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Vascular anatomic variations in second toe transfers
Vascular Anatomic Variations in Second Toe Transfers Yu-Dong Gu, MD, Gao-Meng Zhang, MD, De-Song Chen, MD, Xiao-Min Cheng, MD, Jian-Guang Xu, MD, Huan Wang, MD, Shanghai, People’s Republic of China To devise a new classification of vascular variations in second toe transfer we analyzed the anatomic details of the first dorsal metatarsal artery in 304 cases of second toe transplantation and the venous structure in 200 cases. According to location, the arterial vascularity was classified as superficial (18% of cases), intramuscular (54%), inframuscular (23%), and absent (5%). According to diameter, it was classified into large (16%), medium (64%), and small (20%). Based on branching pattern, the artery was classified into ramifying type (88%), main trunk (4%), and fine branch type (8%). The venous drainage of the second toe was categorized as greater saphenous vein main trunk type, greater saphenous vein fine branch type, dorsal digital vein main trunk type, and dorsal digital vein fine branch type. Variations of the first dorsal metatarsal artery are common. Classification should be done according to its location, diameter, and branching pattern at the toe web. Regardless of location, big vessels entering the second toe are the most important attribute for successful outcome. (J Hand Surg 2000;25A: 277–281. Copyright © 2000 by the American Society for Surgery of the Hand.) Key words: Toe transfer, blood vessel.
Toe to hand transfer has become a widely accepted surgical procedure for reconstruction of the thumb or for finger loss. There are numerous reports of the results, technical modifications, and relevant anatomic studies of toe transfer.1–3 There are, however, few reports of vascularity in toe transplantation. The accepted classification is Gilbert’s classification scheme.4 We have performed more than 400 second toe transfers and have reported the detailed surgical techniques and the factors influencing transplant survival.5– 8 We have found that Gilbert’s classification of vascularity does not cover the very complicated From the Department of Hand Surgery, Huashan Hospital, Shanghai Medical University, Shanghai, People’s Republic of China. Received for publication February 17, 1999; accepted in revised form November 11, 1999. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Yu-Dong Gu, MD, Department of Hand Surgery, Huashan Hospital, Shanghai Medical University, 12 Wulumuqi Zhong Rd, Shanghai 200040, People’s Republic of China. Copyright © 2000 by the American Society for Surgery of the Hand 0363-5023/00/25A02-0017$3.00/0
conditions encountered in toe transplantation. Therefore, based on our experience and the data gathered from a prospective study of the cases in our clinical practice, we devised and present a new clinical classification scheme of vascularity in second toe transplantation.
Materials and Methods Clinical Data Between February 1966 and February 1994 we performed 400 second toe transplantation procedures. The transplants survived in 386 cases and failed in 14 cases, with an overall survival rate of 97%. Intraoperative findings of the anatomy of the vascularity at the donor site (the foot) were recorded in detail in 304 cases. Of these 304 cases, 232 were male and 72 were female. The age of the patients ranged from 5 to 58 years (average, 34 years). The thumb and finger defects were attributed to trauma in 300 cases and congenital abnormalities in 4 cases. There were 220 cases involving the thumb, 32 involving the index finger, 28 involving the index and The Journal of Hand Surgery 277
278 Gu et al / Vascularity in Toe Transplantation
middle finger, 17 involving the middle finger, 4 involving the ring finger, and 3 involving the little finger.
Measurement and Observation The greater saphenous vein, the dorsal pedal vein, and the dorsal digital vein were dissected to mobilize the venous drainage structure of the second toe. The dorsalis pedis artery, the first dorsal metatarsal artery (FDMA), and the branches of FDMA at the first toe web were then dissected. The outside diameters of the vessels were measured using a sliding gage (Shanghai Weighing Apparatus Manufacturer, Shanghai, People’s Republic of China) without removal of the adventitia. The accuracy of the sliding gage was 0.01 mm. The relationship of the first dorsal metatarsal artery to the dorsal interosseous muscle was then observed.
