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The use of silicone rubber spacers in flexor tendon surgery
The Use o/ Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal
T H E USE OF SILICONE R U B B E R S P A C E R S IN F L E X O R T E N D O N SURGERY
BASIL H E L A L , London In a previous article (Helal 1969) the results of the clinical use of silicone rubber tendons in a small number of cases of ~evere flexor tendon injury, were reported. The purpose of this paper is to report a survey made of all the patients treated between 1966 and 1971, together with modifications in the technique made in the light of further experience. EXPERIMENTAL WORK
Animal experimental studies still in progress have been concerned mainly with revascularisation of tendon grafts placed in tunnels formed round silicone rubber spacers, and reveal some important facts; tendon grafts are very easily damaged if taken by tendon strippers or by avulsion, irregularities such as constriction of the walls of the pseudosheath which occur very often at bridge sites will damage these grafts and also desiccation will produce a good deal of surface damage to the graft. It is therefore recommended that the donor tendon should be removed immediately prior to being inserted into the pseudosheath. In the presence of any surface or deep damage, tendon grafts will not survive, without inducing the ingrowth of vascular granulation tissue which in turn will form adhesions. INDICATIONS FOR TREATMENT
I have confined the use of a two stage operation--firstly the silicone rubber spacer, followed ten weeks later by an autograft to those cases of damage to both tendons within the flexor sheath, in the circumstances listed below:-1. Vailed primary repair. 2. Failed graft. 3. Injury to more than 1 cm. of sheath. 4. Soft tissue loss with scarring. 5. Concurrent bone or joint injury. 6. Multiple tendon injuries. CONTRA-INDICATIONS
The only contra-indication to the procedure is joint stiffness. OPERATIVE TECHNIQUE, STAGE 1 T h e Artificial tendon. Initially silicone rubber rods threaded with silk were used but these were soon replaced by a 4 ram. silicone rubber tendon with a woven Dacron core. This artificial tendon has been used in the bulk of the cases described. It is very important not to contaminate the material by bringing it into direct contact with skin--either the surgeon's or the patient's, as sebum is removed from the silicone rubber only with the greatest difficulty. It is equally vital not to abrade the surface of the prosthesis by rough handling with surgical instruments. The Hand--Vol. 5
No. 1
1973
85
The Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal
Fig. 1
This 4mm silicone rubber tendon with a dacron core has been used in the bulk of cases described (Dow Corning experimental tendon).
Skin I n c i s i o n
I have noted that there is less morbidity in our series following the use of a mid axial incision in the finger. This is important as early passive movements are encouraged and an incision repeatedly crossing the prosthesis such as that described by Bruner (1967), whilst giving excellent exposure, is best avoided during this stage of the procedure. Skin breakdown exposing the artificial tendon will only heal after removal of the material--a fresh start has to be made after the skin has healed.
22
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'66 '67 '68 '69 '70 '71 YEAR
Fig. 2 86
The Hand--Vol. 5
No. 1
1973
The Use o[ Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal A c t i v e versus Passive tendons
I have abandoned the use of the active tendon for two reasons: Firstly, the risk of a pull off either proximally or distally is high and whereas the proximal dehiscence is of little importance, the breakdown of the distal anastomosis affects the quality of the pseudosheath produced. Secondly, when it is difficult to leave adequate bridges the passive "graft" will lie close to the bone whilst the active tendon will tend to bow string and form a tall pseudosheath. Finally the irregularity produced by the formation of artificial bridges results in adhesion at these sites and so they are best avoided. The pseudosheath formed close to bone will not result in any significant bow stringing of its contained tendon even in the absence of bridges. T h e tendon bed
I now favour the long graft (Matev 1966) to avoid anastomosis in the palm. It is quite common to find extensive reaction and adhesions in the palm almost as far as wrist level following severe tendon injuries over the proximal phalanx. Both flexors should be removed from the palm and the lumbrical muscle is detached from the profundus tendon and its muscle belly left free in the palm. The distal end of the artificial tendon is anchored to the stump of the flexor tendon. The proximal end is bedded deep to the future motor at wrist level (either superficial or deep tendon, whichever is the more "springy"), so that the future proximal anastomosis of the autograft will lie on a smooth mesothelial surface. Post-operative Stage 1
Passive movements are encouraged from the beginning and ten weeks later the second stage is carried out.
