Chapter 4: Clinical procedure

Theatre organization 

Arthroscopic surgery of the shoulder is a highly technical and demanding form of surgery. It requires special instrumentation and a highly skilled team consisting of surgeon, anaesthet­ist, scrub nurse and circulating nurse. Diagnos­tic arthroscopy of the shoulder, on the other hand, requires little more than an arthroscope, light source and hook probe, as well as a large helping of enthusiasm and determination on the part of the surgeon, and tolerance from the anaesthetist and the nursing team. Initially even diagnostic arthroscopy takes time, and the goodwill of the operating team is increased if they can all follow events on a television monitor.#

Since shoulder arthroscopy is a very special­ized form of surgery, it is best performed in a dedicated day-case arthroscopy suite. Failing this, a good-sized general or orthopaedic theatre, with nurses trained in arthroscopic techniques of the knee, is the next best situation. To perform this type of surgery in a general surgical theatre with untrained staff needs an extremely optimistic outlook from the surgeon!

The surgeon should have a good training in arthroscopic surgery of the knee before under­taking arthroscopy of the shoulder, and this must be combined with an extensive know ledge of shoulder anatomy, pathology, and an ability to undertake open surgery of the shoul­der in an experienced and competent fashion. The surgeon should then attend a shoulder arthroscopy course, and practise on shoulder models before attempting any form of arthro­scopic procedure on the shoulder of a patient. The surgeon may wish to practise on cadaver shoulders but, unless very fresh cadavers are used, the shoulder soon shrinks and becomes difficult to move, and the whole process becomes rather sordid. It is far better to practise on models and to gain experience by assisting a surgeon who is competent in this technique.

A good theatre layout is shown in Figure 4.1 and is based on the dedicated suite of Dr L Johnson's unit, at Ingham Medical Center, Lansing, Michigan. The patient lies in the lateral decubitus position with the surgeon directly behind his/her shoulder. A Mayo stand with the principal arthroscopic equipment required for the procedure is placed directly opposite the surgeon, and the scrub nurse stands alongside the Mayo stand ready to hand instruments to the surgeon when needed. Directly beyond the instruments is the television stand on which are placed the television monitor, camera equip­ment, light source, shaver system and video recorder. The arm of the patient is supported by a shoulder holder. An extra Mayo stand with accessory instruments is placed to the right of the surgeon and the first assistant stands to the surgeon's left.

Figure 4.1 Suggested theatre setup for shoulder arthroscopy. An, Anaesthetist; N, Nurse; S, Surgeon; A, Assistant; M and M2, Mayo stands; TV, Television monitor; CSV, Camera, Shaver, Video.

Equipment

For diagnostic shoulder arthroscopy

A standard 30 degree knee arthroscope is used for shoulder arthroscopy. The shoulder is a large joint and we have found that a small diameter arthroscope gives too small a picture of the joint, as well as having difficulty deliver­ing enough light to illuminate the far recesses of the joint cavity. Obviously a good light source and either sterile saline or Hartmann's solution is required along with the arthroscope. The only other piece of equipment needed is a wide-bore needle to establish an outflow, and a hook probe.

For arthroscopic surgery of the shoulder

Basics

For simple surgery, such as the removal of loose bodies and synovial biopsies, the only equipment needed are the standard arthrosco­pic tools of the trade as used for knee surgery, in particular a pair of arthroscopic grasping forceps, basket forceps and small pituitary rongeurs (Figure 4.2).

Figure 4.2 Basic instruments: from left, scissors, graspers, basket forceps, and hook probe.

Television system

For any form of more complex surgery, a television system is mandatory. Again any system that works for the knee will work for the shoulder. There have been rapid advances in camera technology recently and, in buying a camera system, the minimal requirements are a lightweight balanced camera head capable of repeated immersion for sterilization, with a white set memory to establish colour balance, allied to a high intensity light source and high resolution colour monitor

If the shoulder is being arthroscoped in the normal lateral position, then the television moni­tor should be placed opposite the surgeon, the centre of the screen being on a level with the surgeon's eye. One problem that arises in shoulder arthroscopy is that if the arthroscope is changed from the routine posterior portal to the anterior portal, the surgeon can feel awk­ward still looking forward at the monitor in front of him. Body image becomes distorted and triangulation difficult, similar to attempting to perform internal fixation of a femoral neck fracture under image intensifier control with the intensifier image upside down and back to front. The dedicated arthroscopist will have a second monitor stationed behind him and, when he changes to the anterior portal, he then looks over his shoulder at the second monitor, or moves to the other side of the operating table and looks at the second monitor, in order to overcome 'body image' problems.

