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The Journal of Bone & Joint Surgery British Volume
Vol. 73-B, Issue 3 | Pages 481 - 486
1 May 1991
Tregonning G Transfeldt E McCulloch J Macnab I Nachemson A

We reviewed two comparable groups of patients who had been treated for lumbar disc herniation by chymopapain chemonucleolysis (145) or conventional surgical discectomy (91). They were reviewed 10 years after treatment by questionnaire, followed by a personal interview by an independent observer. The results of the surgically treated groups were slightly better than those treated with chymopapain. In particular, there was significantly better early relief of leg and low back pain, and fewer patients needed a second procedure. Complications were few in both groups.

The Journal of Bone & Joint Surgery British Volume
Vol. 63-B, Issue 2 | Pages 272 - 277
1 May 1981
Kikuchi S Macnab I Moreau P

There are many difficulties associated with the localisation of the symptomatic segment in patients presenting with cervicobrachial pain with no evidence of impaired conduction in the nerve root. Ancillary radiological investigations such as myelography, epidural phlebography, and epidural myelograms are of unreliable diagnostic value. However, discography can be of value if the technique described here is used. Infiltration of the cervical nerve root with local anaesthetic has also proved useful in the localisation of the symptomatic segment. The techniques used in cervical discography and infiltration of the nerve root are described and their reliability is assessed.

The Journal of Bone & Joint Surgery British Volume
Vol. 56-B, Issue 3 | Pages 545 - 550
1 Aug 1974
LaRocca H Macnab I

1 . Standard lumbar laminectomy was performed at multiple levels in thirty dogs, and manipulations were carried out in the spinal canal to observe their effects on periradicular adhesion formation. The canal was scarified, packed with Gelfoam, or treated with three varieties of Silastic membranes. The results were serially assessed from three days to twelve weeks by gross observation, nerve conduction studies, histological examination of transverse sections of the spine, myelin study of lumbar roots and micropaque study of the arterial supply to the roots.

2. The results were consistent biologically. The principal source of scar is dorsally in the fibrous tissue elements of the erector spinae muscle mass. This scar, the laminectomy membrane, covers the laminectomy defect and extends into the canal bilaterally to adhere to the dura and nerve roots.

3. Gelfoam does not contribute to scar formation, but instead acts as an effective interposing membrane. Silastic membranes are capable of providing protection against nerve root adhesions without interfering with the anatomical or physiological integrity of the nerves.

4. Certain clinical implications of the study are discussed.

The Journal of Bone & Joint Surgery British Volume
Vol. 53-B, Issue 4 | Pages 628 - 638
1 Nov 1971
Macnab I Dall D

1. Intertransverse fusion in the lumbar spine appears to have many advantages over previously described techniques.

2. The disadvantage of profuse bleeding can be overcome by the use of a Hastings frame and by an operative technique designed to demonstrate constant muscular and articular branches of the lumbar arteries.

3. Coagulation of these vessels by cautery and avoidance of dissection anterior to the plane of the transverse processes ensure that the operative procedure can be carried out with a blood loss averaging less than 500 millilitres.

The Journal of Bone & Joint Surgery British Volume
Vol. 52-B, Issue 3 | Pages 540 - 553
1 Aug 1970
Rathbun JB Macnab I

1. The avascular zone in the tendon of the supraspinatus near its insertion was not seen in the other tendons comprising the rotator cuff, except for the superior portion of the insertion of the infraspinatus which, on occasions, showed a small avascular area. The biceps tendon, however, also showed an avascular zone as it coursed over the head of the humerus. It is suggested that the anatomical disposition of these tendons makes them subject to constant pressure from the head of the humerus, which tends to wring out the blood supply to these tendons when the arm is held in the resting position of adduction and neutral rotation.

2. Although this study did not produce any evidence that the relative avascularity of the tendons over a prolonged period could be indicted as the sole cause of the degenerative changes that so commonly occur, it was noted that the degenerative changes occurred first and that they were always most extensive in the areas of avascularity. It was also observed that the zones of relative avascularity preceded, and were not the result of, the degenerative changes.

3. With the onset of tendon degeneration, secondary vascular phenomena were observed. Firstly, there was a reaction that appeared to be a foreign body inflammatory response with the development of vascular tufts of granulation tissue. It was thought that these vascular changes were secondary to the breakdown in the tendons and were not the cause of the breakdown as previously suggested by Anderson and Moore. it was noted, moreover, that with the progression of degenerative changes in the supraspinatus tendon, the tendon became much attenuated and, as it did so, the zone of relative avascularity appeared to extend. This secondary shut-down of the vascular bed might well be caused by an increased tension in the tendon. In those tendons in which spontaneous rupture had occurred, it was noted that the major part of the tendon proximal to the rupture was avascular and showed evidence of much degenerative change. This study therefore suggests that in the operative repair of such lesions it is necessary to excise the degenerate avascular tendon in order to effect a sound repair. It is also suggested that detachment of the supraspinatus muscle from the supraspinous fossa in order to advance the whole muscle belly is the only technique possible to enable the surgeon to replace healthy tendon directly into bone, as suggested by Debeyre and his colleagues.