Fig. 3
This eighteen year old boy referred from another hospital had' had three previous operations for section of both flexors over the proximal phalanx of the ring finger. These were: (1) primary repair, (2) flexor tendon graft, (3) tenolysis. His artificial tendon was inserted one year after his most recent previous operation. The picture was taken three months after completion of the second stage.
The Hand--Vol. 5
No. 1
1973
87
The Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal
Fig. 4
This forty-five year old baker, sectioned the flexor apparatus over the proximal phalanges in the ulnar three digits of his hand, when he was cutting dough and his hand slipped off the handle of the knife onto the blade. Photographed five months after completion of the second stage.
OPERATIVE TECHNIQUE, STAGE 2
Palmaris or plantaris (or if multiple tendons are required, fascia lata strips can be used) are rail-roaded through the tunnel or pseudosheath formed round the silicone rubber tendon, by attachment to the artificial tendon before it is withdrawn. If adequate pistoning has occurred then a pseudosheath with a substantial wall is formed. If there has been little in the way of movement of the prosthesis then very often the pseudosheath is very thin and contains frondy synovial material sometimes containing milky fluid which on analysis appears to contain quite a large amount of fat. This is no contra-indication to proceeding with the second stage. Hunter (1971) has suggested a useful manoeuvre to judge the tension of the graft, namely that the second stage is carried out under local anaesthesia and the conscious patient can then voluntarily flex and extend the finger so that the length of the graft can be adjusted to perfection. This is a useful manoeuvre in a phlegmatic patient, but may create difficulties for the very young or the nervous patient. Post~operative Stage 2
Protected flexion is begun at three weeks and active extension started at five weeks. RESULTS TABLE 1
Total n u m b e r s o f patients treated
Lost to follow-up - - 4 Total available for study Total
88
1 3 6 52
--
62
child adults children adults
58
The Hand--Vol. 5
No. 1
1973
Tile Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal TABLE 2 A R T I F I C I A L T E N D O N SPACER O P E R A T I O N S
No. o/digits 8 4 3 2
No. o/ patients 1 4 1 4 Digits 10 48 Total
35 48
58
Total
83
TABLE 3 FINGERS INVOLVED
Thumb 2
Index
Middle
Ring
Little
Total
26
21
16
16
83
TABLE 4 CRITERIA F O R A S S E S S M E N T
Fingers:
Good: Fair:
Poor." Good." Fair." Poor:
Thumb:
P u l p l i n . a w a y or n e a r e r to distal crease of palm. C o m b i n e d loss of e x t e n s i o n less t h a n 40 ° . P u l p to p a l m lin. or m o r e f r o m distal p a l m a r crease. C o m b i n e d loss of extension less t h a n 60 ° . P u l p fails to touch palm. C o m b i n e d loss of extension m o r e t h a n 60 ° . 45 ° to full flexion. 0 - 45 °. Will n o t support a pinch.
TABLE S RESULTS Fair: 4 6
Good: 33
The Hand--Vol. 5
No. 1
1973
Poor: 4 89
The Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal Complications Stage 1
3 - - Infection resulting in removal of spacers. 6 - - Distal detachment of silicone rubber rod. - - all "active" tendons. Complications Stage 2
The "frozen graft"---this has occurred in four cases and I believe has been due to damage of the donor tendon. TABLE 6 ANALYSIS
Donor tendon damaged
OF POOR RESULTS
2 poor technique on removal. 1 accidentally put into spirit. 1 infection.
I have always been able to persuade patients with complications in Stage 1 to allow me to start again. However, I have never been able to persuade patients to do this for complications in Stage 2. Features improving results
1. 2. 3. 4. 5.
