Yoshiro Kiyoshige, Hiroyuki Tsuchida, Makoto Hamasaki, Makoto Takayanagi, and Yoshihiro Watanabe
CO 2 LASER-ASSISTED MICROVASCULAR ANASTOMOSIS: BIOMECHANICAL STUDIES AND Downloaded by: University of British Columbia. Copyrighted material.
CLINICAL APPLICATIONS ABSTRACT Experiments have been performed using CO2 laser-assisted microvascular anastomoses, and they demonstrated the following features, in comparison with conventional anastomoses: ease in technique-, less time consumption; less tissue inflammation; early wound healing; equivalency of patency rate and inner pressure tolerance; but only about 50 percent of the tensile strength of manual-suture anastomosis. Six clinical applications in 16 vessels are reported, using this procedure. The preliminary results of these cases would appear to be the first successful replantations and free tissue transfers using CO2 laserassisted microvascular anastomoses in man. The procedure offers increased safety and speed in microvascular anastomoses.
In the past, manual suturing has been the general method used for vascular anastomosis, and it requires a high level of technical skill, especially in cases of microvascular anastomosis. We have conducted a series of tests on a new method of microvascular anastomoses, using a low-output CO2 laser, that can easily be performed by any practitioner to replicate our results. Features of the method are clarified below. In addition, the first successful clinical applications of CO2 laserassisted microvascular anastomoses in hand surgery for digital replantation and free tissue transfer, are reported.
MATERIALS AND METHODS The CO2 laser unit used in the experiments and clinical applications was produced by Chugai Pharma-
ceutical Co. and the Tohoku Ricoh applied Electronics Research Center. Its oscillation wavelength is 10.6 jjun and its irradiation output can be varied from 20 to 80 mW. An He-Ne laser beam that matches both beam axis and focal point at a focus spot of 0.2 mm and focal length of 127 ms is used as a guide. An OPMI-99 model surgical microscope made by the Zeiss Company was mounted on the unit and linked to the CO2 laser manipulator. Three stay sutures were first applied at 120-degree intervals with 10-0 nylon; then, two adjacent stay sutures were made in the opposite direction to coapt the vascular stumps, and the laser beam was exposed across the interface. We observed that after part of the tunica externa and tunica media liquefied subsequent to the beam, they then gradually hardened. This interval lasted about 2 or 3 sec, and the stay sutures remained in place. The CO2 laser beam was applied in a similar fashion to the remaining two-thirds of the cir-
Departments of Orthopaedic Surgery, Yamagata Saisei Hospital and Yamagata University, Yamagata, lapan Materials in this paper were presented at the Fourth International Congress, International Federation of Societies for Surgery of the Hand, Tel-Aviv, Israel, April 10, 1989 Reprint requests-. Dr. Kiyoshige, Dept. of Orthopaedic Surgery, Yamagata Saisei Hospital, 2-3-1 Koshirakawa-machi, Yamagata City 990, lapan Accepted for publication January 15,1991 Copyright © 1991 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
225
JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 7, NUMBER 3 JULY 1991
RESULTS HISTOLOGIC FINDINGS. Among changes over postoperative time in the anastomosed vascular tissue, hyaline necrosis of the irradiated portions was noted immediately after laser application. In comparison to the manual method, inflammatory cells or fibroblasts appeared earlier and tissue regeneration was observed to occur smoothly. However, the effect of the laser beam did not reach the intima. Another distinctive feature of the laser method is that, since it involves fewer sutures, the appearance of giant foreign-body cells or inflammations, often witnessed with the manual method, was far less frequent. PATENCY RATE AND REQUIRED TIME. Comparisons between patency rates and the time required for performance, carried out immediately after vascular anastomosis, between suturing by the CO2 laser and manually, showed no significant difference in the patency rate of arteries and veins in either group. But it was evident that the time required for anastomosis with the laser procedure was less than with the manual procedure (Table 1). MECHANICAL STRENGTH. The time-course changes in inner pressure tolerance and tensile strength of portions of the vascular anastomosis and suturing were compared in the laser and manual procedures. (The safety of the laser procedure was also investigated.) \nner Pressure Tolerance of the Anastomosed Vessel. Using
orthogonal layout L32 (231), irradiation conditions (irradiation output/irradiation time) were set at four levels (Table 2). [Note-. When an orthogonal layout is used in analysis of a multifactorial design, highly accurate results can be obtained from only a fraction of the experiments. When all combinations of n factor are
Table 1.
