish to report a recent case where surgical fixation of the clavicle was performed solely under combined superficial cervical plexus and supraclavicular brachial plexus blockade using a single-needle insertion. A 17-year-old male patient presented for open reduction and internal fixation of a displaced fracture of the left clavicle. With patient consent, ostensibly for a nerve block for postoperative analgesia, an ultrasoundguided superficial cervical plexus block was first performed with a 22-gauge, 50-mm insulated needle using an in-plane technique. Fifteen milliliters of 0.5% ropivacaine and 0.125% bupivacaine [1:1] was injected deep to the prevertebral fascia between the sternocleidomastoid muscle and the anterior scalene muscle where the superficial cervical plexus traverses. The needle was then simply advanced to a location adjacent to the brachial plexus at a low interscalene location. Five milliliters of the same solution was deposited at this location (Fig. 1). Within 10 minutes of block completion, the patient had lost temperature sensation from the mandibular angle to the C5
W
Regional Anesthesia and Pain Medicine • Volume 39, Number 3, May-June 2014
dermatome of the anterior chest wall. Contemporaneously, he developed a complete motor block of the upper limb. This was deemed satisfactory anesthesia for the surgical procedure and the patient subsequently consented to an awake procedure. Performed in the beach chair position, the procedure lasted for 105 minutes. The patient reported being comfortable throughout the surgery. Despite no clinical evidence of respiratory distress, this combination of nerve blocks will undoubtedly lead to phrenic nerve blockade. We agree with Tran et al’s call for further clarification of the sensory innervation of the clavicle. A successful practice in ultrasound-guided regional anesthesia is based on a solid understanding of conventional anatomy. Occasionally, sonoanatomy may reciprocate and contribute to our existing knowledge.
Derek Dillane, FCARCSI Timur Ozelsel, MD, DESA Kristen Gadbois, FRCPC Department of Anesthesiology and Pain Medicine University of Alberta Edmonton, Alberta, Canada
The authors declare no conflict of interest. REFERENCES 1. Tran DQH, Tiyaprasertkul W, Gonzalez A. Analgesia for clavicular fracture and surgery: a call for evidence. Reg Anesth Pain Med. 2013;38:539–543. 2. Dejerine J. Syndromes sensitifs. Semeiologie des Affections du Systeme Nerveux. Paris, France: Masson; 1914.
FIGURE 1. Ultrasound scan of the left neck showing the subclavian artery (SA), brachial plexus (white circle), anterior scalene muscle (ASM), sternocleidomastoid muscle (SCM), and block needle (white line arrows). Spread of local anesthetic (LA) can be seen (left) deep to the prevertebral fascia (white solid arrows) where the superficial cervical plexus is found. The needle was then advanced to block the brachial plexus at a low interscalene location (right).
256
Adductor Canal Block or Midthigh Saphenous Nerve Block Same Same but Different Name! Accepted for Publication: October 23, 2013.
To the Editor: e read with great interest the study by Perlas et al,1 which, like our recent article,2 supports the idea that the addition of a saphenous nerve block to local infiltration analgesia improves the analgesia and early ambulation after total knee arthroplasty (TKA). Although we placed our injections in the adductor canal around the saphenous nerve, we chose not to use the term “adductor canal block.” This term is based on the theoretical assumption that a large volume of local anesthetic in the adductor canal would not only block the saphenous nerve but also other nerves that could be lying in the adductor canal. To our knowledge, no convincing studies have been published that clearly indicate that nerves other than the saphenous nerve are blocked by an injection of local anesthetic in the adductor canal. Perlas refers to the study by Horner and Dellon3 regarding nerves in the adductor canal (Hunter canal). This study, however, is not about the adductor canal; the authors are unclear about how the adductor canal is perceived and do not describe it. Thiel4 made an excellent anatomical atlas using dissection photoimages to visualize and describe the adductor canal and its contents. Only the saphenous nerve is described as lying in the adductor canal. The same applies to the study by Tubbs et al,5 which is also referenced by Perlas. What is called the adductor canal block is, in fact, equivalent to the midthigh saphenous nerve block. Other nerve branches may lie in close proximity to the canal but not in the canal at midthigh level and may not be affected by an injection in the adductor canal. The medial branch of the nerve to the vastus medialis muscle lies close to the adductor canal, but it is in the muscle or just under the muscle fascia at the midthigh level; this can be seen ultrasonographically. The anterior cutaneous branch of the obturator nerve is inconsistent and lies close to the adductor canal but not in the canal,4 and the posterior branch of the obturator nerve may pass through the adductor hiatus and could be blocked at this point on its way to the posterior knee capsule,6 but this is not shown in any study. These nerve branches may not play any
W
© 2014 American Society of Regional Anesthesia and Pain Medicine
Copyright © 2014 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this article is prohibited.