Mid-axial incisions. Long graft. Passive tendon--distal attachment only. No artificial bridges. Local anaesthetic in Stage 2. SUMMARY
Further experience with the use of silicone rubber tendons has encouraged their wider use in the repair of difficult injuries of the flexor apparatus. I have surveyed all such patients treated by this method up until the end of 1971. Attention to detail and especially to the meticulous avoidance of damage to the donor tendon for the graft, will improve the results.
REFERENCES
BRUNER, I. M. (1967). The Zig-Zag Volar Digital Incision for Flexor Tendon Surgery. The British Club for Surgery of the Hand, Proceedings Vienna Meeting, p. 33-34. HELAL, B. (1969). Silastics in Tendon Surgery. The Hand, 1: 120-121. HUNTER, J. M. (1965). Artificial Tendons. Their Early Development and Application. Journal of Bone and Joint Surgery, 47A: 631-632. HUNTER, J. M. and SALISBURY, R. E. (1971). Flexor-Tendon Reconstruction in Severely Damaged Hands. Journal of Bone and Joint Surgery, 53A; 829-858. MATEV, I. (1966). Flexor Tendon Grafting with Ufilisation of Long Grafts from the Wrist to the End Phalanx. The British Club for Surgery of the Hand, May 1966, 24-25. 90
The Hand--Vol. 5
No. 1
1973~
T H E USE OF SILICONE R U B B E R S P A C E R S IN F L E X O R T E N D O N SURGERY
BASIL H E L A L , London In a previous article (Helal 1969) the results of the clinical use of silicone rubber tendons in a small number of cases of ~evere flexor tendon injury, were reported. The purpose of this paper is to report a survey made of all the patients treated between 1966 and 1971, together with modifications in the technique made in the light of further experience. EXPERIMENTAL WORK
Animal experimental studies still in progress have been concerned mainly with revascularisation of tendon grafts placed in tunnels formed round silicone rubber spacers, and reveal some important facts; tendon grafts are very easily damaged if taken by tendon strippers or by avulsion, irregularities such as constriction of the walls of the pseudosheath which occur very often at bridge sites will damage these grafts and also desiccation will produce a good deal of surface damage to the graft. It is therefore recommended that the donor tendon should be removed immediately prior to being inserted into the pseudosheath. In the presence of any surface or deep damage, tendon grafts will not survive, without inducing the ingrowth of vascular granulation tissue which in turn will form adhesions. INDICATIONS FOR TREATMENT
I have confined the use of a two stage operation--firstly the silicone rubber spacer, followed ten weeks later by an autograft to those cases of damage to both tendons within the flexor sheath, in the circumstances listed below:-1. Vailed primary repair. 2. Failed graft. 3. Injury to more than 1 cm. of sheath. 4. Soft tissue loss with scarring. 5. Concurrent bone or joint injury. 6. Multiple tendon injuries. CONTRA-INDICATIONS
The only contra-indication to the procedure is joint stiffness. OPERATIVE TECHNIQUE, STAGE 1 T h e Artificial tendon. Initially silicone rubber rods threaded with silk were used but these were soon replaced by a 4 ram. silicone rubber tendon with a woven Dacron core. This artificial tendon has been used in the bulk of the cases described. It is very important not to contaminate the material by bringing it into direct contact with skin--either the surgeon's or the patient's, as sebum is removed from the silicone rubber only with the greatest difficulty. It is equally vital not to abrade the surface of the prosthesis by rough handling with surgical instruments. The Hand--Vol. 5
No. 1
1973
85
The Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal
Fig. 1
This 4mm silicone rubber tendon with a dacron core has been used in the bulk of cases described (Dow Corning experimental tendon).
Skin I n c i s i o n
I have noted that there is less morbidity in our series following the use of a mid axial incision in the finger. This is important as early passive movements are encouraged and an incision repeatedly crossing the prosthesis such as that described by Bruner (1967), whilst giving excellent exposure, is best avoided during this stage of the procedure. Skin breakdown exposing the artificial tendon will only heal after removal of the material--a fresh start has to be made after the skin has healed.
