Acta of Shoulder and Elbow Surgery | Volume 2 | Issue 1 | Jan-June 2017 | Page 3-6 | Niso Eduardo Balsini, Olinto Lago Junior

Authors: Niso Eduardo Balsini [1], Olinto Lago Junior [1]

[1] NAEON-Santa Catarina Hospital.
[2] IFOR Hospital.

Address of Correspondence
Dr. Jose Carlos Garcia Jr., MD, MSc, PhD
NÆON-Hospital Santa Catarina-SP-Brazil
Email: jose.cjunior@hsl.org.br

Abstract

Better knowledge of lesion patterns together with advances in surgical devices and techniques have allowed the arthroscopic repair of large rotator cuff tears. However, there are still challenging situations such as chronic retracted degenerated cuff tears whose results of primary anatomic repair attempts are uncertain and unsatisfactory. Many of these tears are considered irreparable.
Recently, extracellular matrix scaffolds and tendon grafts have presented good results in the management of these “irreparable” tears.
In order to evaluate preliminary results of fascia lata autograft for treating complex irreparable rotator tears, five patients were operated and folowed by a mean of twelve months. Outcomes were measured using the UCLA, Visual Analogical Score for pain (VAS) and Constant scores. Results demonstrated fascia lata technique is useful to treat irreparable rotator cuff tears rendering significant functional improvement for patients.
Keywords: Arthroscopy, fascia lata, autologous tendon graft, massive rotator cuff tears.

Introduction

Rotator cuff tear is an important cause of shoulder pain and disfunction. It affects about 40% of the United States population over 60 years-old requiring 30,000 to 75,000 rotator cuff repairs annually [1,2].
The rotator cuff tear is an important cause of shoulder pain and functional limitation. It affects approximately 40% of patients over 60 years old in the United States and between 30,000 to 75,000 rotator cuff repairs are performed annually [1,2].
Better knowledge of lesion patterns together with advances in surgical devices and techniques have allowed an overall tendon healing of 80% for smaller tears. On the other hand, large and massive tears are still a challenge for orthopedic surgeons. Their healing rates are lower than 30% [3].
To reduce failure of massive tears repairs, adjuvant grafts like synthetic dermal grafts, extracellular matrix scaffolds and fascia lata autografts have been proposed [4,5].
The purpose of this study is to evaluate preliminary results of arthroscopic treatment of massive irreparable rotator cuff tears using an autologous fascia lata graft to fill the cuff-to-bone gap.

Methods

Inclusion and Exclusion Criterea
Patients whose MRI presented supraspinatus and/or infraspinatus tears greater than 3 cm in medial-lateral or antero-posterior diameters and muscle fat degeneration stages III or IV of Goutallier-Fuchs [6] classification were considered potential irreparable tears. They were advised pre-operativelly about the possibility of requiring a fascia lata autograft in case a tension-free tendon-to-bone reattachment cannot be achieved using conventional cuff repair techniques. Thus, at the time of surgery the ipsilateral thigh was also prepared with asepsis and antisepsis for this purpose.
Inclusion criteria were: (1) Patte’s medial-to-lateral retraction grade 3 [7]; (2) Goutallier-Fuchs supraspinatus and/or infraspinatus fat degeneration stages III or IV; (3) Teres Minor intact (negative Horner Test); and (4) intraoperative gap preventing cuff-to-bone attachment.
Exclusion criteria: (1) Goutallier-Fuchs stages I and II; (2) Neurologic impairment; (3) Irreparable subscapularis tears; (4) Rotator cuff arthropathy greater than stage 2 of Seebauer classification [8].

Patient evaluation
All patients were evaluated pre- and post-operativelly using visual analisys score (VAS), UCLA and Constant scores one month before and six months after the surgery. Active range of movement (ROM) and painless ROM were evaluated for anterior elevation, external rotation and internal rotation comparing to contralateral side. A digital dynamometer was used to measure shoulder elevation strengh in orthostatic position with arm positioned at 90º of abduction in the scapular plane, elbow extended and forearm pronated. Measurement was performed 3 times and average was recorded. Data related to Constant score compared both sides and the difference of values was defined as excellent (<11); good (11 to 20); fair (21 to 30); and poor (>30 points).

MRI evaluation
The degree of fatty infiltration of supraspinatus, infraspinatus and subscapularis was graded analysing sagittal MRI cuts using the Goutallier classification adapted for MRI by Fuchs. Muscle degeneration was graded using the most lateral T1 image in which spine of scapula was seen in contact with its body (scapular Y view). According to Goutallier-Fuchs [6,9], a five-stage classification was used: no fat infiltration (stage 0); occasional lines of fat between muscle fibers (stage 1); significant amount of fat, but fat-muscle ratio lower than 50% (stage 2); fat-muscle ratio of 50% (stage 3); fat-muscle ratio higher than 50% (stage 4).
Cuff retraction was graded according to Patte classification: retraction at the level of greater tuberosity (grade 1); retraction at the level of humeral head (grade2); retraction at glenoid level (grade 3).
Cuff and graft healing and re-rupture were evaluated by MRI according to criterea well stablished in literature [10, 11, 12]. Complete tears in repaired cuffs were diagnosed when presence of high-intensity signal or tendon-to-bone gap on two or more consecutive T2-weighted cuts. Grafts were evaluated based on their appearance compared to rotator cuff remains at tendon-graft interface and at humeral head footprint. Intact grafts showed absence of high intensity signal at areas of native rotator cuff, tendon-graft and humeral head-graft interfaces. Not-intact grafts showed high intensity signal that these interfaces.

