- Email: [email protected]
The vascularisation of a tendon graft
T H E VASCULARISATION OF A T E N D O N GRAFT By FENTON BRAITHWAITE,O.B.E., F.R.C.S., and J. G. BROCKIS,F.R.C.S.
Department of Surgery, Royal Victoria Infirmary and Medical School, Newcastle upon Tyne INTRODUCTION THE successful use of tendon grafts in the restoration of the continuity of flexor tendons is now well established. The advances that have been achieved are the result of years of patient work by such pioneers as Bunnell and Koch. Many factors enter into the successful use of tendon grafts, and the formation of a good blood supply to the newly introduced tendon is not the least important. The work of Edwards (1946) has shown that tendons possess a blood vascular system more profuse than was hitherto realised. It is natural to expect that a tendon graft which survives becomes adequately revascularised, but the opportunity to examine the nature and manner of revascularisation rarely presents itself. It is because just such an opportunity was afforded that the following account is presented. CASE REPORT History.--As a result of a motor accident on 2oth August 1948, a man aged 28 suffered multiple lacerations of the hands and face. These were sutured elsewhere. It was subsequently found that he could not flex the little finger, and he was admitted to the Royal Victoria Infirmary, Newcastle upon Tyne, on 23rd January 195o. Operation the following day showed that both sublimis and profundus tendons to the little finger had been completely severed at the base of the finger, and were adherent to a scar in the web between the little and ring fingers and also to the metacarpal tunnel. Both adherent tendons were removed from their bony insertions up to the middle of the palm, together with the tendon sheath of the little finger, leaving behind transverse retaining bands over each joint. A free graft was taken from the long extensor of the left second toe. This was removed together with surrounding paratenon, and was threaded into place. It was sutured, by Bunnell's technique, to the terminal phalanx at the point of insertion of the profundus tendon, and to both tendons in the palm. In addition, fine silk stitches were added at both suture lines. The graft was so arranged that the wrist and finger remained in a position of moderate flexion. The patient was seen on I6th March and again on 6th April. The result was functionally excellent (Fig. i). On I3th April he was seen again, when he explained that in a rather alcoholic state he had fallen off a trolley bus and in falling had tried to grasp the rail but had managed to hold on only by his little finger. The graft had broken with the severe trauma inflicted. Economic circumstances prevented him from having a further graft, and the finger was amputated on 29th May. The graft had therefore been in position in the finger for eighteen weeks. i3o
THE
VASCULARISATION
OF
A TENDON
GRAFT
131
Method.--After amputation of the finger through the metacarpo-phalangeal joint, cannulm were inserted into the ventral digital arteries of the finger and colloidal silver iodide was injected at a controlled pressure of 15o mm. Hg.
{FIG. I H a n d six weeks after tendon graft to little finger.
.
H ~
R
y.,
FIG. 2 Cross-sectional diagram to illustrate the n o r m a l arterial and venous pattern in a tendon.
The return flow through the veins was occluded after a short time by a rubber band applied to the finger base, and the specimen then fixed in formol saline and later dissected. The flexor tendon graft together with the overlying skin
132
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
was removed and was cut into small pieces, which were immersed overnight in photographic developer. The injected vessels as a result appeared black. Longitudinal and transverse sections of the tendon were cut at a thickness of 600 ~, and were cleared in methyl salicylate and then mounted. Results.--The normal blood vascular pattern of a tendon consists of longitudinal channels of arterioles and venules lying parallel to the collagen bundles in the interfascicular connective tissue (Fig. 2). The long channels are connected by frequent cross-branches, which lie in this connective tissue (Edwards, 1946 ; Brockis, in press).
FIG. 3 Transverse section of the skin of the terminal pulp, little finger, showing the capillaries. × 13o.
