Anaesthesia, 1992, Volume 47, pages 120- 124
Suprascapular nerve block A new approach for the management of frozen shoulder
M . R. WASSEF
Summary A new approach for the management of frozen shoulder associated with reflex sympathetic dystrophy is presented. A suprascapular nerve block was performed by needle insertion behind the lateral end of the clavicle at its junction with the insertion of the trapezius muscle; the needle was directed downwards and backwardx The suprascapular nerve was identified by its response to nerve stimulation. Three ml of 0.25% bupivacaine with 1:200 000 adrenaline was injected. The block was repeated twice weekly for a total of 2-4 treatments. Evaluation of the eficacy of the block was achieved by comparing subjective pain scores and passive range of movement before the first block and after the final one. Highly signiJicant improvements were obtained. The choice of blockade of the suprascapular nerve is a new concept for the management of the frozen shoulder of reflex sympathetic dystrophy. This is based on the fact that the nerve contains a high proportion of sympatheticfibres supplying the shoulder joint. The new approach proved to be simple, highly successful, and reproducible. Key words Anatomy; nerve, suprascapular. Anaesthetic technique; regional, suprascapular nerve. Complications; reflex sympathetic dystrophy.
The term 'frozen shoulder' is used to describe a painful stiffness of the shoulder joint characterised by limitation of movement. Various aetiological factors could give rise to this condition including the shoulder-hand syndrome of reflex sympathetic dystrophy (RSD) [I]. Clinically, the frozen shoulder may be the only presenting sign of RSD or it may be associated with hand involvement. A sizeable proportion of frozen shoulder cases have been found following myocardial infarction, hemiplegia and other disorders [2]. The management of the frozen shoulder associated with RSD includes physiotherapy and sympathetic blockade in the form of stellate ganglion or brachial plexus block [3]. Shoulder pain, in general, can be alleviated by suprascapular nerve block [4]. The technique of suprascapular nerve blockade, as described in textbooks, involves a posterior approach, the needle entering above the scapula [S]. Since sympathetic fibres supplying the shoulder joint run in the suprascapular nerve, it is conceivable that sympathetic blockade to the shoulder could be achieved at the level of this nerve. The aim of this study was to present a new and simple approach to the suprascapular nerve, whereby the needle is inserted via an anterior approach above the clavicle, and
to evaluate its efficacy in the management of the frozen shoulder of reflex sympathetic dystrophy.
Methods Institutional approval was given for the study and informed consenting patients with the diagnosis of frozen shoulder associated with reflex sympathetic dystrophy were referred for pain relief management. All patients complained of diffuse dull pain, tenderness and variable swelling of the affected shoulder joint, and limitation in range of passive movement. The case history of the frozen shoulder was reviewed for each patient. Demographic data obtained included age, sex, duration of shoulder pain and disability and presumed aetiology. Symptoms were graded according to severity of the pain; grade 1: severe, grade 2: moderate and grade 3: mild. The patient evaluation consisted of the following: (a) objective joint pain score: this was obtained by palpation of the glenohumeral joint and scored as follows: 0 = no pain, 1 = mild pain to deep palpation, 2 = severe pain to deep palpation, 3 = severe pain to mild palpation and 4 = hyperaesthesia. (b) passive range of movement score (PROM): this was determined as follows: ( I ) ability to elevate the arm through 180",
M.R. Wassef, MB, BCh, DA, FFARCS, Assistant Professor of Anesthesiology, Mount Sinai School of Medicine, New York, USA. Presented in part to the Eighth European Congress of Anaesthesiology, September, 1990, Warsaw, Poland. Accepted 3 June 1991. 0003-2409/92/020120 +05 $03.00/0
@ 1992 The Association of Anaesthetists of Gt Britain and Ireland
120
Suprascapular nerve block
Trapezius
\
121
through the suprascapular notch and enters the supraspinous fossa, where it gives off several branches including articular branches to the acromioclavicular and the shoulder joints. It then runs deep to the supraspinatus muscle and curves round the lateral border of the spine of the scapula to gain the infraspinous fossa where it gives off more branches including articular filaments to the shoulder joint. The coracoid process arises from the upper border of the head of the scapula and is bent sharply so as to project forwards and slightly laterally. Its medial margin is almost aligned with the suprascapular notch, and its tip can be felt through the skin [6].