Operative Technique and Fascia Lata autograft usage decision during surgery
With patient in lateral decubitus under general anesthesia and traction on arm, camera was introduced on posterior portal to evaluate the glenohumeral joint. At this stage, subscapularis tendon was evaluated and repaired if necessary. Also, long head of biceps was evaluated for instability or degeneration and if positive, a tenotomy or tenodesis were performed.
After that, the scope was taken to subacromial space and bursectomy was performed. Rotator cuff tear was identified and classified according to shape (L, inverted L, U or C), length and retraction (width) using a calibrated ‘probe’. Tears greater than 5 cm in length or width were classified as massive. If between 3 and 5 cm, they are graded as large [6].
The cuff repair was always tried aiming a tension-free tendon-to-bone attachment. Capsular release, rotator interval sliding and tendon-to-tendon stitches were used when necessary. If even after that, there was still a gap between the tendon and the greater tuberosity, the tear was considered irreparable and fascia lata autograft was used to fill in the gap.

Fascia lata autograft removal from ipsilateral thigh
The fascia lata autograft was removed from ipsilateral thigh using a lateral incision 10 cm above knee joint line. (Figure 1). To avoid insufficient graft tissue, we always oversized 5 mm in addition to gap length and width. Finally, edges of graft were tied with a continuous PDS 5.0 suture (figure 2).

Graft placement and tendon-to-graft repair
Usually five portal were used to tendon-to-graft suture: posterior, anterolateral, lateral, lateral accessory and Neviaser. If necessary other portals may be used to reach a better angle for anchor insertion, sutures placement or adhesion releases.
Cannulas were introduced on posterior, anterolateral and lateral portals. Two No.2 Ethibond threads were placed at supraspinatus edge through Neviaser portal. One thread at infraspinatus through posterior portal. Moreover, another thread at rotator interval through anterolateral portal. All four threads were taken to the lateral cannula to be stitched to the fascia lata graft. Afterwards, each thread was repositioned to its respective portal.
Introducting the graft onto subacromial space was always a delicate step, which requires progressive traction to threads and concomitant assistance to pass the graft through the lateral cannula avoiding folding or twist. In this way, the graft was strained open in the subacromial space with the use of a probe and knots were performed is the following sequence (figure 4): first two knots on the supraspinatus; then the one on infraspinatus; and finally the rotator interval knot.
At last, two or three suture anchors were placed on greater tuberosity to attach the graft to bone with ‘Revo” simple knots.

Post-operative care
All patients were immobilized with a sling for 60 days. At fourth month postoperatively, a MRI was done to evaluate healing and positioning of the graft (figure 5).

Results

From January to June 2016, eight patients received the fascia lata grafting for irreparable rotator cuff tears. Three patients were male and two females. They were followed up for an average of nine months post-operatively (6 to 18 months). Average age was 67 year-old (49 to 80 range). According to Goutallier-Fuchs, five patients were classified as stage III and three stage IV. All patients were Patte’s grade III. Four cases were failured repairs and four were primary surgeries. Three cases required subscapularis repair and biceps tenotomy was performed in four cases and one biceps tenodesis was performed (Table 1).

Functional scores
VAS pre-operatively was 7.87±0.55 and decresed to 1.25±0,37 points post-operatively (P<0.001) (Table 2) . The Constant score raised from 34.38±2.73 to 85.00±1.73 (P<0.001) (Table 3). In addition, UCLA score improved from 10.50±1.82 to 32±0.48 (P<0.001) (Table 4).
All curves passed in the DAgostino & Person normality test. Statistical analysis was performed by using the Student’s T test. Scores improvement was as follows in Table 5.

MRI evaluation
All eight cases repeated MRI after 16 weeks of surgery. Seven patients presented continuity of tendon fibers-to-graft and graft-to-bone suggesting complete graft healing. One case presented a hypersignal on graft-to-bone interface at one coronal slice, which suggests incomplete integration of graft to bone. However, other slices had normal graft-tendon interface signals and patient had satisfactory functional scores. So, seven cases were considered to have complete healing and one partial healing.

Complications
There was one case of hematoma at the donor site for fascia lata graft that resolved spontaneously. Another patient had a frozen shoulder that evolved to complete ROM afetr six serial suprascapular nerve blocks.

