Acromion splitting approach for extensive exposure of shoulder and proximal humerus

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1 Original Article Acromion splitting approach for extensive exposure of shoulder and proximal humerus Dominic Puthoor 1, Prabhakaran Jayaprakashan 2 Amala Institute of Medical Sciences Thrissur, Kerala India 1 Assoc. Professor & Orthop. Oncologist 2 Asst. Professor of Orthopaedics Correspondence should be sent to: dkputhur@gmail.com Abstract A new approach to shoulder, meant primarily for wide resection of malignant lesions of upper humerus is described. The entire shoulder with rotator cuff and upper humerus is exposed by reflecting the deltoid with its origin as an osteomyocutaneous flap. It is a logical combination of anterior, transacromion and the deltoid spitting incision. The advantages include better visualisation, retaining the blood supply and strength of deltoid, better healing and good reproducibility. The potential disadvantages include loss of nerve supply to the anterior fibers of the deltoid and non union of acromion. Key words: Shoulder, exposure, acromion Kerala Journal of Orthopaedics 2011;24:4-9 Kerala Journal of Orthopaedics Introduction Basic approaches to shoulder are Anterior, Lateral and Posterior. [1,2,3,4] Of these, the anterior approach is the work-horse incision of the shoulder, providing excellent exposure of both the joint and its anterior coverings.[3] But when exposing distally as is usually required for tumours of proximal humerus, the following problems are encountered. 1. Short head of biceps and coracobrachialis along with the musculocutaneous nerve obstruct the view and its prolonged retraction can cause structural damage. Pectoralis major also obstructs the view unless it is detached from its insertion. 2. Anterior approach is extended by subperiosteal dissection of the deltoid or the deltoid is taken off leaving a cuff of soft tissue for later reattachment. 3. Approach is through deltopectoral groove which though desirable for routine orthopedic procedures, is against the basic principles of tumour surgery as it involves two compartments. In addition, deltopectoral groove is not easily visible in obese people and the plane between deltoid and pectoralis major is not clear cut. So splitting the two muscles apart is not that easy. Presence of cephalic vein with its tributaries makes the superficial dissection further difficult.[3,4] Lateral approaches are the Split deltoid approach and the Transacromial approach.[1,2,3,4] Split deltoid approach is through tendinous interval 4 to 5 cm long between the anterior and middle thirds of the deltoid. Splitting the muscle here provides a fairly avascular approach to the lateral part of upper humerus. Thus lateral approach, in comparison with anterior approach gives better exposure of the upper humerus especially its posterior aspect. But it is limited by axillary nerve. The extended anterolateral acromial approach by Gardner and extended deltoid splitting approach by Robinson et al to the proximal humerus are modifications of this lateral approach.[5,6] In both, the zone of 4 Kerala Journal of Orthopaedics Volume 24 Issue 1 July 2011

2 Dominic et al.: Acromion splitting approach for extensive exposure of shoulder and proximal humerus deltoid transversed by the anterior branch of the axillary nerve is identified and protected. This modification though good for fracture fixation, does not give adequate exposure for tumour surgery. Transacromial approach is primarily to expose sub acromial structures like supraspinous tendon by osteotomising acromion. Pattern of osteotomy by different authors vary.[2] Darrach describes an oblique osteotomy while McLaughlin does it in a sagital plane. Armstrong advises complete acromionectomy. Kuz et al. recommended a coronal trans acromial osteotomy just anterior to the spine of the scapula and parallel to it.[2,3,4,7] Again exposure is very limited. The approach we developed is a logical combination of Anterior, Transacromion and Deltoid spitting incision. This is primarily meant for tumour surgery. But we have found it useful in all cases requiring extensive exposure of shoulder and upper humerus like four part fracture dislocation of proximal humerus and shoulder. Original Article Details of exposure Position Place the patient in a supine position on the operating table. Wedge a sandbag under the spine and medial border of the scapula to push the affected side forward while allowing the arm to fall backward, opening up the front of the joint.