Patency Rate and Anastomosis Time
Patency Rate (No.) Laser Manual
Artery Vein Artery Vein
Table 2. Irradiation Time
B, B2 B3 226
Figure 1. Procedure of CO2 laser-assisted microvascular anastomosis.
(42) (42) (42) (42)
Anastomosis Time 95% 86% 96% 89%
15 19 18 25
min min min min
Irradiation Condition 5 28 33 0
sec 35mW 15 sec sec 30mW 15 sec
sec sec
Level Values (Inner Pressure Tolerance) Irradiation Power (mW) A, = 31
A2 = 38
A3 = 45
6 12 18 24
5.5 10 14.5 19
8 11 14
Values shown are seconds.
5
A4 == 53 45 6 7 .5 9
Downloaded by: University of British Columbia. Copyrighted material.
cumference, until the anastomosis was completed (Fig. 1). The basic factor in successful laser anastomosis is the same as in the manual approach, i.e., correct adaptation of the vascular intima. Also, of course, the stump must not be allowed to curl up inside the intima. An important point to remember in using the laser method is that, when stay sutures have been made in opposite directions, they must be applied slightly distant from the stump, so that adequate adaptation of the intima can be achieved. Another point is that during the period of hardening after tissue liquefaction by the laser beam, the stay sutures must be left in place. Otherwise, adaptation of the intima will be retarded and welding will take place, with a portion of the tunica externa and tunica media left extended; this, in turn, can easily cause an aneurysm or other defect. Similarly, failure can result, if adaptation of the vascular stump (especially the intima) is not obtained when the tension is adequate and the stay sutures have been taken in the opposite direction. Comparisons were carried out between the two methods by histologic examination, evaluation of patency rates and time required, and mechanical and tensile strength.
LASER-ASSISTED MICROANASTOMOSIS/KIYOSHIGE, TSUCHIDA, HAMASAKI, ET AL.
Downloaded by: University of British Columbia. Copyrighted material.
Table 3. Level Values (Tensile Strength) made at the M standard, a combination different from Mn can be established. However, if the combination of Irradiation Power (mW) Mn-1, corresponding to 1/M, is selected effectively Irradiation Time A 2 = 52 A, = 45 using orthogonal layout LMn-1, the same accuracy can 11 7.5 B, be obtained as when an experiment on Mn has been B 14 9 2 performed.) Optimum irradiation conditions were deValues shown are seconds. termined, and the time-course changes in inner-pressure tolerance of the anastomosed vessel under these conditions were compared with those of the manuallysutured vessel. Preliminary tests at 24 mW and 59 mW were conducted before the experiment. The four levels were established because anastomosis was impossible at and three days, six days, and nine days thereafter. A 24 mW even when the irradiation time was prolonged, strain gauge was used to measure tensile strength. The and at 59 mW because of large tissue lesions. An point at which part of the anastomosed vessel ruparterial segment of about 10 mm, including the anasto- tured and the strength dropped sharply was taken as mosed vessel, was removed immediately after anasto- the maximum tensile strength. mosis and one day, three days and seven days later. A It was thus determined that the optimal irradiabiopump was used to apply pressure to the anasto- tion conditions from the standpoint of tensile strength mosed vessel; the pressurized condition was meas- were an output at 45 mW and an irradiation time of 14 ured by pressure sensor; and the peak pressure imme- sec. The time-course changes in tensile strength under diately before part of the vessel ruptured and internal these conditions are shown in Figure 3 for both the pressure dropped sharply, was taken as the maximum laser and manual procedures. Similar time-course inner pressure tolerance. As a result, it was determined changes were exhibited by both groups, but the laser that the optimum irradiation conditions were a 52-mW group values were about half those of the manual irradiation output and 9 sec of irradiation time. The group. time-course changes in inner pressure tolerance under As a result, it was demonstrated that laser-assisted these conditions, with both the laser and manual pro- anastomosis had the following features, compared cedures, are shown in Figure 2. Similar time-course with manual suturing, and only three sutures are rechanges were exhibited by both procedures, and no quired (Table 4): 1. easier technique; 2. Less time resignificant differences were noted. quired for anastomosis; 3. less inflammatory reaction Tensile Strength. Based on the irradiation conditionsof tissue; 4. rapid tissue redegeneration; 5. no differfor inner pressure tolerance, irradiation output and ence in patency rate; and 6. no difference in internal irradiation time were each set at two-level values (Ta- pressure tolerance of the anastomosed vessel. The ble 3) from orthogonal layout L16 (215). An arterial major drawback of the laser procedure was that within segment of about 10 mm, including the anastomosed nine days after surgery, the tensile strength was about vessel, was removed immediately after anastomosis, half the value of that in the manual procedure.