22
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17 ;.::-:::-:~ ........., ~===.~ •. • q °.'.'.'.', ~%'.'.%' , : . : . : . : , 1
No:
::::::::': :_':_':_':_':1
Of
i!ii!iiiii:.:.:.:.~
11 ......... ....... -:i:i$! :':::::-~
Patients
'°°.°.' ,.**..,
'.'.'°°.°, ~;_%_%_%~1
'°°o°.' '°*.'.' '°°'°" ,...*.,
'°°o°°'°°, 'o.'°.'..'.'1 '.'.'*'*', [.Z*.'..'*:I '°°°°°°°°' ;?'_-'-:'-!7t ,........, ,:o_.:*:q • ***°.° ,°°****°°, ,2.~°2.211
4
%%%= ,.°.°.°°°, ,2°i.2.211 ,z*2*~0 ,.°.°O°l °, ,212-2°211 '*°*°°°*°' °i-i-i*2,,I
i!ilil
'*'*'*" ,:.1.:.:°1 '*****°**' ,:*:*:*:ol ," ,*,°. *, ,", . , , ,: .:*:*:,,I .........
'66 '67 '68 '69 '70 '71 YEAR
Fig. 2 86
The Hand--Vol. 5
No. 1
1973
The Use o[ Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal A c t i v e versus Passive tendons
I have abandoned the use of the active tendon for two reasons: Firstly, the risk of a pull off either proximally or distally is high and whereas the proximal dehiscence is of little importance, the breakdown of the distal anastomosis affects the quality of the pseudosheath produced. Secondly, when it is difficult to leave adequate bridges the passive "graft" will lie close to the bone whilst the active tendon will tend to bow string and form a tall pseudosheath. Finally the irregularity produced by the formation of artificial bridges results in adhesion at these sites and so they are best avoided. The pseudosheath formed close to bone will not result in any significant bow stringing of its contained tendon even in the absence of bridges. T h e tendon bed
I now favour the long graft (Matev 1966) to avoid anastomosis in the palm. It is quite common to find extensive reaction and adhesions in the palm almost as far as wrist level following severe tendon injuries over the proximal phalanx. Both flexors should be removed from the palm and the lumbrical muscle is detached from the profundus tendon and its muscle belly left free in the palm. The distal end of the artificial tendon is anchored to the stump of the flexor tendon. The proximal end is bedded deep to the future motor at wrist level (either superficial or deep tendon, whichever is the more "springy"), so that the future proximal anastomosis of the autograft will lie on a smooth mesothelial surface. Post-operative Stage 1
Passive movements are encouraged from the beginning and ten weeks later the second stage is carried out.
Fig. 3
This eighteen year old boy referred from another hospital had' had three previous operations for section of both flexors over the proximal phalanx of the ring finger. These were: (1) primary repair, (2) flexor tendon graft, (3) tenolysis. His artificial tendon was inserted one year after his most recent previous operation. The picture was taken three months after completion of the second stage.
The Hand--Vol. 5
No. 1
1973
87
The Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal
Fig. 4
This forty-five year old baker, sectioned the flexor apparatus over the proximal phalanges in the ulnar three digits of his hand, when he was cutting dough and his hand slipped off the handle of the knife onto the blade. Photographed five months after completion of the second stage.