Lotera I deltoid
Fig. 1. A lateral view of the shoulder depicting the point of needle entry, marked X, at the junction of the trapezius muscle and the clavicle.
(2) ability to elevate the arm above the horizontal level, (3) ability to elevate the arm to the horizontal level, (4) ability to elevate the arm to below the horizontal level and (5) inability to move the arm. Active range of movement was not measured in this study since most of the patients had CNS-related conditions. (c) Visual analogue score (VAS): the patient was asked to mark a 100 mm scale where 0 indicated no pain and 100 indicated extreme severe pain. These tests were carried out prior to the first block and after the final one. Anatomy
The suprascapular nerve is a large nerve which arises from the upper trunk of the brachial plexus. It runs laterally, posteriorly and inferiorly deep to the omohyoid and trapezius muscles, but superficial to the brachial plexus, to reach the superior border of the scapula. Here it passes
Technique
The patient is placed in the sitting position. The landmarks used are the coracoid process, the trapezius muscle and the clavicle. The point of entry of the needle is marked at the junction of the medial border of the trapezius muscle and the posterior border of the lateral third of the clavicle (Fig. I). This point is above the clavicle, and lies at the apex of a triangle set in the perpendicular plane whose base is a line formed by the medial side of the tip of the coracoid process anteriorly and the suprascapular notch posteriorly (Fig. 2). Under aseptic conditions a 22 gauge needle was inserted and directed backwards and downwards with slight medial inclination, along the posterior side of the triangle. A peripheral nerve stimulator was employed for identification of the suprascapular nerve. Nerve blockade was produced by injection of 3.0 ml of 0.25% bupivacaine with 1:200000 adrenaline. All blocks proved to be uneventful. The block was repeated twice weekly. The total number of blocks for each patient varied according to the diminution of pain and improvement in the passive range of shoulder movement. During and after suprascapular nerve block therapy, patients were maintained on a physiotherapy programme.
Fig. 2. Superior view of the shoulder depicting the suprascapular nerve in relation to the clavicle and the coracoid process.
122
M . R . Wassef
Fig. 3. Objective joint pain score before and after the suprascapular nerve block therapy. 20.0
40.0
60.0
80.0
100.0
Visuol onologue scale (rnrn)
Analysis of data Data of various parameters were calculated as mean (SD). Comparison between the parametric variables were performed using Student’s t-test. Statistical significance was considered at a level of p < 0.05.
Fig. 5. Correlation between the visual analogue scale and the passive range of movement, before and after the suprascapular nerve block therapy. Y = 1.052+0.039X; r = 0.986; p < 0.001.
blocks performed was 3.22 (SD 0.4) (range 2-4). Depth of needle insertion was 3.90 (SD 0.19) cm (range 3-5 cm).
Results Frozen shoulder characteristics
Patient characteristics Nine patients with the frozen shoulder of RSD received suprascapular nerve block therapy. Their mean age was 60.33 (SD 5.41) years (range 32-76) and all were female. The precipitating aetiological factors were mainly central nervous system pathology resulting in paraplegia in five patients, cervical cord injury in one, brachial plexus injury in one patient and trauma in two patients. The mean time between the development of symptoms and evaluation was 9.56 (SD 1.09) months (range 2-12). The mean number of
All patients presented with the shoulder component of RSD affecting one side only. The chief complaint was shoulder pain and restricted active movement in the nonparaplegic patients. Symptom grades were: grade 1 (severe) in three patients and grade 2 (moderate) in six patients. The presenting sensory phenomena associated with pain were hyperaesthesia in all patients (100Y0)and hyperalgesia in six. The subjective description of pain in grade 1 patients ( n = 3) was burning in one and lancing in two while in all grade 2 patients (n = 6) it was dull and aching. Pain scores
Preblocks
Postblocks
Fig. 4. Visual analogue scale (VAS) before and after the suprascapular nerve block therapy.