Study of the sections revealed that the capillary vessels of the skin were completely filled, indicating the adequacy of the injection (Fig. 3). It was observed that the tendon graft had been revascularised throughout its length. Transverse sections were taken through the graft at the level of the proximal interphalangeal joint. In these the cut ends of many longitudinal vessels were observed lying between the collagen bundles (Figs. 4 and 5). Other vessels were demonstrated running from the subcutaneous tissue of the finger to join the longitudinal network. These vascular connections were found to be more numerous close to the insertion of the graft, and horizontal sections taken through the terminal pulp showed many such vessels (Fig. 6). Confirmation that this longitudinal vascular pattern was uniform throughout the graft was obtained by other sections taken at the level of the intermediate phalanx (Fig. 7).
THE
VASCULARISATION
OF
A TENDON
GRAFT
133
FIG. 4 T r a n s v e r s e section t h r o u g h s u b cutaneous tissue a n d t e n d o n graft at t h e level of t h e p r o x i m a l interphalangeal joint. × IOO.
FIG. 5 T r a n s v e r s e section of a portion of t h e t e n d o n graft s h o w n in Fig. 4. × 2o0.
!34
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
FIG. 6 Longitudinal section depicting vessels passing from subcutaneous tissue of terminal pulp into graft, x 12o.
FIG. 7 Transverse section of a tendon graft at the level of the intermediate phalanx. × 2oo.
THE
VASCULARISATION OF A TENDON
GRAFT
135
DISCUSSION
The results indicate that a tendon graft becomes revascularised by means of vascular connections between the graft and surrounding tissues. Such vessels enter or leave the graft throughout its length, but at the distal point of suture (into the terminal phalanx) there is an especial profusion of new vessels. The pattern of vessels within the graft is similar to the normal vascular pattern, except that it is not so profuse. SUMMARY The pattern of vascularisation within a tendon graft follows closely the original vascular pattern. The adhesions between the graft and its surrounding tissues carry the new vessels of entry.
We should like to thank Professor F. H. Bentley (in whose Department this work was carried out) for his assistance, Mr Wilson for the histology, and Messrs Ridley and Pegg of the Department of Photography, University of Durham, for the photographs.
REFERENCES EDWARDS, D. A. W. (1946). ft. Anat. Lond., 8o, 147. GARLOCK, J. H. (1927). Ann. Surg., 85, 92.
Department of Surgery, Royal Victoria Infirmary and Medical School, Newcastle upon Tyne INTRODUCTION THE successful use of tendon grafts in the restoration of the continuity of flexor tendons is now well established. The advances that have been achieved are the result of years of patient work by such pioneers as Bunnell and Koch. Many factors enter into the successful use of tendon grafts, and the formation of a good blood supply to the newly introduced tendon is not the least important. The work of Edwards (1946) has shown that tendons possess a blood vascular system more profuse than was hitherto realised. It is natural to expect that a tendon graft which survives becomes adequately revascularised, but the opportunity to examine the nature and manner of revascularisation rarely presents itself. It is because just such an opportunity was afforded that the following account is presented. CASE REPORT History.--As a result of a motor accident on 2oth August 1948, a man aged 28 suffered multiple lacerations of the hands and face. These were sutured elsewhere. It was subsequently found that he could not flex the little finger, and he was admitted to the Royal Victoria Infirmary, Newcastle upon Tyne, on 23rd January 195o. Operation the following day showed that both sublimis and profundus tendons to the little finger had been completely severed at the base of the finger, and were adherent to a scar in the web between the little and ring fingers and also to the metacarpal tunnel. Both adherent tendons were removed from their bony insertions up to the middle of the palm, together with the tendon sheath of the little finger, leaving behind transverse retaining bands over each joint. A free graft was taken from the long extensor of the left second toe. This was removed together with surrounding paratenon, and was threaded into place. It was sutured, by Bunnell's technique, to the terminal phalanx at the point of insertion of the profundus tendon, and to both tendons in the palm. In addition, fine silk stitches were added at both suture lines. The graft was so arranged that the wrist and finger remained in a position of moderate flexion. The patient was seen on I6th March and again on 6th April. The result was functionally excellent (Fig. i). On I3th April he was seen again, when he explained that in a rather alcoholic state he had fallen off a trolley bus and in falling had tried to grasp the rail but had managed to hold on only by his little finger. The graft had broken with the severe trauma inflicted. Economic circumstances prevented him from having a further graft, and the finger was amputated on 29th May. The graft had therefore been in position in the finger for eighteen weeks. i3o
THE
VASCULARISATION
OF
A TENDON
GRAFT
131
Method.--After amputation of the finger through the metacarpo-phalangeal joint, cannulm were inserted into the ventral digital arteries of the finger and colloidal silver iodide was injected at a controlled pressure of 15o mm. Hg.