v mmHg
6000 5000 4000
C o n t r o l (Manual method)
3000 2000 1000
500 400 300 200 100
C, C 2
immediately
I day
C3 3 day
C: 7 day
C,
C2
immediately
I day
C3 3 day
7 day postoperatively
Figure 2. The time-course changes in inner pressure tolerance. There is no significant difference between the laser procedure and the manual procedure.
227
JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 7, NUMBER 3
JULY 1991
200 Control
100
50 40 30 20
l0 L 3 days
6 days
9 days
postoperatively
Table 4.
Features of CO, Laser Procedure Easy to perform Less time-consuming Less tissue inflamation Easy wound healing Patency rate Inner pressure tolerance Tensile strength
Advantage
Disadvantage
CLINICAL APPLICATIONS The results of basic research on microvascular anastmosis using a CO2 laser, as described above, indicated that the laser procedure is in no way inferior to the manual procedure, if careful attention is paid to the tension of the anastomosed vessel. A CO2 laser was used in hand surgery for vascular anastomosis of 16 vessels (0.3 to 2.0 mm), done in six cases. Among these there were two cases of revascularization, three cases
Table 5. Case
Age
Sex
Revascularization 1 28 M 2 39 F Replantation 3 18 4 5
228
44 57
M M M
of replantation involving four digits, and one case of free-tissue transfer (Table 5). One of these cases involving replantation of a single digit was unsuccessful because the flow from the proximal artery was defective. CASE 1 (revascularization): A 28-year-old male suffered an injury when his right hand was caught in a drilling machine. The extensor tendon and the radial neurovascular bundle of the middle and ring fingers were torn and the index finger was severed incompletely, with about 3 mm of dorsal skin remaining over about 5 mm proximal to the PIP joint. Since the head of the proximal phalanx of the index finger was severed completely, osteosynthesis was performed without bone shortening, and thereafter, all tissues were restored. Three stay sutures were applied to the index finger radial indicis artery, with the PIP joint flexed at about 30 degrees, and a CO2 laser beam was irradiated between the sutures for anastomosis. However, when the microclamp was removed, part of the anastomosed
Clinical Applications
Injured Digit
Anstomosed Vessel
Right index Left ring
Rad. dig. artery Rad. dig. artery
1 yr 4 mo 4 mo
Right thumb Palm Right long Left index Left long
Rad. dig. artery, dorsal vein Superficial palm . arch Bilat • dig;. artery, two dorsal veins Rad. dig. artery, dorsal vein Rad. dig. artery, dorsal vein
1 yr 4 mo
Free-tissue transfer 6 52 M Right thumb (wrap-around flap)
1st metatarsal artery -> rad. artery (snuff box) Two branches of saph vein —* two branches of saph vein
Follow-up Period
9 mo 7 mo Failed 7 mo
Downloaded by: University of British Columbia. Copyrighted material.
immediately
Figure 3. The time-course changes of tensile strength. The values of the laser procedure are about 50 percent those of the manual procedure.
LASER-ASSISTED MICROANASTOMOSIS/KIYOSHIGE, TSUCHIDA, HAMASAKI, ET AL.
about 5 mm, one ulnar digital artery and one dorsal vein were anastomosed with CO2 laser. No tension of the anastomosed vessels was noted as vascular anastomosis was carried out in conjunction with bone shortening. We believe this to be the first case of replantation by CO2 laser-assisted vascular anastomosis, based on an exhaustive search of the literature (Fig. 5). CASE 6. (free tissue transfer case): A 51-year-old male underwent replantation surgery after all digits of the right hand had been amputated. He later underwent thumb reconstruction with an abdominal wall flap after his thumb began to show necrosis. A wraparound toe-to-thumb transfer, a method of compound free-tissue transfer from the big toe with nerves and nail included, was performed subsequently in order to restore sensation and functional shape. In the "snuffbox" region, the radial artery and the first metatarsal artery were anastomosed by CO2 laser, as well as two
Downloaded by: University of British Columbia. Copyrighted material.