Regional Anesthesia and Pain Medicine • Volume 39, Number 3, May-June 2014
major role as pain-mediating nerves after TKA where the incision is made through the anterior knee capsule. The saphenous nerve innervates a major part of the anterior knee capsule and is, therefore, the main target for an ultrasound-guided nerve blockade after TKA. A large volume “to fill the adductor canal” may not be needed. Henning Lykke Andersen, MD Department of Anesthesiology Herlev University Hospital Copenhagen, Denmark
Dusanka Zaric, MD, PhD Department of Anesthesiology Frederiksberg University Hospital Copenhagen, Denmark
The authors declare no conflict of interest. REFERENCES 1. Perlas A, Kirkham KR, Billing R, et al. The impact of analgesic modality on early ambulation following total knee arthroplasty. Reg Anesth Pain Med. 2013;38:334–339. 2. Andersen HL, Gyrn J, Møller L, Christensen B, Zaric D. Continuous saphenous nerve block as supplement to single-dose local infiltration analgesia for postoperative pain management after total knee arthroplasty. Reg Anesth Pain Med. 2012;38:106–111. 3. Horner G, Dellon AL. Innervation of the human knee joint and implications for surgery. Clin Orthop Relat Res. 1994;301:221–226. 4. Thiel W. Adductor canal. In: Thiel W, ed. Photographic Atlas of Practical Anatomy I (Abdomen, Lower Limb): 1 vol. 1st ed. Berlin, Germany: Springer; 1997:228–235. 5. Tubbs RS, Loukas M, Shoja MM, Apaydin N, Oakes WJ, Salter EG. Anatomy and potential clinical significance of the vastoadductor membrane. Surg Radiol Anat. 2007; 29:569–573. 6. Kumka M. Critical sites of entrapment of the posterior division of the obturator nerve: anatomical considerations. J Can Chiropr Assoc. 2010;54:33–42.
authors that there are questions yet to be addressed regarding this analgesic intervention for an expanding range of surgical procedures. The most consistent neural target for subsartorial, midthigh injection is indeed the saphenous nerve. However, there is evidence that other peripheral nerves also travel in the adductor canal and provide additional innervation to the cutaneous, capsular, and articular aspects of the knee joint. Horner and Dellon3 explored the innervation of the knee joint. They refer to Hunter canal (an eponym equivalent to the adductor canal) to describe the aponeurotic space below the sartorius muscle and extending from the femoral triangle to the adductor hiatus. Horner and Dellon found that the canal consistently contained 1 or more infrapatellar branches of the saphenous nerve but also superficial branches from the medial cutaneous femoral nerve in 60.8% of cadavers. Similarly, they identified that the medial retinacular nerve (a terminal branch of the nerve to vastus medialis) penetrates the muscle bulk and provides innervation to the medial capsule of the joint. Although less consistently, they also observed the anterior branch of the obturator nerve entering the canal through the adductor magnus and contributing to perigenicular innervation in 11% of cadavers.3 We agree that the nerve to vastus medialis (a branch of the femoral nerve) can often be visualized on ultrasound. The bulk of this nerve lies within the adductor canal (deep to the vastoadductor membrane), although small muscular branches may be seen leaving the canal often accompanied by small arterial branches (Fig. 1). More distally, large terminal branches of this nerve cross the bulk of the muscle and provide innervation to deep articular structures (anterior capsule and periosteum). Further evidence of the nerve to vastus medialis involvement in adductor canal blocks comes from a recent study of healthy volunteers that compared the loss
Letters to the Editor
of quadriceps motor strength after both femoral and adductor canal blockade.4 The 8% reduction in motor function observed in subjects undergoing adductor canal block (albeit drastically less marked than the 40% reduction from a femoral nerve block) could be not explained if the only affected nerve were the saphenous nerve. Most reports to date have used a volume of local anesthetic of 20 to 30 mL for the subsartorial injection. Although the spread of this volume has not been rigorously examined in live patients, Lund et al5 documented by magnetic resonance imaging, a wide area of spread from 7 cm proximal to the patella to 8 cm distal to the femoral