Once a good television system has been purchased, it costs little more to link a video recorder into the system to get a permanent record of the procedures. For the surgeon who has everything, this system can be linked to printers and recorders which can store images on computer disk, or reproduce them as slides, prints, transparencies, or videotape record­ings. A character generator can also be used to identify each recording.

Whereas a large amount of arthroscopic surgery of the knee can be performed with hand-operated instruments, arthroscopic surgery of the shoulder really requires powered instrumentation. Powered systems mean that there is less need for instruments to be passed in and out of the joint, for, with most of these systems, the excised tissue is sucked out of the joint down the shaver or bur shaft. This is important, as the shoulder is surrounded by a greater mass of soft tissue than the knee, making entry more difficult and more traumatic to the tissues. The fewer times a portal is transgressed, the better for the shoulder.

Arthroscopic subacromial decompression can be performed with a powered soft tissue resector and powered burs alone (see Chapter 8). However, the amount of bleeding, and therefore the time taken to complete the proce­dure, is reduced if an electrosurgical apparatus is used to define the area of resection and cut the soft tissue off the undersurface of the acromion first (Figure 4.3).

Shoulder repair is dependent upon very specialized equipment, and the choice depends upon the surgeon's philosophy regarding method of repair (see Chapter 7). For staple repair, Instrument Makar staples are needed (Figure 4.4); for the Caspari-type repair, the Caspari punch is needed (Figure 4.5) and, for the Morgan suture technique, Bowen needles are required (Figure 4.6). Many new techniques are being developed and there is no doubt that these will require specialized instruments of their own.

Figure 4.3 Electrosurgical apparatus is useful for subacromial decompression.

Figure 4.4 The Instrument Makar arthroscopic staple.

Figure 4.5 The Caspari suture punch for suture repair

Figure 4.6 Bowen needles for suture repair.

Arthroscopic photography

Good documentation of shoulder arthroscopy still requires 35 mm photography, although computer technology may soon make this redundant and allow high quality hard copy to be made from videotapes. It is really essential to have a power winder, or two hands will have to be used on the camera body and contamina­tion of the arthroscope may occur as the surgeon's natural reaction is to steady the arthroscope itself for the next shot. High-speed film is needed, such as 1000 or 640 ASA tungsten film.

Shoulder holders

A shoulder holder is a suspension device for the arm, used to distract the glenohumeral joint. They vary from the homemade bent piece of tubing (Figure 4.7) to extremely sophisticated devices such as the electrically switched and vacuum-powered arthrobot (Figure 4.8).

Great concern has been expressed about the relationship between postoperative nerve palsies and the use and duration of pull from shoulder holders during shoulder arthroscopy. Paulos et al1 reported a 30 per cent incidence of transient paraesthesias following shoulder arthroscopy and Andrews, Carson and Ortega[2] implicated traction as a cause of ulnar and musculocutaneous neuropraxias during shoul­der arthroscopies.

Klein, France and Mutschler[3] performed a series of experiments to measure the strain on the brachial plexus exerted by a shoulder holder. They mounted strain gauges to the upper trunk, lateral cord, median nerve and radial nerve of five fresh cadavers, which were then put in the lateral decubitus position for shoulder arthroscopy and the strain on the plexus measured in relation to arm position and load. They concluded that the best position of the arm in terms of maximum visibility associ­ated with minimum strain on the plexus was either 45 degrees of forward flexion and 90 degrees of abduction, or 45 degrees of forward flexion and 0 degrees of abduction.

Figure 4.7 A very crude shoulder holder can be made from a bent pipe or a drip stand.

Figure 4.8 The arthrobot is a highly sophisticated shoulder holder.