Criteria for Classification Arterial system. The relationship of the initial part of the proximal half of the first dorsal metatarsal artery to the interosseous muscle (Fig. 1) was defined as superficial (the FDMA lies superficial to the surface of the interosseous muscle), intramuscular (the FDMA travels within the interosseous muscle), inframuscular (the FDMA runs in the deeper layer of the interosseous muscle), or absent. The diameter detected at the midpoint of the first dorsal metatarsal artery was defined as large (the diameter of the artery is ⬎1.5 mm), medium (the diameter of the artery ranges from 1.0 to 1.5 mm), or small (the diameter of the artery is ⬍1.0 mm). The diameter of the branches from the first dorsal metatarsal artery to the second toe (Fig. 2) was classified as ramifying (the diameter of the branch to
Figure 2. The branching pattern of the first dorsal metatarsal artery at the toe web.
the second toe ranges from 0.5 to 0.8 mm; the FDMA at the first toe web bifurcates to the second toe and to the hallux with branches of similar caliber), main trunk (the diameter of the branch to the second toe is ⬎0.8 mm; the FDMA forms a large branch to the second toe and a fine branch to the hallux at the toe web), or fine branch (the diameter of the branch to the second toe is ⬍0.5 mm; the FDMA forms a fine branch to the second toe and a large branch to the hallux). Venous system. The venous pattern was classified according to the relationship of the dorsal digital vein to the greater saphenous vein and the diameter of the dorsal digital vein.
Analysis The cases that failed with different types of vascularity were analyzed and the failure rate was calculated. The relationship between the failure rate and vascular type was analyzed.
Results
Figure 1. Location of the first dorsal metatarsal artery.
Anatomic data regarding the first dorsal metatarsal artery were obtained for analysis in 304 of the 400 cases of toe transplantation. The FDMA was considered superficial in 58 cases (18%), intramuscular in 172 (54%), inframuscular in 74 (23%), and absent in 16 (5%). The diameter of the FDMA was large in 50 cases (16%), medium in 193 (63%), and small in 61 (20%). The branching pattern of the FDMA at the toe web was ramifying in 266 cases (88%), the main trunk in 11 cases (4%), and the fine branch in 27 cases (8%). The correlation of the criteria of the FDMA is presented in Table 1.
The Journal of Hand Surgery / Vol. 25A No. 2 March 2000 279
Table 1. Correlation of the Criteria of the First Dorsal Metatarsal Artery Large (n ⫽ 50)
Medium (n ⫽ 193)
Small (n ⫽ 61)
Ramifying
Main Trunk
Fine Branch
Ramifying
Main Trunk
Fine Branch
Ramifying
Main Trunk
Fine Branch
Total
4 33 3 40
5 3 0 8
0 0 2 2
32 101 45 178
1 1 1 3
1 6 5 12
12 24 12 48
0 0 0 0
3 4 6 13
58 172 74 304
Location Superficial Intramuscular Inframuscular Total
The relationship of vascularity and survival of the second toe transfer is demonstrated in Tables 2, 3, and 4. Analysis of the data presented in Table 2 revealed that the failure rate in the small FDMA cases (10%) was statistically higher than the failure rates of the large and medium-sized FDMAs (p ⬍ .05; t-test). Table 3 shows that there was no significant difference between the failure rate of the superficial and the inframuscular FDMAs (p ⬎ .05; t-test). The failure rate of the intramuscular FDMAs was much lower than that of the superficial and inframuscular FDMAs. The difference was statistically significant (p ⬍ .05; t-test). These results indicate that the survival of the transfer was related to the diameter of the vessel, not its position. Statistical analysis of the relationship between the failure rate and the branching pattern of the FDMA at the toe web showed that the failure rate was as high as 26% when the diameter of the branch from the first dorsal metatarsal artery to the second toe was very small (fine branch). There were no failed cases in the main trunk FDMAs and 3% failed cases in the ramifying FDMAs. The failure rate of the fine branch FDMAs was dramatically higher than that of the main trunk and ramifying FDMAs (p ⬍ .001; t-test),
Table 2. Relationship Between the Size of the First Dorsal Metatarsal Artery and Failure Rate Large (n ⫽ 50) Medium (n ⫽ 193) Small (n ⫽ 61) Total (n ⫽ 304 ⫹ 96*)
No. of Failed Cases
Failure Rate
2 6 6 14
4% 4% 10% 4%†
* Survived cases without detailed anatomic data for analysis. † Failure rate of 400 cases.