There was a significant decrease in the mean objective joint pain score indicating improvement in the patient’s tolerance to deep pressure applied to the shoulder joint. Overall scores before and after the block therapy were 3.1 1 (SD 0.11) and 0.56 (SD 0.18) respectively, p < 0.001, (Fig. 3). There was a significant decrease in the visual analogue scores (VAS) indicating the patient’s appreciation of pain alleviation. Mean scores before and after the block therapy were 85.56 (SD 2.94) and 12.78 (SD 3.55) respectively, p < 0.001. The mean percentage of improvement was 86.00 (SD 3.72) (Fig. 4). A highly significant correlation was found between the visual analogue score and the passive range of movement obtained before and after the blocks r = 0.986, p < 0.001. The regression equation calculated was; Y = 1.052 + 0.039 X,where Y is the passive range of movement score, and X is the visual analogue score in mm (Fig. 5). A significant improvement was obtained in the passive range of movement (PROM) score. The mean scores before
Suprascapular nerve block 5.0
4.0
3.0
? 8 cn 2.0
1.0
Preblocks
Postblocks
Fig. 6. Passive range of movement (PROM) score of the shoulder before and after the suprascapular nerve block therapy.
and after the block therapy were 4.33 (SD 0.50) and 1.56 (SD 0.18) respectively p < 0.001, (Fig. 6). Discussion
The frozen shoulder is frequently described as either the sole presenting manifestation or a component of the shoulder-hand syndrome of reflex sympathetic dystrophy (RSD) [I]. Two common aetiological factors are associated
123
with this disease, namely myocardial infarction and hemiplegia, although other factors such as trauma could predispose. The relationship between hemiplegia and the signs and symptoms of the shoulder-hand syndrome was emphasised by deTakats [7] and Evans [8]. In posthemiplegic shoulder-hand syndrome patients the pain and restricted movement disappears with sympathetic blockade [9], in conjunction with a programme of physiotherapy. Suprascapular nerve block is said to be useful in the management of severe painful conditions of the shoulder joint, but there is little reference to the use of suprascapular nerve block for the management of pain in the frozen shoulder of RSD. The present work showed that the anterior approach to blockade of the suprascapular nerve produced a highly significant reduction of pain and improved passive range of movement in the frozen shoulder of RSD. There were two aims behind this work: to present a new approach to blockade of the suprascapular nerve, and to demonstrate the efficacy of this block in the management of the frozen shoulder of RSD. The anterior approach is of particular value with bedridden patients as it can be performed while the patient is lying in bed. All that is required is exposure of the front part of the shoulder and neck. The traditional posterior approach requires turning and positioning; a strenuous task for the nursing staff as well as for the patient. The anterior approach proved to provide an easy and reproducible access to the suprascapular nerve. Suprascapular nerve block produces sympathetic blockade similar to that obtained with stellate ganglion
Fig. 7. X ray of the shoulder area after injection of local anaesthetic mixed with radio-opaque material
124
M .R . Wassef
blockade but spares the patient from the inherent risks of the latter technique [lo]. The most serious complication of the traditional approach to suprascapular nerve blockade is pneumothorax; the incidence is reported to be less than one percent [I I]. This can occur if the needle is passed above the upper border of the scapula and advanced too far anteriorly, piercing the lungs. It is highly unlikely for this complication to occur with the anterior approach, since the needle is directed posteriorly and from a higher angle. Also, the point of needle entry is away from the dome of the lung and its direction is in a plane which is perpendicular t o the ribs. This makes penetration of the intercostal space highly unlikely. Figure 7 is an X ray showing the needle away from the thoracic cage. The needle tip is superficial to the suprascapular notch, showing that the suprascapular nerve can be blocked a t a superficial level and before it reaches the suprascapular foramen. A number of hypotheses have been proposed concerning the mechanism of reflex sympathetic dystrophy [12, 131. Roberts [ 141 suggested that trauma initially activates unmyelinated C-nociceptors, which in turn activate and sensitise wide dynamic range (WDR) neurones in the dorsal horn whose axons ascend to higher centres. This sensitisation persists, so that the WDR neurones now respond to activity in large-diameter A-mechanoreceptive low threshold afferents, which are activated by light touch or brushing. Moreover, these sensitised WDR neurones respond to A-mechanoreceptive activity initiated by sympathetic efferent action on sensory receptors in the absence of cutaneous stimulation and thus produce spontaneous pain or what Roberts calls ‘sympathetically mediated pain’. Nathan [IS]has used the abnormal state of the dorsal horn as an explanation for RSD caused not only by limb injury but also by central nervous system pathology. In conclusion, sympathetic blockade at the level of the suprascapular nerve for the management of the frozen shoulder of RSD proved to be a highly specific procedure,
in terms of sympathetically mediated shoulder pain. The anterior approach to the suprascapular nerve is a new, simple, convenient and reproducible technique offering easy accessibility to the suprascapular nerve in the bedridden patient, as opposed to the traditional posterior approach.