vessel opened, and the radial indicis artery was dissected once again proximally and distally; the PIP joint wasflexedstill further; tension was reduced; and CO2 laser-assisted anastomosis was performed. An angiogram taken two months after surgery indicated that circulation was favorable with no constriction of the anastomosed vessel. One year and three months after surgery, the PIP joint range of motion was favorable with -20 degrees extension and 80 degrees flexion. No change in circulation due to finger motion was noted (Fig. 4). CASE 3. (replantation): An 18-year-old male suffered an injury when his right hand was caught in an electric power saw. All the tissues of the palm, except for the flexor digitorum profundus tendons, were torn, and the thumb was amputated at the distal phalangeal base. After CO2 laser-assisted anastomosis was performed on the superficial palmar arch, and after IPjoint arthrodesis with shortening of the thumb by
Figure 4. Case 1. a, Incomplete amputation of right indexfinger,b, Appearance at 16 months postoperatively. c, Postoperative angiogram at eight weeks showing a patent anastomosis.
V
b c Figure 5. Case 3. a, b, Complete amputation of right thumb, c, Complete survival of replanted thumb.
229
JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 7, NUMBER 3
JULY 1991
branches of the saphenous vein and two dorsal veins of the hand. Six months after surgery, sensation was restored favorably, and the reconstructed thumb could be used satisfactorily in functional terms. As far as we know, this is the first case in man in which a CO2 laser was used for free tissue transfer (Fig. 6).
DISCUSSION In our first case, there was much concern about tensile strength, but in the later cases, the tension of the anastomosis was reduced by such methods as bone shortening. In cases of free-tissue transfer (such as Case 6), since an appropriate tension can be established at the outset, we assume that problems of tensile strength can be adequately resolved in such clinical applications. In cases of multiple vascular anastomosis (e.g., Cases 4 and 5), the operation time can be reduced, compared with the conventional manual suturing procedure. The laser procedure is especially effective because, with only three stay sutures in the soft tissue of the veins, there is less damage to the vascular walls. In contrast to conventional manual suturing the new laser-assisted procedure enables anastomosis with only three stay sutures: it would be difficult to obtain favorable patency with so few sutures, using the conventional method. In view of its advantages, therefore, the new laser-assisted method can be expected to prove extremely useful in cases such as pediatric vascular anastomosis in which the vascular diameter is
230
narrow, in replantation of severed finger tips, or in minor tissue grafts.
SELECTED REFERENCES Freeman RH, Gordon jA: Microsurgical anastomosis using a CO2 laser: A preliminary report. Conference on Laser and Electro-Optics 60, 1982 Jain KK, Gorisch W: Repair of small blood vessels with the neodymium-YAG laser: Preliminary report. Surgery 85:684, 1979 Jain KK: Sutureless extra-intra-cranial anastomosis by laser. Lancet 816:, 1984 Kiyoshige Y: Microvascular anastomosis of rat femoral arteries with the CO2 laser: The effect of dynamic intensity of the anastomosed site against internal pressure. ) Jpn Soc Surg Hand 3:987, 1987 Kiyoshige Y: Microvascular anastomosis of rat femoral arteries with the CO2 laser: Chronological observation on tensile strength. I Ipn Soc Surg Hand 3:997, 1987 Oishi I: Microvascular anastomosis with a low-output carbon dioxide laser. I. Laser device, techniques, and conditions of anastomosis. I Ipn Orthop Assoc 60:801, 1986 Oishi J; Microvascular anastomosis with a low-output carbon dioxide laser. II. Histopathological features. J Ipn Orthop Assoc 60:813, 1986 Okada M, Simizu K, Ikuta H: An alternative method of vascular anastomosis by laser: Experimental and clinical study. Laser Surg Med 7:240, 1987 Serure A, Withers EH, Thomson S, et al.: Comparison of carbon dioxide laser-assisted microvascular anastomosis and conventional microvascular sutured anastomosis. Surg Forum 34:634, 1983 Takayanagi M, Watanabe Y, Kiyoshige Y, et al.: Experimental study of micro-vascular anastomosis using CO2 laser. I Ipn Soc Surg Hand 2:693, 1985 Vale BH, Frenkel AMS, Trenka-Benthin S, et ah. Microsurgical anastomosis of rat carotid arteries with CO2 laser. Plast Reconstr Surg 177:759, 1986
Downloaded by: University of British Columbia. Copyrighted material.
Figure 6. Case 6. a, Amputation of all of right digits, b, Appearance of the reconstructed thumb by pedicle groin flap. The fingers suvived. c, Free vascularized wraparound flap from right big toe. d, Complete survival of free flap.
