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.
Letters to the Editor
in the adductor canal with the intention of providing analgesia to both superficial and deep anteromedial knee structures. We believe more detailed anatomical studies are warranted to further improve our current understanding of the innervation of the knee joint. Kyle R. Kirkham, MD, FRCPC Anahi Perlas, MD, FRCPC Department of Anesthesia and Pain Management Toronto Western Hospital University Health Network University of Toronto Toronto, Canada
The authors declare no conflict of interest. REFERENCES 1. Andersen HL, Zaric D. Adductor Canal Block or Midthigh Saphenous Nerve Block: Same Same but Different Name. Reg Anesth Pain Med. 2014;39:256–257. 2. 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. 3. Horner G, Dellon AL. Innervation of the human knee joint and implications for surgery. Clin Orthop Relat Res. 1994;301:221–226. 4. Jaeger P, Nielsen ZJK, Henningsen MB, Hilsted KL, Mathiesen O, Dahl JB. Adductor canal block versus femoral nerve block and quadriceps strength. Anesthesiology. 2013;188:409–415. 5. Lund J, Jenstrup MT, Jaeger P, Sorensen AM, Dahl JB. Continuous adductor-canal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results. Acta Anaesthesiol Scand. 2011;55:14–19. 6. Davis JJ, Bond TS, Swenson JD. Adductor canal block more than just the saphenous nerve. Reg Anesth Pain Med. 2009;34: 618–619.
Anesthesia for Clavicular Fracture Selective Supraclavicular Nerve Block Is the Key Accepted for publication: December 9, 2013. To the Editor: e have read with interest the paper from Tran et al1 regarding regional blockade for clavicular fracture. In their
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Regional Anesthesia and Pain Medicine • Volume 39, Number 3, May-June 2014
paper, they describe the difficulty in establishing an adequate regional analgesic strategy given the poorly defined innervation of the clavicle found in the literature. The innervation includes the supraclavicular nerve (SN), branch of the superficial cervical plexus, deep cervical plexus branches, and brachial plexus branches such as subclavian, suprascapular, and long thoracic nerves. There also are several confounding factors, as local anesthetic migration may occur between the interscalene and superficial cervical plexus block approaches. For the last 2 years, we have been using routinely a low-volume (1.5–2 mL) selective SN blockade, together with a low-volume (8–15 mL) brachial plexus supraclavicular approach, for nearly all shoulder surgery procedures. This is an alternative to the interscalene block in an attempt to avoid nerve lesion and phrenic nerve blockade. With this approach, we have achieved adequate depth of blockade for clavicle surgery, together with light sedation. In the case of a clavicle fracture, in our opinion, the SN is the most frequently implicated nerve, specifically, the intermediate branch, which pierces the clavicle in 1% to 4% of the population2 and innervates, at least, the proximal half of the clavicle. Maybin et al3 made the first and only description of its selective blockade in 2011. The most suitable approach to the SN is made at an intermediate point between the interscalene and the supraclavicular approaches, about 2 to 3 cm above the clavicle, after crossing the prevertebral layer of the deep cervical fascia and is positioned between that and the investing layer. At this point, the SN can usually be identified as a single nerve, just before giving off its branches. Thus, an injection distant from the phrenic nerve and at different fascial compartments is possible. Although its identification is not easy, it is possible in most patients, lessening the risk of damaging other branches of the superficial cervical plexus, as has been shown in the literature.4 There is some variability between patients, and occasionally it is possible to identify the single nerve; whereas in other patients, it may have to be divided into 2 branches, thus becoming necessary to inject low local anesthetic volumes at both nerves (Fig. 1). In our experience, the combination of the block described previously and a supraclavicular brachial plexus block with low volumes allows effective blockade for clavicle fracture surgery. The usage of low local anesthetic volumes reduces the risk of phrenic nerve blockade to the point of making it nonexistent.5 Although it cannot be proven, we believe it is very unlikely
that the low volumes of local anesthetic that we use to perform the supraclavicular brachial plexus approach could block the long thoracic nerve, which emerges from C5 and C6 cervical roots and immediately, after appearing in the interscalenic groove, pierces the middle scalene muscle. We believe that the most accurate description of the clavicle innervation are the ones made by Gray6 and Dejerine,7 except regarding the remarks made by the latter about the long thoracic nerve which in our clinical experience seems inaccurate. The question that arises is whether the brachial plexus block is necessary. We share the opinion of Tran et al that future randomized trials are required to determine which constitutes the best option for clavicular fractures management.