triangle after 30 mL of injectate placed into the adductor canal at the midthigh. This range included the distal part of canal adjacent to the posterior branch of the obturator nerve, the femoral artery, and the saphenous nerve. Similarly, Davis et al6 reported a series of cadaveric injections with 30 mL of methylene blue dye that demonstrated proximal spread toward the area of femoral nerve separation into anterior and posterior divisions. They also describe spread and involvement of the nerve to vastus medialis within the canal during their dissections. Arguably, a small volume of local anesthetic could allow for selective saphenous nerve block in the adductor canal with the intention of providing analgesia to the medial aspect of the ankle/ foot. However, selective saphenous nerve blockade will likely be insufficient to provide knee analgesia. Our current knowledge of anatomy suggests that a more extensive blockade of all the nerves coursing in the adductor canal would provide superior analgesia to both superficial and deep anteromedial knee structures. Therefore, at the present time, we feel that the term “adductor canal block” (rather than saphenous nerve block) more accurately describes an injection of local anesthetic that targets all nerves coursing
Reply to Dr Andersen and Zaric Accepted for Publication: February 6, 2014. To the Editor: e thank Drs Andersen and Zaric1 for their interest in our article2 and for furthering the discussion into the anatomic details of subsartorial injection of local anesthetic. We concur with these
W
FIGURE 1. Adductor canal at midthigh. A indicates artery; SN, saphenous nerve; VMN, nerve to vastus medialis.
© 2014 American Society of Regional Anesthesia and Pain Medicine
257
Copyright © 2014 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this article is prohibited.
Anesthesia for Clavicular Fracture and Surgery Accepted for Publication: December 18, 2013. To the Editor: e read with great interest the inaugural section “Daring Discourse” by Tran et al1 regarding analgesia for clavicular fracture and surgery. We agree with the authors’ qualified endorsement of Dejerine’s description of dual innervation of the clavicle by both the cervical and brachial plexus.2 In our experience, the true measure of success for nerve blockade is efficacy for surgical anesthesia. To this end, we wish to report a recent case where surgical fixation of the clavicle was performed solely under combined superficial cervical plexus and supraclavicular brachial plexus blockade using a single-needle insertion. A 17-year-old male patient presented for open reduction and internal fixation of a displaced fracture of the left clavicle. With patient consent, ostensibly for a nerve block for postoperative analgesia, an ultrasoundguided superficial cervical plexus block was first performed with a 22-gauge, 50-mm insulated needle using an in-plane technique. Fifteen milliliters of 0.5% ropivacaine and 0.125% bupivacaine [1:1] was injected deep to the prevertebral fascia between the sternocleidomastoid muscle and the anterior scalene muscle where the superficial cervical plexus traverses. The needle was then simply advanced to a location adjacent to the brachial plexus at a low interscalene location. Five milliliters of the same solution was deposited at this location (Fig. 1). Within 10 minutes of block completion, the patient had lost temperature sensation from the mandibular angle to the C5
W
Regional Anesthesia and Pain Medicine • Volume 39, Number 3, May-June 2014
dermatome of the anterior chest wall. Contemporaneously, he developed a complete motor block of the upper limb. This was deemed satisfactory anesthesia for the surgical procedure and the patient subsequently consented to an awake procedure. Performed in the beach chair position, the procedure lasted for 105 minutes. The patient reported being comfortable throughout the surgery. Despite no clinical evidence of respiratory distress, this combination of nerve blocks will undoubtedly lead to phrenic nerve blockade. We agree with Tran et al’s call for further clarification of the sensory innervation of the clavicle. A successful practice in ultrasound-guided regional anesthesia is based on a solid understanding of conventional anatomy. Occasionally, sonoanatomy may reciprocate and contribute to our existing knowledge.