Discussion

A reason for difficult treatment of massive rotator cuff tears is that pathogenesis of these lesions has not been fully clarified yet. Besides, rotator cuff has limited healing capacity at its humeral insertion. To overcome these limitations, new techniques have been proposed, like improving biomechanics with double-row repairs, biological enhancements using growth factors, cytokines, platelet-rich plasma (PRP), tendon grafting, extracellular scaffolds, gene therapy and tissue engineering on mesechymal cells 1.
Nowadays, extracellular matrix derivative scaffolds, polyurethane-urea and poly-L-lactic (PLLA) are commercially available and FDA approved to enhance rotator cuff repairs in humans. Their aim is to serve as a patch attached to the cuff supporting cell ingrowth over it [1]. Several studies have demonstrated pain reduction, improved daily live activities, satisfaction and cuff stregth increase with these scaffolds compared to pre-operative conditions [1,2].
Other option available is the human dermal matrix allograft for tendon augmentation. The allograft is processed and become acellular, which reduces immunogenic response, while extracellular collagen matrix remains intact and provide strength and support to tissue ingrowth [2].
The muscle fascia has similar structural and biochemical properties of a healthy tendon, but it has poor suture retention properties (10N), which limits its utility as a scaffold for rotator cuff repairs [1]. An alternative solution is to reinforce fascia with a PLLA polymer. Studies have showed that this technique may improve suture retention properties and decrease cyclic retraction gaps, turning it comparable to a human tendon. Soon, there will be reinforced fascias that will provide the necessary mechanical strength to enhance rotator cuff repairs, minimizing retractions and reducing rapair failures [1].
Fascia lata autografts are consolidated techniques widely used in many areas of medicine like plastic surgery, neurosurgey, urology, orthopedics and ophthalmology. Complex cases head trauma with extensive loss of the scalp have shown good results using fascia lata grafts [13]. Barbosa et al used the fascia lata tensor muscle for operative wound complications in patients with genital neoplasia and severe inguinal defects, reporting that the graft is an important tool for reconstructing the inguinal ligament [14]. Sebastiá et al showed that fascia lata graft reduces incidence of complications in reconstructions of anophthalmic cavity with inclusion of implants coated with this graft [15]. Bayat et al used a fascia lata graft in an alpinist to reconstruct bilateral chronic retracted distal biceps rupture. Results were satisfactory regarding the supination and flexion strength of the elbow16.
Mori et al [17]compared 24 patients who underwent partial repair for massive irreparable rotator cuff tears to 24 patients with similar tears that underwent fascia lata graft to fill the gap. The recurrence rate in the partial repair group was 41.7% while in the fascia late group it was 8.1%. The technique described in this article differs from Mori’s technique in graft removal and in the preparation of the graft. Mori removes the graft from proximal thigh, close to the greater trochanter, while we remove fascia lata at a distal thigh site close to the knee. In addition, we have created a double graft by removing a larger graft size and folding it by half, while Mori uses a single leaf graft.
McCarron et al [5] evaluated the biomechanical properties of the fascia lata graft on 18 cadavers with 5 cm irreparable rotator cuff tear created by disinsertion of supraspinatus from the proximal humerus. In half of cases, the cuff was reattached using suture anchors only, while the other half received suture anchors and fascia lata grafts. All shoulders were subjected to a thousand cycles of 180N loading. Results showed the group with fascia lata reinforcement presented gaps along suture line 40% smaller than the group without it, suggesting that fascia lata minimizes tendon retraction and thereby decreases incidence of cuff repair failure [5].
Baker et al [4] in an amimal study compared biomechanical properties of eleven dogs submitted to surgery in both shoulders. In one group, only partial sutures were done and in the other fascia, lata reinforcement was performed. Results showed a significant increase in the loading force of tendon that received the fascia lata graft, suggesting that this technique might bring benefits to humans.
Based on these reports, we decided to use fascia lata autograft to repair complex rotator cuff tears due to small complication rates, low morbidity at donor site, feasible technique and lower surgical cost when compared to synthetic grafts. In addition, our technique follows the biological concept of graft use for orthopedic lesions.
As massive irreparable rotator cuff tears are relatively uncommon lesions, it is difficult to obtain large numbers of patients in order to produce a prospective randomized surgical Trial. So future comparative papers are necessary to prove effectiveness of this procedure. However, it is still a good and cheap option for dealing with chronic irreparable rotator cuff tears in patients younger than 70 years-old.
For the future, we understand there is a great difference between repair and tissue regeneration quality. Facing this undesired dichotomy, we intend to direct our future research to study biological evolution of the fascia lata graft to tendon healing.

Interest conflicts

The authors declare no conflict of interest.

References

1. Maffulli N, Longo UG, Loppini M, Berton A, Spiezia F, Denaro V. Tissue engineering for rotator cuff repair: an evidence-based systematic review. Stem Cells Int.2012; 2012:418086.
2. Bond JL, Dopirak RM, Higgins J, Burns J, Snyder SJ. Arthroscopic replacement of massive, irreparable rotator cuff tears using a GraftJacket allograft: technique and preliminary results. Arthroscopy. 2008;24(4):403-409.e1.
3. Nho SJ, Yadav H, Pensak M, Dodson CC, GoodCR, MacGillivray JD. Biomechanical fixation in arthroscopic rotator cuff repair. Arhroscopy. 2007;23(1):94-102,102.e1.
4. Baker AR, McCarronJA, TanCD, IannottiJP, DerwinKA. Does augmentation with a reinforced fascia patch improve rotator cuff repair outcomes? Clinical Orthop Relat Res. 2012;470(9):2513-21.
5. McCarron JA, Milks RA, Mesiha M, Aurora A, Walker E, Iannotti J P, et al. Reinforced fascia patch limts cycling gapping of rotator cuff repairsin human cadaveric model. J Shoulder Elbow Surg. 2012;21:1680-6.
6. Goutallier D, Postel JM, Bernageau J, Lavau L, Voisin MC. Fatty muscle degeneration cuff ruptures. Pre- and post- operative evaluation by CT scan. Clin Orthop Relat Res 1994;304:78-83.
7. Patte D. Classification of rotator cuff lesions. Clin Orthop Relat Res 1990; 254:81–86
8. Seebauer L. Seebauer. Total reverse shoulder arthroplasty: European Lessons and future trends. Am J Orthop (Belle Mead NJ).,36(12 Suppl 1) (2007),pp.22-28.
9. Fuchs B, Weishaupt D, Zanetti M, Hodler J, Gerber C. Fatty degen- eration of the muscles of the rotator cuff: assessment by computed tomography versus magnetic resonance imaging. J Shoulder Elbow Surg. 1999;8:599-605.
10. Mellado JM, Calmet J, Olona M, et al. Surgically repaired massive rotator cuff tears:MRI of tendon integrity, muscle fatty degeneration, and muscl atrophy correlated with intraoperative and clinical finding. AJR Am J Roentgenol.2005;184(5):1456-1463.
11. Gusmer PB, Potter HG, Donovan WD, O’Brien SJ. MR imaging of the shoulder after rotator cuff repair. AJR Am J Roentgenol. 1997;168(2):559-563.
12. Owen RS, Iannotti JP, Kneeland JB, Dalinka MK, Deren JA, Oleaga L. Shoulder after surgery: MR imaging with surgical validation. Radiology. 1993;186(2):443-447
13. Bazzi K, Formighieri B, Lorico T L, Rocco M, Machado M F, Vilella L. Reconstruções complexas do couro cabeludo: um desafio aos cirurgiões. Rev. Bras. Cir. Plást. 2010; 25(supl): 1-102
14. Barbosa, E. Malheiro, N. Tomada, P. Silva, J. Silva, C. Silva, J. Reis, J. Amarante Acta Urológica 2006, 23; 3: 67-70.
15. Sebastiá Roberto, Lessa , Sergio Lessa, Eduardo Emery Flores. Reconstrução da cavidade anoftálmica com implante esférico revestido de enxerto autólogo de fáscia lata. Rev Bras Oftalmo 59(2):132-143, fev.2000.ilus.
16. A. Bayat, L. Neumann, W.A. Wallace Late repair of simultaneous bilateral distal biceps brachii tendon avulsion with fascia lata graft Br J Sports Med, 33 (4) (1999), pp. 281–283
17. Mori D, Fumakoshi N, Yamashita F. Arthroscopic surgery of irreparable large or massive rotator cuff tears with low-grade fatty degeneration of the infraspinatus: patch autograft procedure versus partial repair procedure. Arthroscopy.2013;29(12):1911-1921.