References [I] STEINBROCKER 0. The shoulder hand syndrome. Americun Journal of Medicine 1947; 3: 402-7. 0, ARGYROSTG. The shoulder-hand [2] STEINBROCKER syndrome: present status as a diagnostic and therapeutic entity. Medical Clinics of North America 1958; 4 5 15. BONICAJJ. BUCKLEY FP. Regional analgesia - with local anesthetics. In: BONICAJJ, ed. The managemenf of pain. Philadelphia: Lea & Febiger, 1990: 1933, 1904. BONICAJJ, CAILLET R. General considerations of pain in the JJ, ed. The management of neck and upper limb. In: BONICA pain. Philadelphia: Lea & Febiger, 1990: 826. ERIKSONE. Illustrated handbook in regional anaesthesia, Copenhagen: Munksgaard, 1969: 81. GRAYH. Anatomy; descriptive and applied, 30th edn. London: Longmans, Green and Co, 1949: 1123-4, 343. DE TAKATS G. Causalgic states in peace and war. Journal of the American Medical Association 1945; 128: 699-740. EVANSJA. Reflex sympathetic dystrophy. Surgical Clinics of North America 1946; 2: 780-90. PW, SCOTTGD. Pain due to lesions of the LOHL, NATHAN central nervous system removed by sympathetic block. British Medical Journal 1981; 282 1026-8. COUSINS,MJ, BRIDENBAUGH, PO. eds. Neural blockade in clinical anesthesia and management of pain. Philadelphia: Lippincott, 1980: 539, 549. MOOREDC. Regional block, 4th edn. Springfield: Thomas, 1965: 300-3. LIVINGSTON WK. Pain mechanisms: a physiologic interpretation of causalgia and its related slates. New York: Macmillan, 1943: 83-127. R. Phantom limb pain: Implications for treatment [I31 MELZACK of pathologic pain. Anesthesiology 1971, 3 5 409-19. [I41 ROBERTS WJ. An hypothesis on the physiological basis for causalgia and related pains. Pain 1986; 2 4 297-31 I . [I51 NATHANPW. Pain and the sympathetic nervous system. Journal of the Autonomic Nervous System 1983; 7: 363-70.
Suprascapular nerve block A new approach for the management of frozen shoulder
M . R. WASSEF
Summary A new approach for the management of frozen shoulder associated with reflex sympathetic dystrophy is presented. A suprascapular nerve block was performed by needle insertion behind the lateral end of the clavicle at its junction with the insertion of the trapezius muscle; the needle was directed downwards and backwardx The suprascapular nerve was identified by its response to nerve stimulation. Three ml of 0.25% bupivacaine with 1:200 000 adrenaline was injected. The block was repeated twice weekly for a total of 2-4 treatments. Evaluation of the eficacy of the block was achieved by comparing subjective pain scores and passive range of movement before the first block and after the final one. Highly signiJicant improvements were obtained. The choice of blockade of the suprascapular nerve is a new concept for the management of the frozen shoulder of reflex sympathetic dystrophy. This is based on the fact that the nerve contains a high proportion of sympatheticfibres supplying the shoulder joint. The new approach proved to be simple, highly successful, and reproducible. Key words Anatomy; nerve, suprascapular. Anaesthetic technique; regional, suprascapular nerve. Complications; reflex sympathetic dystrophy.
The term 'frozen shoulder' is used to describe a painful stiffness of the shoulder joint characterised by limitation of movement. Various aetiological factors could give rise to this condition including the shoulder-hand syndrome of reflex sympathetic dystrophy (RSD) [I]. Clinically, the frozen shoulder may be the only presenting sign of RSD or it may be associated with hand involvement. A sizeable proportion of frozen shoulder cases have been found following myocardial infarction, hemiplegia and other disorders [2]. The management of the frozen shoulder associated with RSD includes physiotherapy and sympathetic blockade in the form of stellate ganglion or brachial plexus block [3]. Shoulder pain, in general, can be alleviated by suprascapular nerve block [4]. The technique of suprascapular nerve blockade, as described in textbooks, involves a posterior approach, the needle entering above the scapula [S]. Since sympathetic fibres supplying the shoulder joint run in the suprascapular nerve, it is conceivable that sympathetic blockade to the shoulder could be achieved at the level of this nerve. The aim of this study was to present a new and simple approach to the suprascapular nerve, whereby the needle is inserted via an anterior approach above the clavicle, and
to evaluate its efficacy in the management of the frozen shoulder of reflex sympathetic dystrophy.