{FIG. I H a n d six weeks after tendon graft to little finger.
.
H ~
R
y.,
FIG. 2 Cross-sectional diagram to illustrate the n o r m a l arterial and venous pattern in a tendon.
The return flow through the veins was occluded after a short time by a rubber band applied to the finger base, and the specimen then fixed in formol saline and later dissected. The flexor tendon graft together with the overlying skin
132
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
was removed and was cut into small pieces, which were immersed overnight in photographic developer. The injected vessels as a result appeared black. Longitudinal and transverse sections of the tendon were cut at a thickness of 600 ~, and were cleared in methyl salicylate and then mounted. Results.--The normal blood vascular pattern of a tendon consists of longitudinal channels of arterioles and venules lying parallel to the collagen bundles in the interfascicular connective tissue (Fig. 2). The long channels are connected by frequent cross-branches, which lie in this connective tissue (Edwards, 1946 ; Brockis, in press).
FIG. 3 Transverse section of the skin of the terminal pulp, little finger, showing the capillaries. × 13o.
Study of the sections revealed that the capillary vessels of the skin were completely filled, indicating the adequacy of the injection (Fig. 3). It was observed that the tendon graft had been revascularised throughout its length. Transverse sections were taken through the graft at the level of the proximal interphalangeal joint. In these the cut ends of many longitudinal vessels were observed lying between the collagen bundles (Figs. 4 and 5). Other vessels were demonstrated running from the subcutaneous tissue of the finger to join the longitudinal network. These vascular connections were found to be more numerous close to the insertion of the graft, and horizontal sections taken through the terminal pulp showed many such vessels (Fig. 6). Confirmation that this longitudinal vascular pattern was uniform throughout the graft was obtained by other sections taken at the level of the intermediate phalanx (Fig. 7).
THE
VASCULARISATION
OF
A TENDON
GRAFT
133
FIG. 4 T r a n s v e r s e section t h r o u g h s u b cutaneous tissue a n d t e n d o n graft at t h e level of t h e p r o x i m a l interphalangeal joint. × IOO.
FIG. 5 T r a n s v e r s e section of a portion of t h e t e n d o n graft s h o w n in Fig. 4. × 2o0.
!34
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
FIG. 6 Longitudinal section depicting vessels passing from subcutaneous tissue of terminal pulp into graft, x 12o.
FIG. 7 Transverse section of a tendon graft at the level of the intermediate phalanx. × 2oo.
THE
VASCULARISATION OF A TENDON
GRAFT
135
DISCUSSION
The results indicate that a tendon graft becomes revascularised by means of vascular connections between the graft and surrounding tissues. Such vessels enter or leave the graft throughout its length, but at the distal point of suture (into the terminal phalanx) there is an especial profusion of new vessels. The pattern of vessels within the graft is similar to the normal vascular pattern, except that it is not so profuse. SUMMARY The pattern of vascularisation within a tendon graft follows closely the original vascular pattern. The adhesions between the graft and its surrounding tissues carry the new vessels of entry.
We should like to thank Professor F. H. Bentley (in whose Department this work was carried out) for his assistance, Mr Wilson for the histology, and Messrs Ridley and Pegg of the Department of Photography, University of Durham, for the photographs.
REFERENCES EDWARDS, D. A. W. (1946). ft. Anat. Lond., 8o, 147. GARLOCK, J. H. (1927). Ann. Surg., 85, 92.