Niso Eduardo Balsini

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Acta of Shoulder and Elbow Surgery | Volume 2| Issue 1 | Jan-Jun 2017 | Page 36-39| Bijayendra Singh, N Bakti

Authors: Bijayendra Singh [1], N Bakti [1]

[1]Medway NHS Foundation Trust, Visiting Professor Canterbury Christchurch University.

Address of Correspondence
Prof. Bijayendra Singh,
Consultant Orthopaedic Surgeon,
Medway NHS Foundation Trust, Visiting Professor Canterbury Christchurch University, Medway, KENT
Emial:- bijayendrasingh@gmail.com

Abstract

Introduction: The objective of this study is to present a cadaveric study with new possibilities of using the surgical robot in the daily practice of the shoulder surgeon, verifying which structures can be better visualized and manipulated at the posterior side of the shoulder.
Material and methods: Two fresh cadaver shoulders were used. The positioning of the shoulder was as like in a prone decubitus, with an arm in a position similar to that of elevation at 900. An incision was made in the skin on the trapezius muscle, palpated about 2cm from the axilla. Another 2 incisions were made more cephalic, one medial and one lateral in the arm next to the axilla forming a triangle. Through these 3 portals, tweezers were introduced for dissection and access to the muscle fascia. A cavity is created, since there are no natural cavities in this space. A trocar is introduced into each of the incisions, into the cavity formed. In the first portal on the trapezius muscle was introduced the camera of the robot Da Vinci SI, 8mm with optics of 00, and in the lateral and medial portals were placed the robotic working instruments.
Carbon dioxide was inflated at a constant 8mm Hg pressure through the chamber portal into the working cavity, stretching the soft tissues and opening the cavity. The work arms used the Maryland and De Bakey type dissecting tweezers and scissors, dissecting the lateral border of the latissimus dorsi muscle until its insertion, triangular interval, radial nerve, quadrangular space, and axillary nerve.
Conclusion: In this study the visualization of the desired structures was possible, without neurovascular lesions, suggesting that the use of robotic endoscopy may be a viable option for visualization of the quadrangular space and axillary nerve, as well as the radial nerve and the latissimus dorsi tendon.

Introduction

Robotic surgery has been earning space and expanding its possibilities of use in the last years, it has been used for a long time [1, 2, 3], and is already present as routine in daily medical practice in several surgical specialties to treat many pathologies [4,5]. Within orthopedics, we highlight the use of robotics in microsurgery [6,7] and surgery of the shoulder and elbow [8, 9, 10].
The possibility of associating the robotic technology with endoscopy further increases the challenge and the possibility of less invasive treatment, allowing a faster recovery for the patient, consequently shorter time of hospitalization and less absence in work [11].
Advantages of this method include movement accuracy, high resolution imaging with three-dimensional vision, gas infusion rather than saline solution (better visualization), filtering of the surgeon’s tremor when manipulating objects, movement scaling and hand-free camera manipulation [12, 13, 14, 15]. In addition, there is the possibility of remote surgery (telesurgery) where the surgical team can treat a patient far away1, 2 or a surgical team may be composed of professionals located in different cities or countries, treating the same patient simultaneously.
Some shoulder pathologies that need to be surgically treated by the posterior side of the shoulder may need aggressive and traumatic exposure with extensive manipulation of soft tissues. The possibility to use a minimal invasive approach can potentially be important for both the time of rehabilitation and avoiding local soft tissue adhesions. In Addition, when performing a large posterior open approach, one needs the use of tensioned retractors in order to keep the surgeon’s field in a suitable manner. The use of these tensioned retractors can eventually damage the deeper muscle layer as well as other neurovascular structures [16, 17, 18, 19, 20].
The minimally invasive procedures have demonstrated decrease of adhesions, avoiding reoperations and physical therapies during long times. Indeed, this advantage mentioned above make these procedures cost-effectives [11].
Some examples of minimally invasive shoulder surgery, are the arthroscopy and endoscopy of the extra-articular anterior region of the shoulder are already been used for manipulation of the coracoid process for the arthroscopic Bristow-Latarjet procedure [21,22] and manipulation of the long head of the biceps tendon after its exit from the rotator interval, as for biceps tenodesis.
This study is following a tendency for less invasive approaches, once there are not many minimally invasive procedures publications for most of the posterior structures and pathologies of the shoulder.
In shoulder surgery, the use of robotic-assisted surgery for better identification of the quadrangular space of the shoulder, identification of the axillary and radial nerves, and better identification of the latissimus dorsi muscle has not yet been proposed. This would make it possible to perform procedures such as the release of compressive syndromes of the axillary and radial nerves and for make possible, muscular transfers, focusing the latissimus dorsi muscle.
The objective of this study is to evaluate the feasibility of this method for the practical and daily use in the posterior space of the shoulder, verifying which structures can be better visualized and manipulated.
This study aims to provide data that will allow the treatment of many pathologies such as Quadrangular space syndrome, radial nerve compressive neuropathies, and manipulation of the Latissimus Dorsi tendon by using this new technology.