Andrews et al[2] suggest that the best position for the arm is at 60-70 degrees of abduction and 15 degrees of forward flexion with 4 5-9 kg weight  applied   to  the   traction   apparatus. Caspari4 also feels that a traction apparatus is essential  because traction  supplied  by an assistant is inconsistent and wanes as the assistant tires. Matthews[5] suggests that the arm should be placed in 45-60 degrees of abduction and 15 degrees of flexion, but that no more than 4.5 kg weight should be used. Matthews[6] has  also  shown  how  abduction should be released before proceeding to sub­acromial endoscopy as, with the arm at the side, the volume of the subacromial space is doubled from the volume with the arm at 45 degrees of abduction. For arthroscopic repair of the shoulder, Matthews uses not one but two shoulder   holders  (Figure  4.9),   the  second distracting the glenohumeral joint and being attached to the arm at the mid-humeral level. It is essential, if using a two-holder technique, to pad the humerus copiously in order to prevent neuropraxia to the median and ulnar nerves.

Figure 4.9 Two shoulder holders can be used to reduce pressure on the brachial plexus and distract the glenohumeral joint more thoroughly.

Gross and Fitzgibbons[7] also recommend applying the traction perpendicular to the humerus rather than along the line of the arm. They suggest that this elevates the humerus from the glenoid rather than distracting it into a subluxed position. This accentuates labral pathology and allows for better visualization of the lower third of the glenoid rim, while causing very little strain on the brachial plexus. They suggest that this should eliminate traction neuropraxias.

Preoperative procedures

Anaesthesia

Local anaesthesia may be used for shoulder arthroscopy and Warren et al[8] have reported a series of 44 arthroscopic subacromial decom­pressions performed under scalene block with­out anaesthetic problems. However, general anaesthesia for shoulder arthroscopy is prefer­able. General anaesthesia prevents embar­rassment to the surgeon and loss of faith by the patient during the learning curve of the proce­dure, when the surgeon's dexterity may not match the patient's expectations! It is essential that the patient is intubated in order to remove both the anaesthetist and the anaesthetic equipment from the operative field, and to allow the surgeon to reach across the patient's head. The patient should be adequately monitored and all pressure areas should be properly padded.

When the lateral decubitus position is used, an axillary roll should be placed under the patient in order to prevent undue strain being placed on the brachial plexus of the unoper-ated side (Figure 4.10).

Figure 4.10 An axillary roll is placed under the patient to protect the brachial plexus of the unoperated side.

Draping the patient

The whole of the shoulder, arm and hand of the side to be arthroscoped is prepared with chlorhexidine in spirit, paying particular atten­tion to the axilla. The preparation must extend to the midline of the chest to back and front, and include the neck (see Figure 4.11). A glove is placed over the hand, after preparation, and the arm is held by the assistant. A stockinette is then rolled down the arm (Figure 4.12).

Figure 4.11 Preparation of the skin must be adequate, extending to the midline and up onto the neck.

Figure 4.12 After the hand has been prepared, a stockinette is rolled down the arm.

Figure 4.13 Drapes are then placed over the patient's body, from the axilla down.

Figures 4.14 and 4.15 A sterile 'U-drape' is placed to prevent irrigation fluid leaking over the patient's hair and face during the procedure.

Figure 4.16 Draping is completed with an arm drape through which the arm is placed.

Figure 4.17 When starting to perform shoulder arthroscopies, it is useful to mark the landmarks of the acromion, the clavicle and the coracoid with a skin marking pen prior to portal placement.

The draping starts with waterproof drapes being placed to cover the patient's body, from the axilla downwards (Figure 4.13). A water­proof 'U-drape' is then placed over the patient's head to prevent irrigation fluid and blood from reaching the unprepared parts of the patient (Figures 4.14 and 4.15). A further drape with a hole in the centre is then placed over the arm (Figure 4.16). The skin markings of the clavicle and acromion are marked with a sterile skin marker, as well as the coracoid process and the posterior portal entry site, one thumb's breadth below and medial to the posterior angle of the acromion, as shown before drap­ing in Figure 4.17.

Positioning

The usual position for shoulder arthroscopy is the lateral decubitus position. A pillow is placed between the legs to prevent undue pressure and the trunk is supported with well-padded surgical posts (see Figure 4.10). If diagnostic arthroscopy alone is being undertaken, there is no need for a shoulder holder to be used, as the surgical assistant can provide distraction when needed. However, if arthroscopic surgery of the shoulder is being undertaken, then the arm should be connected to the shoulder holder using a proprietary traction apparatus.