indicating that the survival of the second toe transfer was closely related to the branching pattern of the FDMA at the toe web. The procedures were performed by 3 surgeons who had a similar experience level and performed the second toe transfer in a similar manner. Therefore, the experience level of the surgeon did not affect the outcome. The anatomy of the venous system was recorded in detail in 200 cases. The venous return of the second toe can be classified into 1 of 4 anatomic types: greater saphenous main trunk, greater saphenous vein fine branch, dorsal digital vein main trunk, and dorsal digital vein fine branch. One hundred eighty-seven cases (94%) were classified as having a greater saphenous vein main trunk, in which 1 or 2 relatively large dorsal digital veins (diameter, ⬎1.5 mm) converge at the dorsum of the second toe and then drain to the greater saphenous venous arch. Three cases (2%) were identified as having a greater saphenous vein fine branch, in which only 1 or 2 small dorsal digital veins (diameter, ⬍0.5 mm) from the dorsum of the second toe drain into the greater saphenous vein. The toe is drained mainly by the venae comitantes and the tarsal venous reflow. Six cases (3%) had a dorsal digital vein main trunk, in which the venous arch of the greater saphenous is absent. One to 2 dorsal digital veins (diameter, 1.5–2.0 mm) traverse the dorsum of the foot and drain into the greater saphenous vein at the level of ankle (diameter at the entering site, 2–3 mm). The remaining 4 cases (2%) had a dorsal digital vein fine branch, in which the venous arch of the greater saphenous vein is absent. Several minute dorsal digital veins form a venous network at the dorsum of the foot and drain into the saphenous vein at the ankle.
280 Gu et al / Vascularity in Toe Transplantation
Table 3. Relationship Between the Location of the First Dorsal Metatarsal Artery and Failure Rate No. of Failed Cases Failure Rate Superficial (n ⫽ 58) Intramuscular (n ⫽ 172) Inframuscular (n ⫽ 74) Total (n ⫽ 304 ⫹ 96*)
3 6 5 14
5% 2% 7% 4%†
* Survived cases without detailed anatomic data for analysis. † Failure rate of 400 cases.