Material and Methods

Two fresh cadaver shoulders were used for the study, and in both anatomical pieces, the same procedure was followed: the shoulder was positioned as if in a ventral decubitus, the arm being maintained in a position similar to 900 elevation.
An incision was made in the skin, about 1 centimeter, in the lateral border of the trapezius muscle, palpated about 2-3cm from the axilla. Two other incisions were made more cephalic, one medial and one lateral in the arm near the axilla forming a triangle (Fig. 1). Through these 3 portals, tweezers were introduced to access the muscular fascia where a cavity was formed through blunt dissection. This space was made for triangulation as an initial working cavity, once there are no natural cavities in this space.

A trocar and a canula were introduced into each of the incisions, in a common direction in the cavity formed. In the first portal on the trapezius, the camera of the Da Vinci SI robot (Intuitive Surgical, Sunnyvale, CA, USA), with an optic of 00, is introduced.
Carbon dioxide was inflated at a constant 8mm Hg pressure through the chamber portal into the working cavity, stretching the soft tissues and opening the cavity. The work arms used Maryland Bipolar Forceps 8mm (Intuitive Surgical, Sunnyvale, CA, USA), DeBakey Forceps 8mm (Intuitive Surgical, Sunnyvale, CA, USA) and Hot ShearsTM Monopolar Curved Scissor 8mm (Intuitive Surgical, Sunnyvale, CA, USA).
The first objective was to clean the area around the camera so that we could initiate the best dissection and identification of the initial working cavity. After this first stage, we began the search for the superior border of the latissimus dorsi muscle. Once it was found we dissected its superior border laterally, until its entrance deep into the medial border of the long head of the triceps and looking to the lateral border of the lateral head of the triceps, it is possible to visualize the triangular interval, between the teres major muscle/Latissimus Dorsi(cephalic), the long head of the triceps (medially) and lateral head of the triceps originating in the humerus (laterally). In this muscular interval it was possible to visualize the radial nerve (Fig. 2).

Continuing the dissection laterally in direction to the axilla, and deep into the deltoid muscle, and in the cephalic direction and superficially to the tendon of the teres major muscle, to its upper border, the quadrangular space was visualized, between the teres major muscle (caudal), teres minor (cephalic), long head of the triceps muscle (medially) and the humerus (laterally). In this space the axillary nerve could be visualized and identified in its path from anterior to posterior (Fig. 3).

Returning to the upper border of the latissimus dorsi muscle, a point taken as the initial reference for the identification of the triangular interval, it was possible to follow its superior border laterally, and deeply to the long head of the triceps, until the insertion in the medial and antero-medial region in the diaphysis of the Humerus (at this time associating the internal rotation movement of the humerus, to make easily the visualization of its insertional region in the humerus.
All structures visualized and described above: limits of quadrangular space and triangular interval, axillary nerve, radial nerve were identified. After the robotic procedures an open approach was performed to confirm that there was no lesion of any structure (as tendons, vessels or nerves).

Results

As a result of this study, a successful visualization and manipulation of all target structures was obtained.
The study showed that it is possible to perform the procedures minimally invasively in the posterior region of the shoulder, with the help of the DaVinci robot (Intuitive Surgical, Sunnyvale, CA, USA)
There were no muscular or neurovascular lesions identified in this study.

Discussion

The visualization of the desired structures was achieved, and after dissection and detailed identification of the structures it was confirmed that all structures described did not present visually identifiable lesions, which adds reproducibility to the method, although the postoperative functional evaluation is not possible in an anatomical model.
There are few similar studies in the area of ​​orthopedics, especially in shoulder and elbow surgery using the aid of robotics, a practice already more widespread in other surgical areas, but which have been gaining space and recent publications23, 24, 25.
The described neurovascular structures were identified in this study, in the similarly as that they were comparatively identified in other studies in the literature10, 23, 24, 25.
The visualization and partial manipulation of the latissimus dorsi muscle has already been reported, in order to aid the transportation of the muscular pedicle, with technique that was used as reference for our study25.
Axillary nerve identification has also been described6, 7, 10, making a contribution to our study and confirms the viability of the method.
The reproducibility of the method described here may aid in performing procedures for shoulder muscle transfers using robotic assistance.
Regarding bleeding, studies in live patients have shown that the air insufflation have been effective on avoiding bleeding9.
We hope to encourage further studies in the area, both in improve identification of anatomical structures and performance of procedures in anatomical models (cadavers), as well as the clinical applicability in the treatment of pathologies in the posterior region of the shoulder.

Conclusion

In this study the visualization of the desired structures was possible, without neurovascular lesions, suggesting that the use of robotic endoscopy may be a viable, safe and non-invasive option for visualization of the quadrangular space, axillary nerve, radial nerve and the dorsal muscle tendon.