Methods Institutional approval was given for the study and informed consenting patients with the diagnosis of frozen shoulder associated with reflex sympathetic dystrophy were referred for pain relief management. All patients complained of diffuse dull pain, tenderness and variable swelling of the affected shoulder joint, and limitation in range of passive movement. The case history of the frozen shoulder was reviewed for each patient. Demographic data obtained included age, sex, duration of shoulder pain and disability and presumed aetiology. Symptoms were graded according to severity of the pain; grade 1: severe, grade 2: moderate and grade 3: mild. The patient evaluation consisted of the following: (a) objective joint pain score: this was obtained by palpation of the glenohumeral joint and scored as follows: 0 = no pain, 1 = mild pain to deep palpation, 2 = severe pain to deep palpation, 3 = severe pain to mild palpation and 4 = hyperaesthesia. (b) passive range of movement score (PROM): this was determined as follows: ( I ) ability to elevate the arm through 180",
M.R. Wassef, MB, BCh, DA, FFARCS, Assistant Professor of Anesthesiology, Mount Sinai School of Medicine, New York, USA. Presented in part to the Eighth European Congress of Anaesthesiology, September, 1990, Warsaw, Poland. Accepted 3 June 1991. 0003-2409/92/020120 +05 $03.00/0
@ 1992 The Association of Anaesthetists of Gt Britain and Ireland
120
Suprascapular nerve block
Trapezius
\
121
through the suprascapular notch and enters the supraspinous fossa, where it gives off several branches including articular branches to the acromioclavicular and the shoulder joints. It then runs deep to the supraspinatus muscle and curves round the lateral border of the spine of the scapula to gain the infraspinous fossa where it gives off more branches including articular filaments to the shoulder joint. The coracoid process arises from the upper border of the head of the scapula and is bent sharply so as to project forwards and slightly laterally. Its medial margin is almost aligned with the suprascapular notch, and its tip can be felt through the skin [6].
Lotera I deltoid
Fig. 1. A lateral view of the shoulder depicting the point of needle entry, marked X, at the junction of the trapezius muscle and the clavicle.
(2) ability to elevate the arm above the horizontal level, (3) ability to elevate the arm to the horizontal level, (4) ability to elevate the arm to below the horizontal level and (5) inability to move the arm. Active range of movement was not measured in this study since most of the patients had CNS-related conditions. (c) Visual analogue score (VAS): the patient was asked to mark a 100 mm scale where 0 indicated no pain and 100 indicated extreme severe pain. These tests were carried out prior to the first block and after the final one. Anatomy
The suprascapular nerve is a large nerve which arises from the upper trunk of the brachial plexus. It runs laterally, posteriorly and inferiorly deep to the omohyoid and trapezius muscles, but superficial to the brachial plexus, to reach the superior border of the scapula. Here it passes
Technique
The patient is placed in the sitting position. The landmarks used are the coracoid process, the trapezius muscle and the clavicle. The point of entry of the needle is marked at the junction of the medial border of the trapezius muscle and the posterior border of the lateral third of the clavicle (Fig. I). This point is above the clavicle, and lies at the apex of a triangle set in the perpendicular plane whose base is a line formed by the medial side of the tip of the coracoid process anteriorly and the suprascapular notch posteriorly (Fig. 2). Under aseptic conditions a 22 gauge needle was inserted and directed backwards and downwards with slight medial inclination, along the posterior side of the triangle. A peripheral nerve stimulator was employed for identification of the suprascapular nerve. Nerve blockade was produced by injection of 3.0 ml of 0.25% bupivacaine with 1:200000 adrenaline. All blocks proved to be uneventful. The block was repeated twice weekly. The total number of blocks for each patient varied according to the diminution of pain and improvement in the passive range of shoulder movement. During and after suprascapular nerve block therapy, patients were maintained on a physiotherapy programme.
Fig. 2. Superior view of the shoulder depicting the suprascapular nerve in relation to the clavicle and the coracoid process.
122
M . R . Wassef
Fig. 3. Objective joint pain score before and after the suprascapular nerve block therapy. 20.0
40.0
60.0
80.0
100.0
Visuol onologue scale (rnrn)
Analysis of data Data of various parameters were calculated as mean (SD). Comparison between the parametric variables were performed using Student’s t-test. Statistical significance was considered at a level of p < 0.05.