CO 2 LASER-ASSISTED MICROVASCULAR ANASTOMOSIS: BIOMECHANICAL STUDIES AND Downloaded by: University of British Columbia. Copyrighted material.
CLINICAL APPLICATIONS ABSTRACT Experiments have been performed using CO2 laser-assisted microvascular anastomoses, and they demonstrated the following features, in comparison with conventional anastomoses: ease in technique-, less time consumption; less tissue inflammation; early wound healing; equivalency of patency rate and inner pressure tolerance; but only about 50 percent of the tensile strength of manual-suture anastomosis. Six clinical applications in 16 vessels are reported, using this procedure. The preliminary results of these cases would appear to be the first successful replantations and free tissue transfers using CO2 laserassisted microvascular anastomoses in man. The procedure offers increased safety and speed in microvascular anastomoses.
In the past, manual suturing has been the general method used for vascular anastomosis, and it requires a high level of technical skill, especially in cases of microvascular anastomosis. We have conducted a series of tests on a new method of microvascular anastomoses, using a low-output CO2 laser, that can easily be performed by any practitioner to replicate our results. Features of the method are clarified below. In addition, the first successful clinical applications of CO2 laserassisted microvascular anastomoses in hand surgery for digital replantation and free tissue transfer, are reported.
MATERIALS AND METHODS The CO2 laser unit used in the experiments and clinical applications was produced by Chugai Pharma-
ceutical Co. and the Tohoku Ricoh applied Electronics Research Center. Its oscillation wavelength is 10.6 jjun and its irradiation output can be varied from 20 to 80 mW. An He-Ne laser beam that matches both beam axis and focal point at a focus spot of 0.2 mm and focal length of 127 ms is used as a guide. An OPMI-99 model surgical microscope made by the Zeiss Company was mounted on the unit and linked to the CO2 laser manipulator. Three stay sutures were first applied at 120-degree intervals with 10-0 nylon; then, two adjacent stay sutures were made in the opposite direction to coapt the vascular stumps, and the laser beam was exposed across the interface. We observed that after part of the tunica externa and tunica media liquefied subsequent to the beam, they then gradually hardened. This interval lasted about 2 or 3 sec, and the stay sutures remained in place. The CO2 laser beam was applied in a similar fashion to the remaining two-thirds of the cir-
Departments of Orthopaedic Surgery, Yamagata Saisei Hospital and Yamagata University, Yamagata, lapan Materials in this paper were presented at the Fourth International Congress, International Federation of Societies for Surgery of the Hand, Tel-Aviv, Israel, April 10, 1989 Reprint requests-. Dr. Kiyoshige, Dept. of Orthopaedic Surgery, Yamagata Saisei Hospital, 2-3-1 Koshirakawa-machi, Yamagata City 990, lapan Accepted for publication January 15,1991 Copyright © 1991 by Thieme Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
225
JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 7, NUMBER 3 JULY 1991
RESULTS HISTOLOGIC FINDINGS. Among changes over postoperative time in the anastomosed vascular tissue, hyaline necrosis of the irradiated portions was noted immediately after laser application. In comparison to the manual method, inflammatory cells or fibroblasts appeared earlier and tissue regeneration was observed to occur smoothly. However, the effect of the laser beam did not reach the intima. Another distinctive feature of the laser method is that, since it involves fewer sutures, the appearance of giant foreign-body cells or inflammations, often witnessed with the manual method, was far less frequent. PATENCY RATE AND REQUIRED TIME. Comparisons between patency rates and the time required for performance, carried out immediately after vascular anastomosis, between suturing by the CO2 laser and manually, showed no significant difference in the patency rate of arteries and veins in either group. But it was evident that the time required for anastomosis with the laser procedure was less than with the manual procedure (Table 1). MECHANICAL STRENGTH. The time-course changes in inner pressure tolerance and tensile strength of portions of the vascular anastomosis and suturing were compared in the laser and manual procedures. (The safety of the laser procedure was also investigated.) \nner Pressure Tolerance of the Anastomosed Vessel. Using
orthogonal layout L32 (231), irradiation conditions (irradiation output/irradiation time) were set at four levels (Table 2). [Note-. When an orthogonal layout is used in analysis of a multifactorial design, highly accurate results can be obtained from only a fraction of the experiments. When all combinations of n factor are
Table 1.