Derek Dillane, FCARCSI Timur Ozelsel, MD, DESA Kristen Gadbois, FRCPC Department of Anesthesiology and Pain Medicine University of Alberta Edmonton, Alberta, Canada
The authors declare no conflict of interest. REFERENCES 1. Tran DQH, Tiyaprasertkul W, Gonzalez A. Analgesia for clavicular fracture and surgery: a call for evidence. Reg Anesth Pain Med. 2013;38:539–543. 2. Dejerine J. Syndromes sensitifs. Semeiologie des Affections du Systeme Nerveux. Paris, France: Masson; 1914.
FIGURE 1. Ultrasound scan of the left neck showing the subclavian artery (SA), brachial plexus (white circle), anterior scalene muscle (ASM), sternocleidomastoid muscle (SCM), and block needle (white line arrows). Spread of local anesthetic (LA) can be seen (left) deep to the prevertebral fascia (white solid arrows) where the superficial cervical plexus is found. The needle was then advanced to block the brachial plexus at a low interscalene location (right).
256
Adductor Canal Block or Midthigh Saphenous Nerve Block Same Same but Different Name! Accepted for Publication: October 23, 2013.
To the Editor: e read with great interest the study by Perlas et al,1 which, like our recent article,2 supports the idea that the addition of a saphenous nerve block to local infiltration analgesia improves the analgesia and early ambulation after total knee arthroplasty (TKA). Although we placed our injections in the adductor canal around the saphenous nerve, we chose not to use the term “adductor canal block.” This term is based on the theoretical assumption that a large volume of local anesthetic in the adductor canal would not only block the saphenous nerve but also other nerves that could be lying in the adductor canal. To our knowledge, no convincing studies have been published that clearly indicate that nerves other than the saphenous nerve are blocked by an injection of local anesthetic in the adductor canal. Perlas refers to the study by Horner and Dellon3 regarding nerves in the adductor canal (Hunter canal). This study, however, is not about the adductor canal; the authors are unclear about how the adductor canal is perceived and do not describe it. Thiel4 made an excellent anatomical atlas using dissection photoimages to visualize and describe the adductor canal and its contents. Only the saphenous nerve is described as lying in the adductor canal. The same applies to the study by Tubbs et al,5 which is also referenced by Perlas. What is called the adductor canal block is, in fact, equivalent to the midthigh saphenous nerve block. Other nerve branches may lie in close proximity to the canal but not in the canal at midthigh level and may not be affected by an injection in the adductor canal. The medial branch of the nerve to the vastus medialis muscle lies close to the adductor canal, but it is in the muscle or just under the muscle fascia at the midthigh level; this can be seen ultrasonographically. The anterior cutaneous branch of the obturator nerve is inconsistent and lies close to the adductor canal but not in the canal,4 and the posterior branch of the obturator nerve may pass through the adductor hiatus and could be blocked at this point on its way to the posterior knee capsule,6 but this is not shown in any study. These nerve branches may not play any
W
© 2014 American Society of Regional Anesthesia and Pain Medicine
Copyright © 2014 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this article is prohibited.
Regional Anesthesia and Pain Medicine • Volume 39, Number 3, May-June 2014
major role as pain-mediating nerves after TKA where the incision is made through the anterior knee capsule. The saphenous nerve innervates a major part of the anterior knee capsule and is, therefore, the main target for an ultrasound-guided nerve blockade after TKA. A large volume “to fill the adductor canal” may not be needed. Henning Lykke Andersen, MD Department of Anesthesiology Herlev University Hospital Copenhagen, Denmark
Dusanka Zaric, MD, PhD Department of Anesthesiology Frederiksberg University Hospital Copenhagen, Denmark
The authors declare no conflict of interest. REFERENCES 1. Perlas A, Kirkham KR, Billing R, et al. The impact of analgesic modality on early ambulation following total knee arthroplasty. Reg Anesth Pain Med. 2013;38:334–339. 2. Andersen HL, Gyrn J, Møller L, Christensen B, Zaric D. Continuous saphenous nerve block as supplement to single-dose local infiltration analgesia for postoperative pain management after total knee arthroplasty. Reg Anesth Pain Med. 2012;38:106–111. 3. Horner G, Dellon AL. Innervation of the human knee joint and implications for surgery. Clin Orthop Relat Res. 1994;301:221–226. 4. Thiel W. Adductor canal. In: Thiel W, ed. Photographic Atlas of Practical Anatomy I (Abdomen, Lower Limb): 1 vol. 1st ed. Berlin, Germany: Springer; 1997:228–235. 5. Tubbs RS, Loukas M, Shoja MM, Apaydin N, Oakes WJ, Salter EG. Anatomy and potential clinical significance of the vastoadductor membrane. Surg Radiol Anat. 2007; 29:569–573. 6. Kumka M. Critical sites of entrapment of the posterior division of the obturator nerve: anatomical considerations. J Can Chiropr Assoc. 2010;54:33–42.
