Archive for category: Uncategorized

Cervical syndromes
Cervical Spondylosis – Cord Compression Syndromes

There are a number of myelopathic syndromes

1. Transverse Lesion Syndrome
– most common
– little upper extremity involvement
– posterior column, spinothalamic, corticospinal tracts are predominantly involved to lower extremities

2. Motor System Syndrome
– bears a strong resemblance to ALS
– corticospinal and anterior horn cell dysfunction
– patient may have no sensory complaints, but motor function may be severely affected

3. Central Cord
– upper extremity worse than lower
– hand function affected the most has a poor prognosis

4. Brown Sequard
– unilateral cord compression – ipsilateral motor, contralateral pain and temp loss
– good prognosis

– correlating canal size and degree of myelopathy is difficult; the most important good prognostic factor may be minimal involvement; other favorable factors include symptoms

Hawkins-Bankart1
Surgical Technique

Bankart Repair – Dr. Hawkins

Positioning: Supine, 45o beach chair with head in Mayo headrest. Tip the legs up 20o, then tip the back up 25o to get 45o. The arm should be resting on the armrest. Head in the middle.

Prepping and Draping:

Shave the area. 10×10 steri-drape across the neck. Mark off the acromion and AC joint. The incision is made transversely in line with the fibers, about 1 cm medial to the lateral border of the acromion, and is about 10-12 cm long.

Approach

Anterior deltopectoral. The skin incision is vertical. Identify the top of the axillary fold with the shoulder adducted. Draw the incision vertically up from there. Then abduct the arm and carry the incision down 2 cm along the axillary fold.

Blade through the skin, then cautery to get through the epidermis to the subcutaneous fat. Use the mets once through the fat to identify the cephalic vein. Then de-roof the vein, and bluntly dissect between the deltoid and pectoralis muscles using your fingers. Crossing the deltopectoral interval superiorly and deeply is the deltoid branch of the thoracoacromial artery. This may bleed, but he does not generally go after it prophylactically – rather, he tries to mobilize it superiorly and out of the way. This should bring you down onto the conjoint tendon and the coracoid process. Use your finger to get above the coracoid process and clear the fascia our from above this. Then insert the coracoid retractor and use your mets to identify the very lateral border of the conjoint muscle/tendon complex. There is a well defined fascia here, so you need to get through this with the mets. Don’t be fooled into dissecting along the lateral border of the tendon, because you will denervate all of the muscle laterally. Gently mobilize the conjoint complex medially to identify the subscap tendon.

He uses a variety of incisions through the subscap tendon. Make a vertical incision about 1.5 cm medial to the insertion and gently cauterize down, careful not to go too far down and nick the anterior circumflex humeral vessel which lies at the inferior border. He sometimes hockey-sticks the incision medially. The trick to the cautery dissection is to watch for the crossing fibers – these are subscap tendon. When they disappear, then you are deep enough and are getting into the capsule. A trick is to go inferiorly into the muscle fibers of the subscap tendon, bluntly dissecting through them to ge to the correct plane of the capsule, then extend superiorly where the tendon and capsule are a bit more adherent and harder to separate. Superiorly, things get a bit tricky in that you need to continue to leave an adequate cuff of tendinous insertion to suture back to. A cobb may be helpful in sweeping the subscap tendon off the capsule, and similarly, a 15 blade can be used to develop the plane between the two once identified. Tag the superior border of the medial subscap tendon flap.

Make the capsular incision vertically starting about 7-10 mm medial to the subscap insicion and expose the joint. Inferiorly, turn the blade upwards and cut away from the axillary nerve. Again, superiorly make sure there is some capsule to suture back to laterally. Insert the Fukuda humeral head retractor and expose the glenoid. Look for the Bankart lesion anteriorly. Undermine the capsule off the anterior glenoid – don’t be fooled by the capsule and labrum that have pulled off and have adhered down to the anterior glenoid. They will be adherent in an incompetent fashion, and need to be dissected off the glenoid neck. Use the cobb to peel the capsule back off the bony glenoid neck, then insert the forked retractor in to retract the capsule back and expose the anterior glenoid. Roughen up with glenoid with an osteotome and mallet. Then identify where the suture holes are going to go. Use the single tap from within the articular surface to start the hole, and connect it up with the tap on the bony side of the glenoid. There is the clamp device to

Osteochondroma

– most common benign bone tumor arising in 2nd decade
– usu distal femur, proximal tibia & proximal humerus – disordered enchondral bone growth arising from metaphyseal surface of the bone adjacent to the physis
– may be sessile or pedunculated & grow away from the physis
– risk of malignant transformation to chondrosarcoma

Reamed and Nonreamed Intramedullary Nailing on Fracture Healing

Reference: Chapman M.W., CORR, 355S pg S230-280, 1998

Main Message

– Intramedullary nailing has mechanical and biologic effects on fracture healing. The mechanical effects are known well documented; the biologic effects are less well understood (as are the implications of these on fracture healing). The molecular biologic effects have not been studied.

Points of Interest

Mechanics – influenced by nail geometry and stiffness
– geometry includes longitudinal shape, transverse diameter, cross sectional shape, slot
– stiffness influenced by material properties
– most are made of 316L stainless steel or titanium
– the modulus of elasticity of titanium is half that of stainless steel, but the ultimate strength is about 1.6 times that of stainless steel
– cross sectional area is important – moment of inertia increases by the FOURTH power of the radius, so as the diameter increases, the moment of inertia increases very quickly
– the main mechanical advantage of reaming is that a larger diameter nail can be inserted, which will be stronger, and will have a longer contact area through the isthmus

Biologic

Pulmonary Effects of Reaming
– European studies showed a large difference in pulmonary problems with reaming; these results have not been reproduced in North American studies which have showed no difference in both animal models (Schemitsch – canine model) or clinically (Bosse – retrospective study of 453 patients, Chapman – prospective study of 82 patients).

Bone Vascularization Effects of Reaming
– cortex in the mid-diaphysis receives the inner 2/3 from endosteal vessels, the outer 10-30% from the periosteum
– the larger you ream, the more the total blood flow and cortical blood flow is reduced acutely.
– a strong hyperemic reaction is induced by reaming however.
– nails that tightly fit the inner cortex interfere more with revascularization
– muscle coverage is important for increasing bone perfusion if there has been soft tissue loss (open fracture)
– both reamed and unreamed nails create a zone of avascularity within the inner part of the cortical bone. This avascular zone of the cortical bone is smaller in unreamed nails acutely and at 6 weeks, but the difference decreases in time. The differences seem to be pretty small – 51% vs 62%, 40% vs 51%.

Thoughts….
– Interesting review of the topic.