Luis Fernando Valdés-Vilches, MD Manuel Jesús Sánchez-del Águila, MD FCARCSI Anesthesia Department Hospital Costa del Sol Marbella, Spain
The authors declare no conflict of interest. REFERENCES 1. Tran DQH, Tiyaprasertkul W, González AP. Analgesia for clavicular fracture and surgery: a call for evidence. Reg Anesth Pain Med. 2013;38:1–5. 2. Tubbs RS, Salter EG, Oakes WJ. Anomaly of the supraclavicular nerve: case report and review of the literature. Clin Anat. 2006;19:599–601. 3. Maybin J, Townsley P, Bedforth N, Allan A. Ultrasound guided supraclavicular nerve blockade: first technical description and the relevance for shoulder surgery under regional anaesthesia. Anaesthesia. 2011;66:1048–1060. 4. Fredrickson MJ. Superficial cervical plexus neuropathy with chronic pain after superficial cervical plexus block and interscalene catheter placement. Reg Anesth Pain Med. 2011;36:206. 5. Renes SH, Spoormans HH, Gielen MJ, Rettig HC, Van Geffen GJ. Hemidiaphragmatic paresis can be avoided in ultrasound-guided supraclavicular brachial plexus block. Reg Anesth Pain Med. 2009;34:595–599. 6. Gray AT. Superficial cervical plexus block. In: Gray AT, ed. Atlas of Ultrasound-Guided Regional Anesthesia. 2nd ed. Philadelphia, Pa: Saunders; 2012. 7. Dejerine J. Syndromes sensitifs. In: Dejerine J, ed. Semiologie des Affections du Systeme Nerveux. Paris, France: Masson; 1914.
© 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.
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.
Letters to the Editor
in the adductor canal with the intention of providing analgesia to both superficial and deep anteromedial knee structures. We believe more detailed anatomical studies are warranted to further improve our current understanding of the innervation of the knee joint. Kyle R. Kirkham, MD, FRCPC Anahi Perlas, MD, FRCPC Department of Anesthesia and Pain Management Toronto Western Hospital University Health Network University of Toronto Toronto, Canada
The authors declare no conflict of interest. REFERENCES 1. Andersen HL, Zaric D. Adductor Canal Block or Midthigh Saphenous Nerve Block: Same Same but Different Name. Reg Anesth Pain Med. 2014;39:256–257. 2. 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. 3. Horner G, Dellon AL. Innervation of the human knee joint and implications for surgery. Clin Orthop Relat Res. 1994;301:221–226. 4. Jaeger P, Nielsen ZJK, Henningsen MB, Hilsted KL, Mathiesen O, Dahl JB. Adductor canal block versus femoral nerve block and quadriceps strength. Anesthesiology. 2013;188:409–415. 5. Lund J, Jenstrup MT, Jaeger P, Sorensen AM, Dahl JB. Continuous adductor-canal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results. Acta Anaesthesiol Scand. 2011;55:14–19. 6. Davis JJ, Bond TS, Swenson JD. Adductor canal block more than just the saphenous nerve. Reg Anesth Pain Med. 2009;34: 618–619.