[3] Incision Upper part of the incision is over the subcutaneous dorsal surface of acromion like the saber cut of the trans aromion approach[2]. It curves a little medially up to the acromio clavicular joint. It then extends inferiorly over the anterior third of deltoid, avoiding the deltopectoral groove, but including the biopsy track (Figure 1). In tumour surgery excision of biopsy track is a must. After the skin incision, in the upper part, go directly on to the acromion. Mark the osteotomy site with cautery. Acromion osteotomised at about angle (Figure 2,3). Materials and methods This approach was used in 19 surgeries done during 1997 to This includes : Osteosarcoma - 8 Chondrosarcoma - 4 Secondaries from Thyroid - 1 Giant Cell tumour - 2 Chondroblastoma - 2 Four part fracture disloc. of proximal humerus - 2 Figure 2. The site of acromion osteotomy is shown as straight lines Figure 1. Incision. Upper part is sabercut. Inferiorly it goes medial to deltopectoral groove encircling the biopsy track Figure. 3. The acromion is being slit Kerala Journal Of Orthopaedics Volume 24 Issue 1 July

3 Original Article Dominic et al.: Acromion splitting approach for extensive exposure of shoulder and proximal humerus Distally dissection proceeds, splitting fibers of deltoid which are parallel in its anterior third. Middle deltoid with its multipennate arrangement is kept intact and remains attached to the bone.[8,9,10] (Figure 4). (In non tumour conditions like fracture dislocation, we go through the deltopectoral groove). Entire osteomyofasiocutaneous flap is reflected down like peeling skin of a banana (F igure 5,6). Tumor bearing proximal humerus is exposed on all sides. Tumor excision starts by osteotomising shaft of humerus at the previously determined site with the help of MRI. As the specimen is elevated from its bed, look for the axillary nerve and the posterior circumflex vessels emerging from the quadrangular space. We have managed to save the axillary nerve in majority of our cases (Figure 7). Excision is usually completed by incising the capsule of shoulder joint all around, close to the glenoid. If there is intra articular extension, osteotomy though the glenoid completes the excision. Reconstruction of bone defect Bone reconstruction is either by osteosynthesis with upper end of fibula or by prosthetic replacement. In 4 cases of osteosarcoma and 2 cases of chondrosarcoma and one case of GCT, free fibula graft is used. In 4 cases of Figure 4. Arrangement of fibers in deltoid. Plan of the approach is shown as red lines Figure. 5. Exposure of tumour bearing bone and rotator cuff Figure 6. Reflecting osteomyofasiocutaneous flap is like peeling skin of banana 6 Kerala Journal of Orthopaedics Volume 24 Issue 1 July 2011

4 Dominic et al.: Acromion splitting approach for extensive exposure of shoulder and proximal humerus Figure 7. Shows the axillary nerve and posterior circumflex artery which is always saved. Original Article Figure 8. Reconstruction of the rotator cuff osteosarcoma and one case of chondrosarcoma, custom made prosthesis was used. All four part fracture dislocations and the case of secondaries from thyroid and one case of chondrosarcoma was reconstructed by Neer s prosthesis. In the last two cases, prosthesis was augmented by bone cement. In two cases of chondroblastoma and one case of GCT, curettage and bone grafting was done. Soft tissue reconstruction Reconstruction of rotator cuff is done as follows. Non absorbable sutures anchored to infraspinatus and subscapularis were tied around the neck of fibula. Supraspinatus is tied to the long head of biceps (Figure 8). Repair of the acromion It was done using stainless steel wire in first 4 cases. Later we switched on to Ethibond No.5. Suture passes though trapezius muscle just medial to the intact portion of acromion. It then passes deep to acromion then deep to detached portion of acromion and emerges out though deltoid (Figure 8). This results in anatomical restoration of acromion and contour of the shoulder. No attempt was done to fix the fragment with screws or wires. Post operative treatment After surgery arm to chest strapping was given. Elbow and hand movements are encouraged immediately. Wound was inspected on 3 rd day. Arm to chest strapping and sutures were removed on 10 th day and arm was supported in a pouch arm sling. External rotation