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Dr. Jose Carlos Garcia Jr

Dr. Márcio Eduardo Kozonara

Acta of Shoulder and Elbow Surgery | Volume 2| Issue 1 | Jan-Jun 2017 | Page 28-31| Eric Wagner, John W Sperling

Authors: Eric Wagner [1], John W Sperling [1]

[1] Mayo Clinic Rochester-MN-USA

Address of Correspondence
Dr. Eric Wagner
Mayo Clinic Rochester-MN-USA
Emial: wagner.eric@mayo.edu

Abstract

Reverse shoulder arthroplasty has greatly improved the outcome of patients who required a shoulder arthroplasty but have concomitant rotator cuff pathology. The most important aspect of reverse shoulder arthroplasty is securing a stable glenoid baseplate. This may be challenging in cases with severe glenoid bone loss and also in revision cases. This purpose of this review is to cover the diagnosis, evaluation, and treatment of glenoid bone loss in primary and revision reverse shoulder arthroplasty
Keywords: Reverse shoulder arthroplasty, glenoid bone loss, outcomes.

Introduction

Since its introduction in France in the early 1990s and its approval by the Food and Drug Administration in 2003, the indications for the reverse prosthesis have expanded exponentially [49]. Reverse shoulder arthroplasty (RSA) has become a successful treatment option for patients with advanced glenohumeral arthritis and whose rotator cuff pathology precludes the use of anatomic style prostheses. Indications for the reverse arthroplasty include rotator cuff tear arthropathy, proximal humerus fractures and their sequelae, inflammatory arthritis, revision arthroplasty, and glenoid bone loss in the primary and revision settings [10; 20; 38; 39; 44].
In the setting of glenoid bone loss, the reverse prosthesis provides the surgeon with multiple options to achieve a functional, stable shoulder. However, all of these options are dependent on establishing a stable glenoid baseplate in the correct location and version. In the setting of advanced glenoid bone loss, this can be difficult to achieve. Furthermore, the semi-constrained nature of RSA places increased stresses on glenoid fixation, which may lead to glenoid component loosening and implant failure [5; 7; 8; 37; 40]. Although this is often encountered in the primary setting, severe glenoid bone loss can be particularly challenging in the revision setting.
This purpose of this review is to cover the diagnosis, evaluation, and treatment of glenoid bone loss in primary and revision reverse shoulder arthroplasty.

Glenoid Bone Loss: Etiologies, Evaluation, and Classifications

Etiologies of Glenoid Bone Loss
Understanding the etiology for glenoid bone loss is critical to effectively managing patients, as many of the causes present and progress with specific unique patterns. An in depth understanding enables the surgeon to both counsel patients about their nonoperative and operative options, the likelihood of disease progression, and their reconstructive options. Although proximal humerus fractures and their sequealae can be associated with glenoid bone loss, it is not as commonly seen as with the other indications for reverse shoulder arthroplasty.
In the setting of rotator cuff tear arthropathy, a superior glenoid bone loss pattern is often seen. Occurring in up to 40% of cases of rotator cuff tear arthropathy [10], advanced superior glenoid wear can often be difficult to recognize and plan for preoperatively. Failure to adequately address the superior erosion can lead to excessive superior tilt of the glenoid component, increasing the risk of scapular notching and subsequent glenoid component failure[13; 30].
In the setting of primary osteoarthritis (OA), posterior glenoid wear is often seen, leading to glenoid retroversion in severe cases. In Walch’s classic article, greater than 50% of patients with advanced shoulder OA had this abnormal glenoid pattern with some degree of subluxation45. In cases of severe posterior erosion and/or glenoid retroversion, failure to correct this bony defect can lead to poor outcomes related to poor function, instability, and glenoid loosening from malpositioned components with poor underlying bone stock [10; 22; 46].
In the setting of inflammatory arthritis and associated shoulder arthropathy, there is usually a central glenoid erosion pattern and subsequent medialization of the joint line. Reverse arthroplasty is often indicated in these patients, given their either torn or non-functional rotator cuffs as a result of the mechanical disadvantage from joint medialization, as well as their eventual proximal migration of the humerus over time [2]. In the setting of reverse arthroplasty, excessive medialization can lead to a biomechanical disadvantage, compromising shoulder function, stability and potentially increasing the incidence of scapular notching [4].
In the revision setting, glenoid bone loss can be of many different patterns, depending on the remaining bone stock after implant removal. When revising a hemiarthroplasty, the glenoid erosion patterns often mimic those seen in the primary setting, as previously described. During the revision of a total (anatomic or reverse) shoulder arthroplasty, prior baseplate loosening or removal of a well-fixed glenoid component has the potential to be associated with large glenoid bony defects. The bone loss pattern is variable, and when it is severe enough, can markedly compromise baseplate fixation and overall component stability [43].

Evaluation of Glenoid
A comprehensive preoperative evaluation is imperative prior to performing any type of arthroplasty in the setting of glenoid bone loss. Preoperative radiographic evaluation should include anteroposterior (AP) Grashey in internal rotation and external rotation, axillary, and scapular Y views. The axillary view is especially useful to assess for central, anterior, and posterior glenoid bone loss that might predispose to excessive anteversion, or retroversion. The AP view estimates the central defects that could lead to excessive medialization, or superior defects that might lead to implantation of the glenoid component with a superior tilt.
In addition to standard x-rays, a two-dimensional computed tomography (CT) scan (with slice thickness <1.5 mm) is critical to understand the glenoid bone loss pattern and morphology. The location and extent of the defect is determined using the standard centerline perpendicular to the glenoid surface, exiting on the anterior aspect of the scapular neck [3; 27]. The amount of bone available for central screw or post placement and location of the defect will allow the surgeon to plan their preferred method to reconstruct the glenoid preoperatively. It is also important to determine the effects of the arthritis on the native glenoid version, as studies have found increases in retroversion from 6-10o from arthritis alone [19]. Digital templating software may also be used to estimate not only the size of the new glenoid components, but also the need and size of augments or bone graft, in the primary setting [15; 42]. However, in revision surgery it is common for the surgeon to have to modify their strategy according to intraoperative assessment of glenoid bone loss after component removal.