Fig. 5. Correlation between the visual analogue scale and the passive range of movement, before and after the suprascapular nerve block therapy. Y = 1.052+0.039X; r = 0.986; p < 0.001.
blocks performed was 3.22 (SD 0.4) (range 2-4). Depth of needle insertion was 3.90 (SD 0.19) cm (range 3-5 cm).
Results Frozen shoulder characteristics
Patient characteristics Nine patients with the frozen shoulder of RSD received suprascapular nerve block therapy. Their mean age was 60.33 (SD 5.41) years (range 32-76) and all were female. The precipitating aetiological factors were mainly central nervous system pathology resulting in paraplegia in five patients, cervical cord injury in one, brachial plexus injury in one patient and trauma in two patients. The mean time between the development of symptoms and evaluation was 9.56 (SD 1.09) months (range 2-12). The mean number of
All patients presented with the shoulder component of RSD affecting one side only. The chief complaint was shoulder pain and restricted active movement in the nonparaplegic patients. Symptom grades were: grade 1 (severe) in three patients and grade 2 (moderate) in six patients. The presenting sensory phenomena associated with pain were hyperaesthesia in all patients (100Y0)and hyperalgesia in six. The subjective description of pain in grade 1 patients ( n = 3) was burning in one and lancing in two while in all grade 2 patients (n = 6) it was dull and aching. Pain scores
Preblocks
Postblocks
Fig. 4. Visual analogue scale (VAS) before and after the suprascapular nerve block therapy.
There was a significant decrease in the mean objective joint pain score indicating improvement in the patient’s tolerance to deep pressure applied to the shoulder joint. Overall scores before and after the block therapy were 3.1 1 (SD 0.11) and 0.56 (SD 0.18) respectively, p < 0.001, (Fig. 3). There was a significant decrease in the visual analogue scores (VAS) indicating the patient’s appreciation of pain alleviation. Mean scores before and after the block therapy were 85.56 (SD 2.94) and 12.78 (SD 3.55) respectively, p < 0.001. The mean percentage of improvement was 86.00 (SD 3.72) (Fig. 4). A highly significant correlation was found between the visual analogue score and the passive range of movement obtained before and after the blocks r = 0.986, p < 0.001. The regression equation calculated was; Y = 1.052 + 0.039 X,where Y is the passive range of movement score, and X is the visual analogue score in mm (Fig. 5). A significant improvement was obtained in the passive range of movement (PROM) score. The mean scores before
Suprascapular nerve block 5.0
4.0
3.0
? 8 cn 2.0
1.0
Preblocks
Postblocks
Fig. 6. Passive range of movement (PROM) score of the shoulder before and after the suprascapular nerve block therapy.
and after the block therapy were 4.33 (SD 0.50) and 1.56 (SD 0.18) respectively p < 0.001, (Fig. 6). Discussion
The frozen shoulder is frequently described as either the sole presenting manifestation or a component of the shoulder-hand syndrome of reflex sympathetic dystrophy (RSD) [I]. Two common aetiological factors are associated
123
with this disease, namely myocardial infarction and hemiplegia, although other factors such as trauma could predispose. The relationship between hemiplegia and the signs and symptoms of the shoulder-hand syndrome was emphasised by deTakats [7] and Evans [8]. In posthemiplegic shoulder-hand syndrome patients the pain and restricted movement disappears with sympathetic blockade [9], in conjunction with a programme of physiotherapy. Suprascapular nerve block is said to be useful in the management of severe painful conditions of the shoulder joint, but there is little reference to the use of suprascapular nerve block for the management of pain in the frozen shoulder of RSD. The present work showed that the anterior approach to blockade of the suprascapular nerve produced a highly significant reduction of pain and improved passive range of movement in the frozen shoulder of RSD. There were two aims behind this work: to present a new approach to blockade of the suprascapular nerve, and to demonstrate the efficacy of this block in the management of the frozen shoulder of RSD. The anterior approach is of particular value with bedridden patients as it can be performed while the patient is lying in bed. All that is required is exposure of the front part of the shoulder and neck. The traditional posterior approach requires turning and positioning; a strenuous task for the nursing staff as well as for the patient. The anterior approach proved to provide an easy and reproducible access to the suprascapular nerve. Suprascapular nerve block produces sympathetic blockade similar to that obtained with stellate ganglion