Discussion Clinical Significance of Specific Anatomic Attributes of the First Dorsal Metatarsal Artery Although toe transplantation can be directly based on the digital artery or the plantar metatarsal artery, the dorsalis pedis– dorsal metatarsal system, the socalled “first set of blood supply system,” is generally used. In this system the dissection and isolation of the FDMA is crucial to the success of toe transplantation. The identification of variations of the FDMA is therefore the topic in which most anatomists and surgeons are interested.9 –12 Gilbert’s classification is the widely accepted grouping system: type I, superficial; type II, deep; and type III, fine branch or absent. This kind of classification is simple, but it possesses several disadvantages. The first disadvantage is that the demarcation among different types is vague. The FDMA is categorized as type I when it is located in the superficial layer of the interosseous muscle. If FDMA lies in the deeper layer of the interosseous muscle, it is classified as type II. The precise demarcation of the superficial and deep layers in the interosseous muscle is not clearly demonstrated in Gilbert’s classification. In addition, there is no difference between the failure rate of the most superficial type and the deepest type (see Table 3). Therefore, the location of the FDMA is not a determining factor regarding the success of the procedure. Second, the location and size of the vessel are confused. The diameter of the FDMA can be large, medium, or small. The different sizes of the vessel lead to different prognoses. Three types of vascular sizes can be met in different types of vascular position. In the superficial and inframuscular types, the vessel could be large, medium, or small. The risk of vascular crisis is highest in a case in which the FDMA is small and is deep in the interosseous mus-
cle. Manipulation in this type is very difficult and often causes spasm of the vessel. Similarly, spasm often occurs in small vessels of the superficial type. It is therefore very important to clarify the relationship between the location and size of the FDMA. Another disadvantage of Gilbert’s classification is that the crucial anatomy is not clearly stated. The key to the anatomy of the FDMA is the type of the vessel at the toe web. Whatever the location or size of the vessel, meticulous dissection and consummate anastomosis can lead to successful toe transplantation as long as the branching pattern of the FDMA at the toe web is of the ramifying or main trunk type. In cases in which the FDMA enters the second toe in a fine branch, the second set of blood supply1 should be applied or toe transplantation delayed to ensure the success of the procedure. To provide the double arterial blood supply the second dorsal metatarsal artery or the plantar perforating branch with the plantar common metatarsal artery was also isolated, or the distal segment of the second dorsal metatarsal artery was anastomosed to the proximal segment of the plantar perforating branch to ensure sufficient perfusion of the transferred toe. Consequently, classification of the branching pattern of the FDMA at the toe web should be considered a priority. We suggest that the clinical classification of FDMA include three components: location (I, superficial; II, intramuscular; III, inframuscular; and IV, absent), size (L, diameter ⬎ 1.5 mm; M, diameter 1.0 –1.5 mm; and S, diameter ⬍ 1.0 mm), and branching pattern (R, ramifying type; T, main trunk type; and F, fine branch type). The most common R type is expressed as II and the type involving the M F greatest risk is expressed as III . S
Table 4. Relationship Between Branching Pattern at Toe Web and Failure Rate Main trunk (n ⫽ 11) Ramifying (n ⫽ 266) Fine branch (n ⫽ 27) Total (n ⫽ 304 ⫹ 96*)
No. of Failed Cases
Failure Rate
0 7 7 14
0 3% 26% 4%†
* Survived cases without detailed anatomic data for analysis. † Failure rate of 400 cases.
The Journal of Hand Surgery / Vol. 25A No. 2 March 2000 281
Management for Various Vascular Patterns in Toe Transplantation If the following types of vascularity are met before toe transplantation, the procedure is performed in a routine manner: T R T R T R T R T R I , I , I , I , II , II , II , II , III , III , or L L M M L L M M L L T III . If the following types of vascularity are met M before toe transplantation, application of the second set of blood supply is strongly recommended: F F R T F F F F R T I , I , I , I , II , II , II , II , III , III , L M S S L M S S L M R T F F F R III , III , III , I , II , or III . If there is no M S S S S S available second set of blood supply system and uncorrectable circulation crisis occurs during surgery, toe transplantation should be delayed. In short, regardless of location, the size of the vessels entering the second toe is the most important attribute for successful outcome.
Venous Types in Toe Transplantation In toe transplantation there are relatively fewer venous problems. Only one case failed because of venous crisis in our series of 400 toe transfers. Variations in the venous system are not common. The greater saphenous vein main trunk type constitutes 94% of cases and the dorsal digital vein main trunk type constitutes 3%. The size of the veins in these
types is relatively large. Therefore, the classification of the venous system is simple.