OPERATIVE TECHNIQUE, STAGE 2
Palmaris or plantaris (or if multiple tendons are required, fascia lata strips can be used) are rail-roaded through the tunnel or pseudosheath formed round the silicone rubber tendon, by attachment to the artificial tendon before it is withdrawn. If adequate pistoning has occurred then a pseudosheath with a substantial wall is formed. If there has been little in the way of movement of the prosthesis then very often the pseudosheath is very thin and contains frondy synovial material sometimes containing milky fluid which on analysis appears to contain quite a large amount of fat. This is no contra-indication to proceeding with the second stage. Hunter (1971) has suggested a useful manoeuvre to judge the tension of the graft, namely that the second stage is carried out under local anaesthesia and the conscious patient can then voluntarily flex and extend the finger so that the length of the graft can be adjusted to perfection. This is a useful manoeuvre in a phlegmatic patient, but may create difficulties for the very young or the nervous patient. Post~operative Stage 2
Protected flexion is begun at three weeks and active extension started at five weeks. RESULTS TABLE 1
Total n u m b e r s o f patients treated
Lost to follow-up - - 4 Total available for study Total
88
1 3 6 52
--
62
child adults children adults
58
The Hand--Vol. 5
No. 1
1973
Tile Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal TABLE 2 A R T I F I C I A L T E N D O N SPACER O P E R A T I O N S
No. o/digits 8 4 3 2
No. o/ patients 1 4 1 4 Digits 10 48 Total
35 48
58
Total
83
TABLE 3 FINGERS INVOLVED
Thumb 2
Index
Middle
Ring
Little
Total
26
21
16
16
83
TABLE 4 CRITERIA F O R A S S E S S M E N T
Fingers:
Good: Fair:
Poor." Good." Fair." Poor:
Thumb:
P u l p l i n . a w a y or n e a r e r to distal crease of palm. C o m b i n e d loss of e x t e n s i o n less t h a n 40 ° . P u l p to p a l m lin. or m o r e f r o m distal p a l m a r crease. C o m b i n e d loss of extension less t h a n 60 ° . P u l p fails to touch palm. C o m b i n e d loss of extension m o r e t h a n 60 ° . 45 ° to full flexion. 0 - 45 °. Will n o t support a pinch.
TABLE S RESULTS Fair: 4 6
Good: 33
The Hand--Vol. 5
No. 1
1973
Poor: 4 89
The Use of Silicone Rubber Spacers in Flexor Tendon Surgery--Basil Helal Complications Stage 1
3 - - Infection resulting in removal of spacers. 6 - - Distal detachment of silicone rubber rod. - - all "active" tendons. Complications Stage 2
The "frozen graft"---this has occurred in four cases and I believe has been due to damage of the donor tendon. TABLE 6 ANALYSIS
Donor tendon damaged
OF POOR RESULTS
2 poor technique on removal. 1 accidentally put into spirit. 1 infection.
I have always been able to persuade patients with complications in Stage 1 to allow me to start again. However, I have never been able to persuade patients to do this for complications in Stage 2. Features improving results
1. 2. 3. 4. 5.
Mid-axial incisions. Long graft. Passive tendon--distal attachment only. No artificial bridges. Local anaesthetic in Stage 2. SUMMARY
Further experience with the use of silicone rubber tendons has encouraged their wider use in the repair of difficult injuries of the flexor apparatus. I have surveyed all such patients treated by this method up until the end of 1971. Attention to detail and especially to the meticulous avoidance of damage to the donor tendon for the graft, will improve the results.
REFERENCES
BRUNER, I. M. (1967). The Zig-Zag Volar Digital Incision for Flexor Tendon Surgery. The British Club for Surgery of the Hand, Proceedings Vienna Meeting, p. 33-34. HELAL, B. (1969). Silastics in Tendon Surgery. The Hand, 1: 120-121. HUNTER, J. M. (1965). Artificial Tendons. Their Early Development and Application. Journal of Bone and Joint Surgery, 47A: 631-632. HUNTER, J. M. and SALISBURY, R. E. (1971). Flexor-Tendon Reconstruction in Severely Damaged Hands. Journal of Bone and Joint Surgery, 53A; 829-858. MATEV, I. (1966). Flexor Tendon Grafting with Ufilisation of Long Grafts from the Wrist to the End Phalanx. The British Club for Surgery of the Hand, May 1966, 24-25. 90
The Hand--Vol. 5
No. 1
1973~