authors that there are questions yet to be addressed regarding this analgesic intervention for an expanding range of surgical procedures. The most consistent neural target for subsartorial, midthigh injection is indeed the saphenous nerve. However, there is evidence that other peripheral nerves also travel in the adductor canal and provide additional innervation to the cutaneous, capsular, and articular aspects of the knee joint. Horner and Dellon3 explored the innervation of the knee joint. They refer to Hunter canal (an eponym equivalent to the adductor canal) to describe the aponeurotic space below the sartorius muscle and extending from the femoral triangle to the adductor hiatus. Horner and Dellon found that the canal consistently contained 1 or more infrapatellar branches of the saphenous nerve but also superficial branches from the medial cutaneous femoral nerve in 60.8% of cadavers. Similarly, they identified that the medial retinacular nerve (a terminal branch of the nerve to vastus medialis) penetrates the muscle bulk and provides innervation to the medial capsule of the joint. Although less consistently, they also observed the anterior branch of the obturator nerve entering the canal through the adductor magnus and contributing to perigenicular innervation in 11% of cadavers.3 We agree that the nerve to vastus medialis (a branch of the femoral nerve) can often be visualized on ultrasound. The bulk of this nerve lies within the adductor canal (deep to the vastoadductor membrane), although small muscular branches may be seen leaving the canal often accompanied by small arterial branches (Fig. 1). More distally, large terminal branches of this nerve cross the bulk of the muscle and provide innervation to deep articular structures (anterior capsule and periosteum). Further evidence of the nerve to vastus medialis involvement in adductor canal blocks comes from a recent study of healthy volunteers that compared the loss
Letters to the Editor
of quadriceps motor strength after both femoral and adductor canal blockade.4 The 8% reduction in motor function observed in subjects undergoing adductor canal block (albeit drastically less marked than the 40% reduction from a femoral nerve block) could be not explained if the only affected nerve were the saphenous nerve. Most reports to date have used a volume of local anesthetic of 20 to 30 mL for the subsartorial injection. Although the spread of this volume has not been rigorously examined in live patients, Lund et al5 documented by magnetic resonance imaging, a wide area of spread from 7 cm proximal to the patella to 8 cm distal to the femoral triangle after 30 mL of injectate placed into the adductor canal at the midthigh. This range included the distal part of canal adjacent to the posterior branch of the obturator nerve, the femoral artery, and the saphenous nerve. Similarly, Davis et al6 reported a series of cadaveric injections with 30 mL of methylene blue dye that demonstrated proximal spread toward the area of femoral nerve separation into anterior and posterior divisions. They also describe spread and involvement of the nerve to vastus medialis within the canal during their dissections. Arguably, a small volume of local anesthetic could allow for selective saphenous nerve block in the adductor canal with the intention of providing analgesia to the medial aspect of the ankle/ foot. However, selective saphenous nerve blockade will likely be insufficient to provide knee analgesia. Our current knowledge of anatomy suggests that a more extensive blockade of all the nerves coursing in the adductor canal would provide superior analgesia to both superficial and deep anteromedial knee structures. Therefore, at the present time, we feel that the term “adductor canal block” (rather than saphenous nerve block) more accurately describes an injection of local anesthetic that targets all nerves coursing
Reply to Dr Andersen and Zaric Accepted for Publication: February 6, 2014. To the Editor: e thank Drs Andersen and Zaric1 for their interest in our article2 and for furthering the discussion into the anatomic details of subsartorial injection of local anesthetic. We concur with these
W
FIGURE 1. Adductor canal at midthigh. A indicates artery; SN, saphenous nerve; VMN, nerve to vastus medialis.
© 2014 American Society of Regional Anesthesia and Pain Medicine
257
Copyright © 2014 American Society of Regional Anesthesia and Pain Medicine. Unauthorized reproduction of this article is prohibited.