References 1. Gu Y, Zhang G, Chen D, Yan J, Cheng X. Free toe transfer for thumb and finger reconstruction in 300 cases. Plast Reconstr Surg 1993;91:693– 699. 2. Gu Y, Zhang G, Chen D, Yan J, Chen X. Toe-to-hand transfer: an analysis of 14 failed cases. J Hand Surg 1993; 18A:823– 827. 3. Gu Y-D, Wu M-M, Zheng Y-L, Yang D-Y, Li H-R. Vascular variations and their treatment in toe transplantation. J Reconstr Microsurg 1985;1:227–230. 4. Masquelet AC, Gilbert A. Transfers from the lower limb. In: An atlas of flaps in limb reconstruction. London: Martin Dunitz, 1995:196 –199. 5. Gu YD, Wu MM, Zhen YL, et al. The vascular variations in toe transplantation and its management. Chin J Hand Surg 1985;23:21–24. 6. Gu YD, Zhang LY, Zhang L, et al. Vascular pathology in toe transplantation and its clinical significance. Chin J Microsurg 1986;9:86 – 87. 7. Gu YD, Wu MM, Li HR, et al. Circulatory crisis in toe transplantation and its management. Chin J Hand Surg 1986;24:257–260. 8. Gu YD, Chen DS, Zhang GM, et al. Toe transfer for reconstruction of thumb and fingers: a report of 400 cases. Chin J Hand Surg 1995;11:195–199. 9. Xu ED. Surgical anatomy of the vessels of the foot. Chin J Orthop Surg 1981;1:240 –242. 10. Wu JB. Distribution and anastomosis of the first dorsal metatarsal artery. J Clin Appl Anat 1984;2:6 –10. 11. Ling T. The clinical significance of vessels on dorsum of the foot to toe and flap transplantation. Chin J Surg 1981;19:297–300. 12. Gilbert A. Composite tissue transfer from the foot: anatomic basis and surgical technique. In: Symposium on microsurgery. St Louis; CV Mosby, 1976:230 –236.
Toe to hand transfer has become a widely accepted surgical procedure for reconstruction of the thumb or for finger loss. There are numerous reports of the results, technical modifications, and relevant anatomic studies of toe transfer.1–3 There are, however, few reports of vascularity in toe transplantation. The accepted classification is Gilbert’s classification scheme.4 We have performed more than 400 second toe transfers and have reported the detailed surgical techniques and the factors influencing transplant survival.5– 8 We have found that Gilbert’s classification of vascularity does not cover the very complicated From the Department of Hand Surgery, Huashan Hospital, Shanghai Medical University, Shanghai, People’s Republic of China. Received for publication February 17, 1999; accepted in revised form November 11, 1999. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Yu-Dong Gu, MD, Department of Hand Surgery, Huashan Hospital, Shanghai Medical University, 12 Wulumuqi Zhong Rd, Shanghai 200040, People’s Republic of China. Copyright © 2000 by the American Society for Surgery of the Hand 0363-5023/00/25A02-0017$3.00/0
conditions encountered in toe transplantation. Therefore, based on our experience and the data gathered from a prospective study of the cases in our clinical practice, we devised and present a new clinical classification scheme of vascularity in second toe transplantation.
Materials and Methods Clinical Data Between February 1966 and February 1994 we performed 400 second toe transplantation procedures. The transplants survived in 386 cases and failed in 14 cases, with an overall survival rate of 97%. Intraoperative findings of the anatomy of the vascularity at the donor site (the foot) were recorded in detail in 304 cases. Of these 304 cases, 232 were male and 72 were female. The age of the patients ranged from 5 to 58 years (average, 34 years). The thumb and finger defects were attributed to trauma in 300 cases and congenital abnormalities in 4 cases. There were 220 cases involving the thumb, 32 involving the index finger, 28 involving the index and The Journal of Hand Surgery 277
278 Gu et al / Vascularity in Toe Transplantation
middle finger, 17 involving the middle finger, 4 involving the ring finger, and 3 involving the little finger.