Glenoid Bone Loss Classifications
There are multiple classification systems that have been established to describe the classic glenoid morphology patterns in the setting of glenoid bone loss.
The Walch classification describes the patterns of posterior glenoid bone loss, as seen in OA: A1 minor central glenoid erosion, A2 marked central glenoid erosion, B1 minor posterior glenoid erosion, B2 marked posterior glenoid erosion with retroversion (often above 10o), C glenoid retroversion >25o45. This is useful in the setting of larger glenoid defects, to help the surgeon compensate for retroversion and the potential need for baseplate augmentation posteriorly.
The Favard Classification describes the patterns of superior glenoid bone loss, as often seen in rotator cuff arthropathy: E0 superior humeral head migration without glenoid erosion, E1 concentric erosion of the glenoid, E2 superior erosion of the glenoid, E3 superior erosion of the glenoid extended inferiorly30. This is particularly useful when planning to compensate for superior wear and the need to avoid superior tilt of the baseplate.
The Levigne classification describes the patterns of central glenoid bone loss, as seen in rheumatoid arthritis: Stage 1 minor central erosion, Stage 2 central erosion to the level of the coracoid, Stage 3 central erosion medial to the level of the coracoid. This is useful in cases of marked medialization, when the surgeon desires to restore close to normal glenoid lateral offset, potentially improving shoulder function, stability, and incidence of scapular notching [4].
In the revision setting, the algorithm proposed by Wagner et al. helps to determine the need for and type of bone graft, or alternatively, component augmentation, with the goal of obtaining at least 30-50% implant-bone contact to facilitate adequate ingrowth [43]. Furthermore, as in primary arthroplasty, the graft, eccentric reaming, or component augmentations can be used to correct superior tilt, retroversion, or excessive medialization.

Glenoid Bone Loss: Primary Reverse Arthroplasty
Treatment Strategies
The strategies for addressing glenoid bone loss during reverse shoulder arthroplasty all have a goal of restoring glenoid version, offset, and tilt. Three of the strategies discussed in this article, which all have had moderate success in small short-term studies, include eccentric reaming, use of a lateralized implant, bone grafting, augmented components[14; 10; 23; 27; 33; 38; 43; 50].

Eccentric Reaming +/- Lateralized Implant
Although the algorithm was designed for the setting, its notion of attempting to obtain 50% contact between the baseplate and the glenoid is applicable to the primary setting (Figure 2). In cases of mild glenoid bone loss, eccentric reaming can be a very effective strategy to maximize the contact area of the implant-bone interface and potentially improve ingrowth [27]. A critical step when performing this technique is to determine the correct glenoid version and tilt, as estimated on preoperative imaging [19]. The center guide pin should be placed in the axis of the scapular spine, along the inferior part of the glenoid. Although it is important to maximize implant-bone contact, excessive reaming should be avoided due to the concern of removing unnecessary glenoid bone stock and over medializing the implant. In particular, there is concern with this technique regarding excessive violation of the subchondral plate thought to be important for glenoid component stability [14; 46]. This would cause the implant to be reliant on weaker cancellous bone, potentially compromising stability and ingrowth. Therefore, morselized corticocancellous allograft or autograft can be packed into any remaining small defects after the eccentric reaming has been finished [17; 43]. Another technique utilizes a lateralized prosthesis to overcome any medialization from the glenoid erosion and eccentric reaming [9].
There have been very few studies that have specifically examined the use of eccentric reaming alone or in combination with glenoid bone grafting. Correcting the underlying glenoid deficiency is critical to correct glenoid tilt and version. Furthermore, preoperative subluxation has been associated with poor outcomes after shoulder arthroplasty [22]. Klein et al. examined 56 reverse shoulder arthroplasties with glenoid bone defects treated with eccentric reaming, with 22 requiring augmentation with bulk autograft [27]. At 31 months follow up, patients had a significant improvement in pain scores and shoulder function, including ASES scores and shoulder motion. Those shoulders that required bone grafting did not have different outcomes compared to those that did not require grafting. Only 2 (4%) required revision surgery secondary to infection. In regards to preoperative subluxation, their review of 240 patients that underwent reverse shoulder arthroplasty, Wall et al. examined 33 patients who required a reverse prosthesis for osteoarthritis associated with static posterior humeral head subluxation [47]. These patients did well, with postoperative Constant score of 65, elevation of 1150, and low number of complications.