Patency Rate and Anastomosis Time
Patency Rate (No.) Laser Manual
Artery Vein Artery Vein
Table 2. Irradiation Time
B, B2 B3 226
Figure 1. Procedure of CO2 laser-assisted microvascular anastomosis.
(42) (42) (42) (42)
Anastomosis Time 95% 86% 96% 89%
15 19 18 25
min min min min
Irradiation Condition 5 28 33 0
sec 35mW 15 sec sec 30mW 15 sec
sec sec
Level Values (Inner Pressure Tolerance) Irradiation Power (mW) A, = 31
A2 = 38
A3 = 45
6 12 18 24
5.5 10 14.5 19
8 11 14
Values shown are seconds.
5
A4 == 53 45 6 7 .5 9
Downloaded by: University of British Columbia. Copyrighted material.
cumference, until the anastomosis was completed (Fig. 1). The basic factor in successful laser anastomosis is the same as in the manual approach, i.e., correct adaptation of the vascular intima. Also, of course, the stump must not be allowed to curl up inside the intima. An important point to remember in using the laser method is that, when stay sutures have been made in opposite directions, they must be applied slightly distant from the stump, so that adequate adaptation of the intima can be achieved. Another point is that during the period of hardening after tissue liquefaction by the laser beam, the stay sutures must be left in place. Otherwise, adaptation of the intima will be retarded and welding will take place, with a portion of the tunica externa and tunica media left extended; this, in turn, can easily cause an aneurysm or other defect. Similarly, failure can result, if adaptation of the vascular stump (especially the intima) is not obtained when the tension is adequate and the stay sutures have been taken in the opposite direction. Comparisons were carried out between the two methods by histologic examination, evaluation of patency rates and time required, and mechanical and tensile strength.
LASER-ASSISTED MICROANASTOMOSIS/KIYOSHIGE, TSUCHIDA, HAMASAKI, ET AL.
Downloaded by: University of British Columbia. Copyrighted material.
Table 3. Level Values (Tensile Strength) made at the M standard, a combination different from Mn can be established. However, if the combination of Irradiation Power (mW) Mn-1, corresponding to 1/M, is selected effectively Irradiation Time A 2 = 52 A, = 45 using orthogonal layout LMn-1, the same accuracy can 11 7.5 B, be obtained as when an experiment on Mn has been B 14 9 2 performed.) Optimum irradiation conditions were deValues shown are seconds. termined, and the time-course changes in inner-pressure tolerance of the anastomosed vessel under these conditions were compared with those of the manuallysutured vessel. Preliminary tests at 24 mW and 59 mW were conducted before the experiment. The four levels were established because anastomosis was impossible at and three days, six days, and nine days thereafter. A 24 mW even when the irradiation time was prolonged, strain gauge was used to measure tensile strength. The and at 59 mW because of large tissue lesions. An point at which part of the anastomosed vessel ruparterial segment of about 10 mm, including the anasto- tured and the strength dropped sharply was taken as mosed vessel, was removed immediately after anasto- the maximum tensile strength. mosis and one day, three days and seven days later. A It was thus determined that the optimal irradiabiopump was used to apply pressure to the anasto- tion conditions from the standpoint of tensile strength mosed vessel; the pressurized condition was meas- were an output at 45 mW and an irradiation time of 14 ured by pressure sensor; and the peak pressure imme- sec. The time-course changes in tensile strength under diately before part of the vessel ruptured and internal these conditions are shown in Figure 3 for both the pressure dropped sharply, was taken as the maximum laser and manual procedures. Similar time-course inner pressure tolerance. As a result, it was determined changes were exhibited by both groups, but the laser that the optimum irradiation conditions were a 52-mW group values were about half those of the manual irradiation output and 9 sec of irradiation time. The group. time-course changes in inner pressure tolerance under As a result, it was demonstrated that laser-assisted these conditions, with both the laser and manual pro- anastomosis had the following features, compared cedures, are shown in Figure 2. Similar time-course with manual suturing, and only three sutures are rechanges were exhibited by both procedures, and no quired (Table 4): 1. easier technique; 2. Less time resignificant differences were noted. quired for anastomosis; 3. less inflammatory reaction Tensile Strength. Based on the irradiation conditionsof tissue; 4. rapid tissue redegeneration; 5. no differfor inner pressure tolerance, irradiation output and ence in patency rate; and 6. no difference in internal irradiation time were each set at two-level values (Ta- pressure tolerance of the anastomosed vessel. The ble 3) from orthogonal layout L16 (215). An arterial major drawback of the laser procedure was that within segment of about 10 mm, including the anastomosed nine days after surgery, the tensile strength was about vessel, was removed immediately after anastomosis, half the value of that in the manual procedure.
v mmHg
6000 5000 4000
C o n t r o l (Manual method)
3000 2000 1000
500 400 300 200 100
C, C 2
immediately
I day
C3 3 day
C: 7 day
C,
C2
immediately
I day
C3 3 day
7 day postoperatively
Figure 2. The time-course changes in inner pressure tolerance. There is no significant difference between the laser procedure and the manual procedure.