Measurement and Observation The greater saphenous vein, the dorsal pedal vein, and the dorsal digital vein were dissected to mobilize the venous drainage structure of the second toe. The dorsalis pedis artery, the first dorsal metatarsal artery (FDMA), and the branches of FDMA at the first toe web were then dissected. The outside diameters of the vessels were measured using a sliding gage (Shanghai Weighing Apparatus Manufacturer, Shanghai, People’s Republic of China) without removal of the adventitia. The accuracy of the sliding gage was 0.01 mm. The relationship of the first dorsal metatarsal artery to the dorsal interosseous muscle was then observed.
Criteria for Classification Arterial system. The relationship of the initial part of the proximal half of the first dorsal metatarsal artery to the interosseous muscle (Fig. 1) was defined as superficial (the FDMA lies superficial to the surface of the interosseous muscle), intramuscular (the FDMA travels within the interosseous muscle), inframuscular (the FDMA runs in the deeper layer of the interosseous muscle), or absent. The diameter detected at the midpoint of the first dorsal metatarsal artery was defined as large (the diameter of the artery is ⬎1.5 mm), medium (the diameter of the artery ranges from 1.0 to 1.5 mm), or small (the diameter of the artery is ⬍1.0 mm). The diameter of the branches from the first dorsal metatarsal artery to the second toe (Fig. 2) was classified as ramifying (the diameter of the branch to
Figure 2. The branching pattern of the first dorsal metatarsal artery at the toe web.
the second toe ranges from 0.5 to 0.8 mm; the FDMA at the first toe web bifurcates to the second toe and to the hallux with branches of similar caliber), main trunk (the diameter of the branch to the second toe is ⬎0.8 mm; the FDMA forms a large branch to the second toe and a fine branch to the hallux at the toe web), or fine branch (the diameter of the branch to the second toe is ⬍0.5 mm; the FDMA forms a fine branch to the second toe and a large branch to the hallux). Venous system. The venous pattern was classified according to the relationship of the dorsal digital vein to the greater saphenous vein and the diameter of the dorsal digital vein.
Analysis The cases that failed with different types of vascularity were analyzed and the failure rate was calculated. The relationship between the failure rate and vascular type was analyzed.
Results
Figure 1. Location of the first dorsal metatarsal artery.
Anatomic data regarding the first dorsal metatarsal artery were obtained for analysis in 304 of the 400 cases of toe transplantation. The FDMA was considered superficial in 58 cases (18%), intramuscular in 172 (54%), inframuscular in 74 (23%), and absent in 16 (5%). The diameter of the FDMA was large in 50 cases (16%), medium in 193 (63%), and small in 61 (20%). The branching pattern of the FDMA at the toe web was ramifying in 266 cases (88%), the main trunk in 11 cases (4%), and the fine branch in 27 cases (8%). The correlation of the criteria of the FDMA is presented in Table 1.
The Journal of Hand Surgery / Vol. 25A No. 2 March 2000 279
Table 1. Correlation of the Criteria of the First Dorsal Metatarsal Artery Large (n ⫽ 50)
Medium (n ⫽ 193)
Small (n ⫽ 61)
Ramifying
Main Trunk
Fine Branch
Ramifying
Main Trunk
Fine Branch
Ramifying
Main Trunk
Fine Branch
Total
4 33 3 40
5 3 0 8
0 0 2 2
32 101 45 178
1 1 1 3
1 6 5 12
12 24 12 48
0 0 0 0
3 4 6 13
58 172 74 304
Location Superficial Intramuscular Inframuscular Total
The relationship of vascularity and survival of the second toe transfer is demonstrated in Tables 2, 3, and 4. Analysis of the data presented in Table 2 revealed that the failure rate in the small FDMA cases (10%) was statistically higher than the failure rates of the large and medium-sized FDMAs (p ⬍ .05; t-test). Table 3 shows that there was no significant difference between the failure rate of the superficial and the inframuscular FDMAs (p ⬎ .05; t-test). The failure rate of the intramuscular FDMAs was much lower than that of the superficial and inframuscular FDMAs. The difference was statistically significant (p ⬍ .05; t-test). These results indicate that the survival of the transfer was related to the diameter of the vessel, not its position. Statistical analysis of the relationship between the failure rate and the branching pattern of the FDMA at the toe web showed that the failure rate was as high as 26% when the diameter of the branch from the first dorsal metatarsal artery to the second toe was very small (fine branch). There were no failed cases in the main trunk FDMAs and 3% failed cases in the ramifying FDMAs. The failure rate of the fine branch FDMAs was dramatically higher than that of the main trunk and ramifying FDMAs (p ⬍ .001; t-test),
Table 2. Relationship Between the Size of the First Dorsal Metatarsal Artery and Failure Rate Large (n ⫽ 50) Medium (n ⫽ 193) Small (n ⫽ 61) Total (n ⫽ 304 ⫹ 96*)
No. of Failed Cases
Failure Rate
2 6 6 14
4% 4% 10% 4%†
* Survived cases without detailed anatomic data for analysis. † Failure rate of 400 cases.