The Journal of Bone & Joint Surgery British Volume
Vol. 52-B, Issue 3 | Pages 524 - 527
1 Aug 1970
Weiner DS Macnab I

1. A radiological study of the acromio-humcral interval in sixty normal shoulders and in fifty-nine shoulders with known tears of the rotator cuff is reported.

2. The normal acromio-humeral interval was found to be seven to fourteen millimetres, a range that is consistent with previous observations.

3. Narrowing of this interval is a frequent concomitant of a tear of the rotator cuff.

4. An interval of five millimetres or less should be considered compatible with a tear of the rotator cuff until proven otherwise.

5. An explanation of the pathomechanics of the observation has been proposed.

The Journal of Bone & Joint Surgery British Volume
Vol. 36-B, Issue 2 | Pages 304 - 322
1 May 1954
Harris RI Macnab I

One of the interesting aspects of spinal pathology having an important bearing on the treatment of backache is that the spine acts as an integrated whole and that damage sustained by one part frequently injures other structures in the spinal column. Thus disc degeneration may be associated with an extrusion of nuclear material; it may initiate degenerative changes in the posterior joints; it may predispose to tears of the posterior spinal ligaments; or it may give rise eventually to all of these lesions, any one of which may produce backache with or without sciatica. The sciatica may be referred pain or may be produced by nerve root pressure. Nerve root pressure in such instances is commonly due to an extrusion of nuclear material, but it may also be due to pressure on the nerve root within the foramen by a "squashed" disc or by a subluxated posterior joint.

Radiographs are of great value in the diagnosis of disc degeneration and they are of greater value in the assessment of the secondary effects that have taken place. With the use of bending films evidence of early degenerative changes may be obtained, tears of the supraspinous ligament can be detected, and abnormal movements of the posterior joints can be seen. Careful study of the antero-posterior and lateral projections will reveal evidence of subluxation of the posterior joints, chip fractures and degenerative arthritis in the zygapophysial articulations, and will clearly demonstrate overriding of the facets.

The investigation of subjective phenomena, such as backache, is fraught with many difficulties and it must be preceded by an investigation of the anatomy of the part and the anatomical variations, the normal and abnormal physiology and the pathological lesions that occur. Many of these changes of course may have no clinical significance, but it is only when armed with the knowledge of what may occur that we can tackle the problem of low back pain on a logical basis.

The Journal of Bone & Joint Surgery British Volume
Vol. 34-B, Issue 3 | Pages 366 - 385
1 Aug 1952
Bonney G Macnab I

1. A survey has been made of 518 operations for hallux valgus and hallux rigidus.

2. The methods of critical examination used in this survey are described.

3. The results obtained have led to the formulation of certain views on etiology and modes of treatment.

4. In hallux valgus in the adolescent, operations aimed at correcting the primary deformity are justifiable when correctly performed, though the exact form such operations should take still requires further study.

5. In hallux valgus in the adult, arthroplasty offers a reasonably good solution in the well chosen case, though no one should consider that the results are so good as to make unnecessary any further research in this field. Metatarsal osteotomy has in the adult only a limited sphere of application.

6. In hallux rigidus arthroplasty alone has no place in the treatment of the adult cases showing metatarsus primus elevatus, nor in the adolescent case. The possibilities of other methods of operative treatment, notably osteotomy, are discussed.

The Journal of Bone & Joint Surgery British Volume
Vol. 32-B, Issue 3 | Pages 325 - 333
1 Aug 1950
MacNab I

Spondylolisthesis without a defect in the neural arch, the "pseudo-spondylolisthesis" of Junghanns, usually affects the fourth lumbar vertebra. The essential lesion is an increase in the angle between tile inferior facets and the pedicles which allows subluxation at the inferior joints. The forward displacement averages less than one centimetre.

It commonly produces a clinical picture of backache and sciatica, but may present with. a "drop foot," and in unusual instances compression of the cauda euluina may occur.

Patients seen in the early stages without signs of nerve root compression are best treated by localised spinal fusion. Late fusion may afford no relief because of secondary changes in the spine, but these patients obtain some benefit from a corset. Laminectomy is indicated for severe symptoms in patients who show signs of nerve root compression; it should be followed by spinal fusion.