Anesthesia for Clavicular Fracture Selective Supraclavicular Nerve Block Is the Key Accepted for publication: December 9, 2013. To the Editor: e have read with interest the paper from Tran et al1 regarding regional blockade for clavicular fracture. In their
W 258
Regional Anesthesia and Pain Medicine • Volume 39, Number 3, May-June 2014
paper, they describe the difficulty in establishing an adequate regional analgesic strategy given the poorly defined innervation of the clavicle found in the literature. The innervation includes the supraclavicular nerve (SN), branch of the superficial cervical plexus, deep cervical plexus branches, and brachial plexus branches such as subclavian, suprascapular, and long thoracic nerves. There also are several confounding factors, as local anesthetic migration may occur between the interscalene and superficial cervical plexus block approaches. For the last 2 years, we have been using routinely a low-volume (1.5–2 mL) selective SN blockade, together with a low-volume (8–15 mL) brachial plexus supraclavicular approach, for nearly all shoulder surgery procedures. This is an alternative to the interscalene block in an attempt to avoid nerve lesion and phrenic nerve blockade. With this approach, we have achieved adequate depth of blockade for clavicle surgery, together with light sedation. In the case of a clavicle fracture, in our opinion, the SN is the most frequently implicated nerve, specifically, the intermediate branch, which pierces the clavicle in 1% to 4% of the population2 and innervates, at least, the proximal half of the clavicle. Maybin et al3 made the first and only description of its selective blockade in 2011. The most suitable approach to the SN is made at an intermediate point between the interscalene and the supraclavicular approaches, about 2 to 3 cm above the clavicle, after crossing the prevertebral layer of the deep cervical fascia and is positioned between that and the investing layer. At this point, the SN can usually be identified as a single nerve, just before giving off its branches. Thus, an injection distant from the phrenic nerve and at different fascial compartments is possible. Although its identification is not easy, it is possible in most patients, lessening the risk of damaging other branches of the superficial cervical plexus, as has been shown in the literature.4 There is some variability between patients, and occasionally it is possible to identify the single nerve; whereas in other patients, it may have to be divided into 2 branches, thus becoming necessary to inject low local anesthetic volumes at both nerves (Fig. 1). In our experience, the combination of the block described previously and a supraclavicular brachial plexus block with low volumes allows effective blockade for clavicle fracture surgery. The usage of low local anesthetic volumes reduces the risk of phrenic nerve blockade to the point of making it nonexistent.5 Although it cannot be proven, we believe it is very unlikely
that the low volumes of local anesthetic that we use to perform the supraclavicular brachial plexus approach could block the long thoracic nerve, which emerges from C5 and C6 cervical roots and immediately, after appearing in the interscalenic groove, pierces the middle scalene muscle. We believe that the most accurate description of the clavicle innervation are the ones made by Gray6 and Dejerine,7 except regarding the remarks made by the latter about the long thoracic nerve which in our clinical experience seems inaccurate. The question that arises is whether the brachial plexus block is necessary. We share the opinion of Tran et al that future randomized trials are required to determine which constitutes the best option for clavicular fractures management.
Luis Fernando Valdés-Vilches, MD Manuel Jesús Sánchez-del Águila, MD FCARCSI Anesthesia Department Hospital Costa del Sol Marbella, Spain
The authors declare no conflict of interest. REFERENCES 1. Tran DQH, Tiyaprasertkul W, González AP. Analgesia for clavicular fracture and surgery: a call for evidence. Reg Anesth Pain Med. 2013;38:1–5. 2. Tubbs RS, Salter EG, Oakes WJ. Anomaly of the supraclavicular nerve: case report and review of the literature. Clin Anat. 2006;19:599–601. 3. Maybin J, Townsley P, Bedforth N, Allan A. Ultrasound guided supraclavicular nerve blockade: first technical description and the relevance for shoulder surgery under regional anaesthesia. Anaesthesia. 2011;66:1048–1060. 4. Fredrickson MJ. Superficial cervical plexus neuropathy with chronic pain after superficial cervical plexus block and interscalene catheter placement. Reg Anesth Pain Med. 2011;36:206. 5. Renes SH, Spoormans HH, Gielen MJ, Rettig HC, Van Geffen GJ. Hemidiaphragmatic paresis can be avoided in ultrasound-guided supraclavicular brachial plexus block. Reg Anesth Pain Med. 2009;34:595–599. 6. Gray AT. Superficial cervical plexus block. In: Gray AT, ed. Atlas of Ultrasound-Guided Regional Anesthesia. 2nd ed. Philadelphia, Pa: Saunders; 2012. 7. Dejerine J. Syndromes sensitifs. In: Dejerine J, ed. Semiologie des Affections du Systeme Nerveux. Paris, France: Masson; 1914.
© 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.