movements were started after 2 weeks. Abduction was allowed only after 6 weeks. Results In all cases wound healed well and there were no infections. In the initial 4 cases where we used stainless steel wire, it was palpable under the skin. In one case it was removed 6 weeks after surgery because of skin irritation. In the post operative X-ray, osteotomised acromion appeared as fragments of bone and there was no evidence of bone union in X-ray after one year. Clinically there was no abnormal movements of the fragments on attempted contraction of deltoid indicating sound fibrous union of the fragments of acromion. No patient complained of pain over the site of acromion osteotomy. Stability of shoulder and range of movements depended on extent of resection and age of the patient. Cases where curettage was done regained excellent function when functional status was determined at final follow up at 2 yrs using Musculoskeletal Tumor Society Scoring System. In case of fracture dislocation, where age was 64 and 70 respectively, there was restriction movement (abduction 30 0 & external rotation 25 0 in both cases). Both of them had excellent stability of the shoulder so that with the help of scapulothoracic movements they were able to carry out all activities of daily living. Rest of the cases were aggressive lesions in which variable portions of rotator cuff and joint Kerala Journal Of Orthopaedics Volume 24 Issue 1 July

5 Original Article Dominic et al.: Acromion splitting approach for extensive exposure of shoulder and proximal humerus capsule were sacrificed. All of them have varying degrees of instability, markedly impairing shoulder function. Still all cases managed to reach the hand up to the mouth, 5 cases of osteosarcoma and 2 cases of chondrosarcoma had either local recurrence requiring forequarter amputation or developed pulmonary metastasis within 2 years of index surgery. Of the remaining, 7 cases had good results. They can actively position the hand, up to the forehead, have excellent function of wrist and hand and can lift light objects and place them unassisted. Rest of the cases have fair or poor results due to problems of prosthesis, like loosening or due to problems of grafted bone, like nonunion of fibula to host bone. But they are not related to the approach or non union of acromion. Discussion What are the factors that inspired us to think of a different approach? Routine exposures necessitate taking off the origin of the deltoid. In cases of extensive tumors, the insertion may also need to be sacrificed. In such cases the deltoid turned a shade black on table itself. Expectedly, deltoid fails to function. Muscle to bone healing is predictably insufficient with risk of pull out. The first author had started developing this approach since The approach has gone through many modifications over the years to its present dimension. The lateral border of acromion, which is thick and irregular gives origin to middle or intermediate fibers of deltoid with multipinnate arrangement. [8,9,10] Here the muscle fibers are numerous and short. On this account it is very powerful though the range of movement is short. In our approach this unit remains undisturbed along with its origin. In contrast, anterior and posterior parts are composed of long parallel fibers which can be dissected out without loss of strength. Our osteotomy does not disturb the integrity of the acromion or the acromioclavicular joint. The osteotomy will come between the area supplied by acromial branch of thoracoacromial and subscapular arteries which supply the medial portion of acromion and ascending branch of posterior circumflex humeral artery which supply the lateral aspect of acromion. So blood supply remains uninjured. There are two muscular coverings or sleeves over the shoulder joint. The outer sleeve is the deltoid muscle. The inner sleeve is the rotator cuff.[2] In our approach, we are reflecting the outer sleeve with its attachment like the peeling the skin of a banana. In this aspect it is like the posterior exposure of elbow and distal humerus by Olecranon osteotomy described by Muller ME, Mac Ausland WR.[12] Muscles, not bone and joints, serve as the primary mechanism for securing the shoulder girdle to the rest of body.[13] That is the rationale behind osteotomising acromion rather than detaching the deltoid muscle. That is why even in traumatic fractures, non union of acromion produces no significant functional disability. After reconstruction of split acromion, no bony union occurs. Instead it results in stable painless fibrous union with no functional deficit.