227
JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 7, NUMBER 3
JULY 1991
200 Control
100
50 40 30 20
l0 L 3 days
6 days
9 days
postoperatively
Table 4.
Features of CO, Laser Procedure Easy to perform Less time-consuming Less tissue inflamation Easy wound healing Patency rate Inner pressure tolerance Tensile strength
Advantage
Disadvantage
CLINICAL APPLICATIONS The results of basic research on microvascular anastmosis using a CO2 laser, as described above, indicated that the laser procedure is in no way inferior to the manual procedure, if careful attention is paid to the tension of the anastomosed vessel. A CO2 laser was used in hand surgery for vascular anastomosis of 16 vessels (0.3 to 2.0 mm), done in six cases. Among these there were two cases of revascularization, three cases
Table 5. Case
Age
Sex
Revascularization 1 28 M 2 39 F Replantation 3 18 4 5
228
44 57
M M M
of replantation involving four digits, and one case of free-tissue transfer (Table 5). One of these cases involving replantation of a single digit was unsuccessful because the flow from the proximal artery was defective. CASE 1 (revascularization): A 28-year-old male suffered an injury when his right hand was caught in a drilling machine. The extensor tendon and the radial neurovascular bundle of the middle and ring fingers were torn and the index finger was severed incompletely, with about 3 mm of dorsal skin remaining over about 5 mm proximal to the PIP joint. Since the head of the proximal phalanx of the index finger was severed completely, osteosynthesis was performed without bone shortening, and thereafter, all tissues were restored. Three stay sutures were applied to the index finger radial indicis artery, with the PIP joint flexed at about 30 degrees, and a CO2 laser beam was irradiated between the sutures for anastomosis. However, when the microclamp was removed, part of the anastomosed
Clinical Applications
Injured Digit
Anstomosed Vessel
Right index Left ring
Rad. dig. artery Rad. dig. artery
1 yr 4 mo 4 mo
Right thumb Palm Right long Left index Left long
Rad. dig. artery, dorsal vein Superficial palm . arch Bilat • dig;. artery, two dorsal veins Rad. dig. artery, dorsal vein Rad. dig. artery, dorsal vein
1 yr 4 mo
Free-tissue transfer 6 52 M Right thumb (wrap-around flap)
1st metatarsal artery -> rad. artery (snuff box) Two branches of saph vein —* two branches of saph vein
Follow-up Period
9 mo 7 mo Failed 7 mo
Downloaded by: University of British Columbia. Copyrighted material.
immediately
Figure 3. The time-course changes of tensile strength. The values of the laser procedure are about 50 percent those of the manual procedure.
LASER-ASSISTED MICROANASTOMOSIS/KIYOSHIGE, TSUCHIDA, HAMASAKI, ET AL.
about 5 mm, one ulnar digital artery and one dorsal vein were anastomosed with CO2 laser. No tension of the anastomosed vessels was noted as vascular anastomosis was carried out in conjunction with bone shortening. We believe this to be the first case of replantation by CO2 laser-assisted vascular anastomosis, based on an exhaustive search of the literature (Fig. 5). CASE 6. (free tissue transfer case): A 51-year-old male underwent replantation surgery after all digits of the right hand had been amputated. He later underwent thumb reconstruction with an abdominal wall flap after his thumb began to show necrosis. A wraparound toe-to-thumb transfer, a method of compound free-tissue transfer from the big toe with nerves and nail included, was performed subsequently in order to restore sensation and functional shape. In the "snuffbox" region, the radial artery and the first metatarsal artery were anastomosed by CO2 laser, as well as two
Downloaded by: University of British Columbia. Copyrighted material.