Fig. 7. X ray of the shoulder area after injection of local anaesthetic mixed with radio-opaque material
124
M .R . Wassef
blockade but spares the patient from the inherent risks of the latter technique [lo]. The most serious complication of the traditional approach to suprascapular nerve blockade is pneumothorax; the incidence is reported to be less than one percent [I I]. This can occur if the needle is passed above the upper border of the scapula and advanced too far anteriorly, piercing the lungs. It is highly unlikely for this complication to occur with the anterior approach, since the needle is directed posteriorly and from a higher angle. Also, the point of needle entry is away from the dome of the lung and its direction is in a plane which is perpendicular t o the ribs. This makes penetration of the intercostal space highly unlikely. Figure 7 is an X ray showing the needle away from the thoracic cage. The needle tip is superficial to the suprascapular notch, showing that the suprascapular nerve can be blocked a t a superficial level and before it reaches the suprascapular foramen. A number of hypotheses have been proposed concerning the mechanism of reflex sympathetic dystrophy [12, 131. Roberts [ 141 suggested that trauma initially activates unmyelinated C-nociceptors, which in turn activate and sensitise wide dynamic range (WDR) neurones in the dorsal horn whose axons ascend to higher centres. This sensitisation persists, so that the WDR neurones now respond to activity in large-diameter A-mechanoreceptive low threshold afferents, which are activated by light touch or brushing. Moreover, these sensitised WDR neurones respond to A-mechanoreceptive activity initiated by sympathetic efferent action on sensory receptors in the absence of cutaneous stimulation and thus produce spontaneous pain or what Roberts calls ‘sympathetically mediated pain’. Nathan [IS]has used the abnormal state of the dorsal horn as an explanation for RSD caused not only by limb injury but also by central nervous system pathology. In conclusion, sympathetic blockade at the level of the suprascapular nerve for the management of the frozen shoulder of RSD proved to be a highly specific procedure,
in terms of sympathetically mediated shoulder pain. The anterior approach to the suprascapular nerve is a new, simple, convenient and reproducible technique offering easy accessibility to the suprascapular nerve in the bedridden patient, as opposed to the traditional posterior approach.
References [I] STEINBROCKER 0. The shoulder hand syndrome. Americun Journal of Medicine 1947; 3: 402-7. 0, ARGYROSTG. The shoulder-hand [2] STEINBROCKER syndrome: present status as a diagnostic and therapeutic entity. Medical Clinics of North America 1958; 4 5 15. BONICAJJ. BUCKLEY FP. Regional analgesia - with local anesthetics. In: BONICAJJ, ed. The managemenf of pain. Philadelphia: Lea & Febiger, 1990: 1933, 1904. BONICAJJ, CAILLET R. General considerations of pain in the JJ, ed. The management of neck and upper limb. In: BONICA pain. Philadelphia: Lea & Febiger, 1990: 826. ERIKSONE. Illustrated handbook in regional anaesthesia, Copenhagen: Munksgaard, 1969: 81. GRAYH. Anatomy; descriptive and applied, 30th edn. London: Longmans, Green and Co, 1949: 1123-4, 343. DE TAKATS G. Causalgic states in peace and war. Journal of the American Medical Association 1945; 128: 699-740. EVANSJA. Reflex sympathetic dystrophy. Surgical Clinics of North America 1946; 2: 780-90. PW, SCOTTGD. Pain due to lesions of the LOHL, NATHAN central nervous system removed by sympathetic block. British Medical Journal 1981; 282 1026-8. COUSINS,MJ, BRIDENBAUGH, PO. eds. Neural blockade in clinical anesthesia and management of pain. Philadelphia: Lippincott, 1980: 539, 549. MOOREDC. Regional block, 4th edn. Springfield: Thomas, 1965: 300-3. LIVINGSTON WK. Pain mechanisms: a physiologic interpretation of causalgia and its related slates. New York: Macmillan, 1943: 83-127. R. Phantom limb pain: Implications for treatment [I31 MELZACK of pathologic pain. Anesthesiology 1971, 3 5 409-19. [I41 ROBERTS WJ. An hypothesis on the physiological basis for causalgia and related pains. Pain 1986; 2 4 297-31 I . [I51 NATHANPW. Pain and the sympathetic nervous system. Journal of the Autonomic Nervous System 1983; 7: 363-70.