[14,15,16] J.E.Kuhn et al. who proposed a classification system of fractures of acromion process found that most nonunion that occurred with traumatic acromion fractures were not painful.[14] They also feel that acromion fractures do not require anatomical reduction even when it is displaced unless it produces reduction of the subacromial space. Other authors also feel non operative treatment is good enough for most of acromion fractures.[15,16] Advantages of our approach It retains the blood supply and strength of deltoid. For tumor clearance, we have to remove the insertion of deltoid which makes it totally avascular, if detached from the origin. It is practically impossible to get lost with this approach unlike the anterior approach,[4] because the acromion is subcutaneous over its dorsal surface, being covered only by skin and superficial fascia;10] making it easily palpable. Field is better visualised and structures are easily identified. Healing is better. Of all the connective tissues in the body, bone has the maximum healing potential. Acromion with its fibrous union become broader and it gives better support for the new shoulder joint formed by the head of fibula and glenoid. Finally, the approach is easily reproducibile. Disadvantages 8 Kerala Journal of Orthopaedics Volume 24 Issue 1 July 2011

6 1. Non union of acromion References 1. Surgical approaches to the shoulder joint. Lenoy C. Abbot,John Bdec, M.Saunders, Helen H and Ellis W.J. J.Bone Joint Surg Am. 1949;31: Canale & Beaty: Campbell s Operative Orthopaedics, 11th ed Mosby,p Hoppenfeld S. Piet deboer surgical approaches in orthopedics: An Anatomic Edition p1-56 approach 3rd 4. Atlas of Orthopaedic Surgical Exposures. Jordan C Mirzabeigi E.1 st edition Thieme New York. Stuttgart page3-13 Dominic et al.: Acromion splitting approach for extensive exposure of shoulder and proximal humerus 2. Few muscle fibers in the most anterior portion of Deltoid lose its nerve supply. We got only 7 cases with good results. This is not because of the problems of approach, but because of tumour related and prosthesis /graft related complications. In comparison with results of wide excision around knee, the results of malignant shoulder lesions are poor. Summary We recommend this approach for cases which require adequate exposure of the proximal humerus. Advantages include deltoid with intact nerve supply and blood supply, resulting in reasonable function of shoulder. This is especially useful in tumor surgery, where adequate exposure is of prime importance. 5. The Extended Anterolateral Acromial Approach Allows Minimally Invasive Access to the proximal Humerus. Gardner MJ,Griffith MH, Dines JS. Clin Orthop. vol. 434, ,2005 Original Article 6. Robinson CM.,Khan L.Akhtar S.Whittaker R. Extended Deltoid-splitting Appoach to the Proximal Humerus. Orthop Trauma.2007 Vol.21 No.9 7. Kuz JE, Pierce TD, Braunohler WB: Coronal transacromial osteotomy surgical approach shoulder arthroplasty. Orthopedics 1998; 21: Grant s Atlas of Anatomy James E Anderson 7 th Edition 1978 William & Wilkin Co. p John VB Grant s method of anatomy 9 th ed The Williams & Wilkins Company.p Gray s Anatomy 40 th edition Churchill Livingstone Elsevier international edition ISBN Editor in chief- Susan Standing p Axillary artery and anaesthemosis around scapula. Atlas of Human Anatomy.4 th Edition Frankh Netter.M D Saunders Elseviers International Edition ISBN-B: Plate AO principle of fracture management.ruedi T.P.,Murphy M.W. AO Publishing, Switzerland p Joint structure and function. A comprehensive analysis 3 rd edition Pamela K Levangil. Cynthia C. Norkin published by Jaypee Brothers 2001 p Kuhn JE,Blasier RB,Carpenter JE: Fracture of the Acromion Process: A Proposed Classification System. Journal of orthopedic trauma 1994 Vol.8,No 1,pp Mick CA,Weiland AJ, Pseudarthrosis of Fracture of the Acromion. Journal of Trauma 1983 Vol.23,No.3 pp248, Mencke JB.: The frequency and significance of injuries to the acromion process. Ann.Surg.,59; ,1914 for Source of funding : Nil; Conflict of interest : Nil Cite this article as: Dominic Puthoor, Prabhakaran Jayaprakashan. Acromion splitting approach for extensive exposure of shoulder and proximal humerus. Kerala Journal of Orthopaedics 2011;24:4-9 Kerala Journal Of Orthopaedics Volume 24 Issue 1 July