vessel opened, and the radial indicis artery was dissected once again proximally and distally; the PIP joint wasflexedstill further; tension was reduced; and CO2 laser-assisted anastomosis was performed. An angiogram taken two months after surgery indicated that circulation was favorable with no constriction of the anastomosed vessel. One year and three months after surgery, the PIP joint range of motion was favorable with -20 degrees extension and 80 degrees flexion. No change in circulation due to finger motion was noted (Fig. 4). CASE 3. (replantation): An 18-year-old male suffered an injury when his right hand was caught in an electric power saw. All the tissues of the palm, except for the flexor digitorum profundus tendons, were torn, and the thumb was amputated at the distal phalangeal base. After CO2 laser-assisted anastomosis was performed on the superficial palmar arch, and after IPjoint arthrodesis with shortening of the thumb by
Figure 4. Case 1. a, Incomplete amputation of right indexfinger,b, Appearance at 16 months postoperatively. c, Postoperative angiogram at eight weeks showing a patent anastomosis.
V
b c Figure 5. Case 3. a, b, Complete amputation of right thumb, c, Complete survival of replanted thumb.
229
JOURNAL OF RECONSTRUCTIVE MICROSURGERY/VOLUME 7, NUMBER 3
JULY 1991
branches of the saphenous vein and two dorsal veins of the hand. Six months after surgery, sensation was restored favorably, and the reconstructed thumb could be used satisfactorily in functional terms. As far as we know, this is the first case in man in which a CO2 laser was used for free tissue transfer (Fig. 6).
DISCUSSION In our first case, there was much concern about tensile strength, but in the later cases, the tension of the anastomosis was reduced by such methods as bone shortening. In cases of free-tissue transfer (such as Case 6), since an appropriate tension can be established at the outset, we assume that problems of tensile strength can be adequately resolved in such clinical applications. In cases of multiple vascular anastomosis (e.g., Cases 4 and 5), the operation time can be reduced, compared with the conventional manual suturing procedure. The laser procedure is especially effective because, with only three stay sutures in the soft tissue of the veins, there is less damage to the vascular walls. In contrast to conventional manual suturing the new laser-assisted procedure enables anastomosis with only three stay sutures: it would be difficult to obtain favorable patency with so few sutures, using the conventional method. In view of its advantages, therefore, the new laser-assisted method can be expected to prove extremely useful in cases such as pediatric vascular anastomosis in which the vascular diameter is
230
narrow, in replantation of severed finger tips, or in minor tissue grafts.
SELECTED REFERENCES Freeman RH, Gordon jA: Microsurgical anastomosis using a CO2 laser: A preliminary report. Conference on Laser and Electro-Optics 60, 1982 Jain KK, Gorisch W: Repair of small blood vessels with the neodymium-YAG laser: Preliminary report. Surgery 85:684, 1979 Jain KK: Sutureless extra-intra-cranial anastomosis by laser. Lancet 816:, 1984 Kiyoshige Y: Microvascular anastomosis of rat femoral arteries with the CO2 laser: The effect of dynamic intensity of the anastomosed site against internal pressure. ) Jpn Soc Surg Hand 3:987, 1987 Kiyoshige Y: Microvascular anastomosis of rat femoral arteries with the CO2 laser: Chronological observation on tensile strength. I Ipn Soc Surg Hand 3:997, 1987 Oishi I: Microvascular anastomosis with a low-output carbon dioxide laser. I. Laser device, techniques, and conditions of anastomosis. I Ipn Orthop Assoc 60:801, 1986 Oishi J; Microvascular anastomosis with a low-output carbon dioxide laser. II. Histopathological features. J Ipn Orthop Assoc 60:813, 1986 Okada M, Simizu K, Ikuta H: An alternative method of vascular anastomosis by laser: Experimental and clinical study. Laser Surg Med 7:240, 1987 Serure A, Withers EH, Thomson S, et al.: Comparison of carbon dioxide laser-assisted microvascular anastomosis and conventional microvascular sutured anastomosis. Surg Forum 34:634, 1983 Takayanagi M, Watanabe Y, Kiyoshige Y, et al.: Experimental study of micro-vascular anastomosis using CO2 laser. I Ipn Soc Surg Hand 2:693, 1985 Vale BH, Frenkel AMS, Trenka-Benthin S, et ah. Microsurgical anastomosis of rat carotid arteries with CO2 laser. Plast Reconstr Surg 177:759, 1986
Downloaded by: University of British Columbia. Copyrighted material.
Figure 6. Case 6. a, Amputation of all of right digits, b, Appearance of the reconstructed thumb by pedicle groin flap. The fingers suvived. c, Free vascularized wraparound flap from right big toe. d, Complete survival of free flap.