indicating that the survival of the second toe transfer was closely related to the branching pattern of the FDMA at the toe web. The procedures were performed by 3 surgeons who had a similar experience level and performed the second toe transfer in a similar manner. Therefore, the experience level of the surgeon did not affect the outcome. The anatomy of the venous system was recorded in detail in 200 cases. The venous return of the second toe can be classified into 1 of 4 anatomic types: greater saphenous main trunk, greater saphenous vein fine branch, dorsal digital vein main trunk, and dorsal digital vein fine branch. One hundred eighty-seven cases (94%) were classified as having a greater saphenous vein main trunk, in which 1 or 2 relatively large dorsal digital veins (diameter, ⬎1.5 mm) converge at the dorsum of the second toe and then drain to the greater saphenous venous arch. Three cases (2%) were identified as having a greater saphenous vein fine branch, in which only 1 or 2 small dorsal digital veins (diameter, ⬍0.5 mm) from the dorsum of the second toe drain into the greater saphenous vein. The toe is drained mainly by the venae comitantes and the tarsal venous reflow. Six cases (3%) had a dorsal digital vein main trunk, in which the venous arch of the greater saphenous is absent. One to 2 dorsal digital veins (diameter, 1.5–2.0 mm) traverse the dorsum of the foot and drain into the greater saphenous vein at the level of ankle (diameter at the entering site, 2–3 mm). The remaining 4 cases (2%) had a dorsal digital vein fine branch, in which the venous arch of the greater saphenous vein is absent. Several minute dorsal digital veins form a venous network at the dorsum of the foot and drain into the saphenous vein at the ankle.
280 Gu et al / Vascularity in Toe Transplantation
Table 3. Relationship Between the Location of the First Dorsal Metatarsal Artery and Failure Rate No. of Failed Cases Failure Rate Superficial (n ⫽ 58) Intramuscular (n ⫽ 172) Inframuscular (n ⫽ 74) Total (n ⫽ 304 ⫹ 96*)
3 6 5 14
5% 2% 7% 4%†
* Survived cases without detailed anatomic data for analysis. † Failure rate of 400 cases.