Skyhar et al[9] have described the use of a 'beach-chair' or sitting position for shoulder arthroscopy. They have used this position for over 50 consecutive patients for arthroscopic debridement, arthroscopic subacromial decompressions and arthroscopic shoulder stabilizations. Matthews[6] also suggests that a 'beach-chair' position be used for subacromial decompression as this increases the subacro­mial space and allows easier access if the shoulder or subacromial space requires open surgery. Gross and Fitzgibbons[7] suggest that the lateral decubitus position should be mod­ified to a semilateral position by letting the patient rotate 30-40 degrees posteriorly. This places the glenoid parallel to the floor, which allows more comfortable arthroscopy and instrumentation.

Even with the use of television apparatus, arthroscopic techniques are not always as aseptic as open orthopaedic procedures. Therefore, if there is a need to proceed to open surgery, it is better to treat the open procedure as an entirely new operation. The patient should be repositioned, reprepared and draped, all instruments should be changed and the surgeon will need to rescrub and gown.

Introducing the needle

A needle is then introduced from the posterior portal entry site, aimed at the surgeon's finger, which has been placed on the coracoid pro­cess (Figure 4.18). At this point, it is of benefit to ask for silence in the operating theatre. The assistant then distracts the arm towards the patient's feet, and resistance is felt as the posterior capsule is encountered, followed by a sucking sound as the joint is entered. If there is an effusion within the joint fluid may then escape from the needle showing correct place­ment (Figure 4.19), but this is rare.

Figure 4.18 A needle is inserted from the posterior portal aimed at the coracoid process.

Figure 4.19 A sucking noise is heard as the needle enters the joint. If there is an effusion (which is rare) joint fluid may exit from the needle.

A 50 ml syringe is connected to the needle and the joint is prefilled with irrigating fluid (Figure 4.20). We have found that the shoulder will take over 40 ml on average, and up to 70 ml in dislocating shoulders. Free backflow of fluid into the syringe shows correct placement of the needle inside the glenohumeral joint. If there is no   backflow,   then   the   needle   should   be removed and replaced in a better position.

Difficulty can be encountered in prefilling the joint for one of several reasons. The first is inexperience which, of course, is unavoidable. The second is through obliteration of the landmarks by obesity or muscle. A longer needle (spinal needle) is needed. The third reason may be rotator cuff tears, which allow the fluid to pass straight out of the joint into the subacromial space. The last reason is in the stiff painful joint, where the joint is obliterated by synovitis.

Figure 4.20 The joint is prefilled with sterile irrigation solution. Free backflow shows correct placement.

Figure 4.21 An incision along the Langer's line is made at the portal site.

The needle and syringe are removed follow­ing prefilling. The skin is then punctured using a No 11 surgical blade at the portal site. The incision should follow Langer's lines, and should be long enough to allow the insertion of the arthroscope (Figure 4.21). The sharp trochar and cannula are inserted, following the needle track and aiming for the finger on the coracoid process (Figure 4.22). Fluid is seen to escape from the open side tap showing correct placement (Figure 4.23). The arthroscope is inserted in the place of the trochar, and connected to the irrigation fluid and to the light source (Figure 4.24). The arthroscopic camera is then connected (Figure 4.25), and the camera and light source switched on.

Figure 4.22 The sharp trochar and cannula are then placed following the line of the withdrawn needle.

Figure 4.23 Fluid escape from the prefilled joint shows successful placement.

A needle is placed via the anterior portal, the surface marking of which is halfway between the coracoid process and the anterior edge of the acromion, pointing directly towards the arthroscope (Figure 4.26). Entry is confirmed by the outflow of irrigation solution (Figure 4.27). This ensures a free movement of fluid which keeps the joint clear of blood. The difference in calibre of the entry and exit cannulae ensures that pressure is maintained within the joint, as well as establishing a flow.

Figure 4.24 The arthroscope is inserted in the cannula, and irrigating fluid and light cable attached.

Figure 4.25 The arthroscope camera is finally attached.

After the joint has been examined visually (see Chapter 5), extra information is gleaned by palpation. A hook probe needs to be passed from the anterior portal (Figure 4.28). Instru­ments can be placed into the joint through the anterior portal freehand or through a cannula.

Figure 4.26 A needle is then placed from the anterior portal pointing towards the arthroscope

Figure 4.27 Escape of irrigation fluid shows successful placement of the needle, which ensures free flow of fluid and keeps the joint clear of blood.

Cannulation

If the instruments are passed freehand, it is best to make a track for them first, by inserting a sharp trochar and cannula down the anterior portal. However, this does not necessarily guarantee that the instruments will follow the track and, if repeated passages are envisaged, then it is best to insert a cannula. There are two methods to pass a cannula, the outside-in technique or the inside-out technique.