Glenoid Bone Grafting
In cases of moderate to severe glenoid bone loss where achieving 50% or greater contact area between the baseplate and native bone is not possible, glenoid bone grafting can help to make up for this bone loss (Figure 2). As detailed above, minor central or peripheral cases of glenoid bone loss can be managed utilized morcellized corticocancellous bone graft. However, in cases of larger defects, structural grafts are needed to achieve glenoid component stability, while restoring near anatomic version, tilt, and offset. The source of the structural graft in the primary setting is often from the resected humeral head [4; 28; 29; 32]. Alternatively, if there is insufficient bone in the humeral head due to prior pathology, trauma, or surgery, the autologous tricortical iliac crest or allogenic structural graft can be utilized1; [25; 33].
It is critical for the surgeon to preoperatively plan the desired reconstruction in these cases of severe glenoid bone loss. In cases of superior glenoid bone loss, it is critical to avoid superior tilt and achieve at least neutral, or even slight inferior glenoid tilt with the use of a structural graft [29]. Peripheral defects require structural grafts compensate for excessive glenoid anteversion (anterior) or retroversion (posterior) [43]. Central defects require bone graft to restore glenoid offset through lateralizing the prosthesis4. Furthermore, in cases of marked medial wear, it is important to have at least 8-15 mm of bone available for the central peg and peripheral screw purchase [4; 31; 35]. In fact, a finite element analysis by Hopkins et al. suggested 16-30 mm of screw purchase in bone lead to a 30% reduction in micromotion18. In all of these cases, the structural bone graft is contoured prior to implantation, then either secured with the baseplate and screws alone, or in combination with separate screws outside the baseplate. Although the indications for glenoid bone grafting with the reverse arthroplasty are still evolving, cadaveric studies involving the anatomic arthroplasties suggest cases of 15o or more of glenoid retroversion should be corrected with structural bone graft [6; 11].
In anatomic total shoulder arthroplasty, glenoid bone grafting is associated with increased rates of complications, as glenoid deficiency leads to increased rates of glenoid retroversion, failure of graft incorporation, and glenoid component loosening leading to resultant revision surgery [16; 24; 33; 34; 41]. To date, there remain few studies examining the results of glenoid bone grafting using the reverse prosthesis. Although not in the setting of glenoid bone loss, Boileau et al. examined 42 patients who underwent structural humeral head grafting to increase the lateralization of glenoid components in in patients without marked bone loss4. At a minimum of 2 years follow-up, no graft resorption or glenoid loosening occurred, 41 of 42 had full incorporation of the graft, and only 19% rate of scapular notching.

Augmented Component
The role of augmented glenoid components is controversial, as its specific indications continue to evolve. Its use has been described in anatomic [12; 21; 26; 34; 36; 48] and reverse [23; 50] shoulder arthroplasty, mostly in the setting of a marked peripheral bone defect (E.g. Walch B2) or with severe glenoid destruction requiring a custom made, patient specific implant. In anatomic shoulder arthroplasty, Rice et al. examined 14 posteriorly augmented keeled polyethylene glenoid components [34]. At a mean 5 year follow-up, patients achieved predictable pain relief and restoration of shoulder function, but had a relatively high rate of unsatisfactory results from recurrent instability and posterior subluxation. Two other small series by Gunther et al.[12] and Sandow et al.[36] reported on custom made augmented glenoid components, demonstrating better short-term results in series of 7 and 10 patients, respectively.
There remains a paucity of long-term studies examining the use of augmented glenoid components, particularly with reverse shoulder arthroplasty. Undoubtedly, there is tremendous potential in cases of severe medial or peripheral bone loss, however, further investigation is required to better elicit its role in reverse shoulder arthroplasty.

Glenoid Bone Loss: Revision Reverse Arthroplasty
Considerations
Although there remains a need for further study regarding glenoid bone loss and the reverse prosthesis in the primary setting, there is even less information regarding its use in the revision setting of glenoid bone loss. Neyton et al. reported on the early outcomes of 9 patients who underwent revision reverse shoulder arthroplasty with glenoid bone grafting33. At 31 months follow-up, patients had a relatively low Constant Score, but had significant pain relief without signs of glenoid loosening, graft failure, or need for revision surgery. Kelly et al. examined 28 patients who underwent revision shoulder arthroplasty using the reverse prosthesis, with 12 shoulders treated with glenoid bone grafting [25]. Although their series reported a complication rate of 50% and a 23% revision rate at 34 months follow up, there was a high level of satisfaction in this complex patient population with 29 of 30 shoulders with a stable prosthesis at last follow up.
We reported on our outcomes of 41 patients who underwent glenoid bone grafting in the revision setting utilizing a reverse prosthesis [43]. At a mean 3 years of follow-up (range, 2-5), 7 (18%) required revision surgery with the majority (n=4) for glenoid loosening. Furthermore, 6 patients had signs of moderate or severe glenoid loosening at last radiographic follow-up, with factors such as increasing BMI, smoking, and a lateralized implant center of rotation increasing the risk. However, patients that did not undergo revision surgery had predictable pain relief, improvements in their shoulder motion, and high satisfaction. It should also be noted that only 5 patients were treated with structural grafts, potentially leading to the higher rates of glenoid loosening.

Bone Grafting Treatment Algorithm in Revision Reverse Arthroplasty
From our past experience, we have a proposed treatment algorithm (Figure 1) [43]. In patients that the glenoid is felt to be inadequate for stable fixation in an acceptable position, glenoid bone grafting is strongly considered. Implant-bone contact should be maximized, as well as preserving stability and shoulder motion. In cases with a small glenoid defect, a smaller baseplate can be utilized to maximize contact with the glenoid surface, while filling in the remaining defect with corticocancellous graft. However, in larger bone defects, a larger baseplate is utilized in combination with a structural graft.
As mentioned previously, structural autograft or allograft can be utilized for a variety of glenoid bone defect locations. Larger peripheral defects should be augmented by structural grafts to restore version and improve implant-bone contact. Superior defects predispose to superior tilt, and therefore, morselized (for smaller defects) or structural (for larger defects) can be used to restore neutral or inferior tilt and reduce the risk of scapular notching. And finally, large central (or global) deficiencies predispose to medialization, and thus require structural grafts to restore the natural lateral offset. We recommend if 80% of the undersurface of the glenoid baseplate is not in contact with the baseplate, morselized bone grafting is considered, while structural graft is considered in cases where less than 30%-50% of the component is in contact with the glenoid to augment the glenoid contact and fixation.

References

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Dr. Eric Wagner

Dr. John W. Sperling