Discussion Clinical Significance of Specific Anatomic Attributes of the First Dorsal Metatarsal Artery Although toe transplantation can be directly based on the digital artery or the plantar metatarsal artery, the dorsalis pedis– dorsal metatarsal system, the socalled “first set of blood supply system,” is generally used. In this system the dissection and isolation of the FDMA is crucial to the success of toe transplantation. The identification of variations of the FDMA is therefore the topic in which most anatomists and surgeons are interested.9 –12 Gilbert’s classification is the widely accepted grouping system: type I, superficial; type II, deep; and type III, fine branch or absent. This kind of classification is simple, but it possesses several disadvantages. The first disadvantage is that the demarcation among different types is vague. The FDMA is categorized as type I when it is located in the superficial layer of the interosseous muscle. If FDMA lies in the deeper layer of the interosseous muscle, it is classified as type II. The precise demarcation of the superficial and deep layers in the interosseous muscle is not clearly demonstrated in Gilbert’s classification. In addition, there is no difference between the failure rate of the most superficial type and the deepest type (see Table 3). Therefore, the location of the FDMA is not a determining factor regarding the success of the procedure. Second, the location and size of the vessel are confused. The diameter of the FDMA can be large, medium, or small. The different sizes of the vessel lead to different prognoses. Three types of vascular sizes can be met in different types of vascular position. In the superficial and inframuscular types, the vessel could be large, medium, or small. The risk of vascular crisis is highest in a case in which the FDMA is small and is deep in the interosseous mus-
cle. Manipulation in this type is very difficult and often causes spasm of the vessel. Similarly, spasm often occurs in small vessels of the superficial type. It is therefore very important to clarify the relationship between the location and size of the FDMA. Another disadvantage of Gilbert’s classification is that the crucial anatomy is not clearly stated. The key to the anatomy of the FDMA is the type of the vessel at the toe web. Whatever the location or size of the vessel, meticulous dissection and consummate anastomosis can lead to successful toe transplantation as long as the branching pattern of the FDMA at the toe web is of the ramifying or main trunk type. In cases in which the FDMA enters the second toe in a fine branch, the second set of blood supply1 should be applied or toe transplantation delayed to ensure the success of the procedure. To provide the double arterial blood supply the second dorsal metatarsal artery or the plantar perforating branch with the plantar common metatarsal artery was also isolated, or the distal segment of the second dorsal metatarsal artery was anastomosed to the proximal segment of the plantar perforating branch to ensure sufficient perfusion of the transferred toe. Consequently, classification of the branching pattern of the FDMA at the toe web should be considered a priority. We suggest that the clinical classification of FDMA include three components: location (I, superficial; II, intramuscular; III, inframuscular; and IV, absent), size (L, diameter ⬎ 1.5 mm; M, diameter 1.0 –1.5 mm; and S, diameter ⬍ 1.0 mm), and branching pattern (R, ramifying type; T, main trunk type; and F, fine branch type). The most common R type is expressed as II and the type involving the M F greatest risk is expressed as III . S
Table 4. Relationship Between Branching Pattern at Toe Web and Failure Rate Main trunk (n ⫽ 11) Ramifying (n ⫽ 266) Fine branch (n ⫽ 27) Total (n ⫽ 304 ⫹ 96*)
No. of Failed Cases
Failure Rate
0 7 7 14
0 3% 26% 4%†
* Survived cases without detailed anatomic data for analysis. † Failure rate of 400 cases.
The Journal of Hand Surgery / Vol. 25A No. 2 March 2000 281
Management for Various Vascular Patterns in Toe Transplantation If the following types of vascularity are met before toe transplantation, the procedure is performed in a routine manner: T R T R T R T R T R I , I , I , I , II , II , II , II , III , III , or L L M M L L M M L L T III . If the following types of vascularity are met M before toe transplantation, application of the second set of blood supply is strongly recommended: F F R T F F F F R T I , I , I , I , II , II , II , II , III , III , L M S S L M S S L M R T F F F R III , III , III , I , II , or III . If there is no M S S S S S available second set of blood supply system and uncorrectable circulation crisis occurs during surgery, toe transplantation should be delayed. In short, regardless of location, the size of the vessels entering the second toe is the most important attribute for successful outcome.
Venous Types in Toe Transplantation In toe transplantation there are relatively fewer venous problems. Only one case failed because of venous crisis in our series of 400 toe transfers. Variations in the venous system are not common. The greater saphenous vein main trunk type constitutes 94% of cases and the dorsal digital vein main trunk type constitutes 3%. The size of the veins in these
types is relatively large. Therefore, the classification of the venous system is simple.
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