Figure 4.28 A hook probe is then inserted through the anterior portal, using either the inside-out or outside-in technique.

Figure 4.29 The superior portal can be used for irrigation.

Outside-in technique

The arthroscope is brought into the foramen of Weitbrecht and  rests on the synovium just above the subscapularis tendon. In the thin patient, the arthroscope can be felt tenting up the soft tissues. Alternatively, the room lights can be lowered, which makes light from the arthroscope visible through the skin, if thin enough. Having marked this site as the insertion site, a 5mm skin incision is made and the arthroscope backed off so that the plunging sharp cannula does not damage it. The trochar and canula are inserted, aiming at the site from which the arthroscope tip has been withdrawn. The sharp trocar and cannula are carefully advanced with rotaion until joint entry occurs.

Inside-out technique

The inside-out technique is more elegant and was devised by Dr A. Wissinger. The arthro­scope is advanced through the foramen of Weitbrecht above the subscapularis tendon, as before, until it rests on the synovium. In this position, the arthroscope is removed, leaving the arthroscope cannula resting on the syno­vium at the front of the shoulder. A long sharp rod (Wissinger rod) is now passed down the arthroscope cannula from the back of the shoulder and pushed out of the front of the shoulder. As it tents the skin, a 7 mm stab incision is made over it. A cannula is then placed over the rod in front of the shoulder and 'railroaded' down the rod and into the shoulder joint. With both cannulae inside the shoulder joint, one from the posterior portal and the other from the anterior portal, the Wissinger rod is withdrawn and the arthroscope reinserted.

An additional portal can now be used for irrigation (Figure 4.29), the superior or Neviaser portal (see Chapter 3). A Verres needle is placed medial to the acromion in the suprasca­pular fossa and triangulated to enter the super­ior part of the joint (Figure 4.30). Some concern has been expressed10 that this portal may damage the rotator cuff but, in dissections at Nottingham and at other centres, it has been seen  that  the  needle  passes  through  the muscle of supraspinatus and not the tendon (Figure 4.31). The needle can be tucked down in  the  posterior gutter to  avoid instrument clashes. Most procedures can be performed with a two-portal technique, and this third portal is rarely needed.

Figure 4.30 The Verres needle can be used to suck blood from the joint.

Figure 4.31 The needle passes through muscle and not through tendon.

Bursal endoscopy

After the glenohumeral endoscopy has been performed, it is essential to pass on to the bursal side examination. The arthroscope can­nula and sharp trochar are passed either through the same posterior skin incision, or through a separate and slightly higher (cephalad) stab. The sharp trochar is exchanged for the blunt trochar and pushed forward under the acromion until the end of the trochar rests on the coracoacromial ligament. This is helped by the assistant pulling the arm downwards (caudad) with the arm to the side.

The most common error in bursal endoscopy is to fail to enter the bursa, and the reason for this is simply that most surgeons believe that the subacromial bursa lies under the acromion. In fact it can consistently be entered under the coracoacromial ligament but its extension under the acromion is variable. Bayley (perso­nal communication, 1989) has classified the bursa into three types: where the bursa extends under the anterior one-third of the acromion; where its posterior limit is the anterior edge of the acromion; and where it extends under the anterior two-thirds of the acromion.

In order to enter the bursa every time, therefore, the trochar must be inserted until it is anterior to the acromion and the free lateral edge of the coracoacromial ligament can be flicked on the end of the trochar. The trochar is now withdrawn and the arthroscope inserted. If a large cavity is seen (Figure 4.32), then irrigation may be switched on to expand the bursa. If all that is seen is cobwebs (Figure 4.33), then the bursa has not yet been entered, usually because the cannula is not far enough forward. The irrigation should not be switched on, as this will make entry more difficult. The process is repeated with the cannula further forward.

Figure 4.32 If the bursa has successfully been entered, then a large cavity is seen.

Figure 4.33 If the bursa has not been entered, then the arthroscope is in the subacromial areolar tissue and a 'cobweb' appearance will be seen.

Orientation within the bursa is more difficult as there are no helpful landmarks like the long head of biceps. It is therefore helpful at this point to insert two needles, one at the antero­lateral edge of the acromion and one at the acromioclavicular joint.

Operative portals for subacromial decom­pression are described in Chapter 8.