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MINISTRY OF EDUCATION AND TRAINING MINISTRY OF DEFENCE 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES VIET TAN NGUYEN ANATOMICAL RESEARCH OF ARTERIAL SUPPLY TO THE GREAT AND SECOND TOES[.]

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VIET TAN NGUYEN

ANATOMICAL RESEARCH OF ARTERIAL SUPPLY TO THE GREAT AND SECOND TOES BY COMPUTED TOMOGRAPHY ANGIOGRAPHY AND EVALUATING THE RESULTS OF THE TOE-TO-THUMB TRANSFER

THE THESIS WAS DONE IN: 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES

Supervisor:

1 Assoc Prof – Ph.D Van Doan Le

2 Prof – Ph.D Khanh Lam

Day Month Year

The thesis can be found at:

1 National Library of Vietnam

2 Library of 108 Institute of Clinical Medical and

Pharmaceutical Sciences

INTRODUCTION

The thumb is the most important digit and constitutes approximately 50 % of the hand function Therefore, when the thumb is lost, the indication of thumb reconstruction is always requested In thumb reconstruction, toe-to-thumb transfer is a gold standard procedure compared to other traditional methods like phalangization, thumb metacarpal lengthening, and osteoplastic reconstruction, pollicization

The common types of toe-to-thumb transfers are the second toe, great toe, trimmed great toe, and the great toe wrap-around transfers In general, the basic issues related to it have been comprehensively reported, for example: surgical indications, the surgical technique of toe harvesting and toe transplantation to the thumb, and post-operatively monitoring and treatment However, according to a study by Lin P.Y et al (2011) consisting of evidence-based medicine, there were still several different opinions and comments about toe flap selection, donor foot morbidity, and functional, aesthetic outcomes amongst different methods of the toe-to-thumb transfers

In the toe-to-thumb transfer surgery, the dorsalis pedis artery (DPA) and the first dorsal metatarsal artery (FDMA) are preferred for use

as the arterial pedicle of the toe flaps thanks to the following advantages: these two arteries are superficial and easy to dissect, and the vascular pedicles are long with large diameters However, many studies have shown that DPA and especially FDMA have great anatomical variability

In Vietnam, although the first free toe-to-thumb transfer surgery was performed in 1988 by Huy Phan Nguyen, until now it has not been widely applied, the number of reports is limited with small sample sizes, and the conclusions related to the results of the transferred toe, the donor

foot morbidity have not been described in detail Regarding to the anatomical study of the arteries supplying blood to the great and second toe flaps, there were only two studies of Vietnam Military Medical University in 2017 and 2022 based on traditional dissection on Vietnamese cadavers preserved in formalin

As a response to the above, we performed research entitled

“Anatomical research of arterial supply to the great and second toes

by computed tomography angiography and evaluating the results of the toe-to-thumb transfer surgery” with two following targets:

1 Describing the anatomical characteristics of the arteries supplying blood to the great and second toe flaps in Vietnamese adults using computed tomography angiography

2 Evaluating the results of the toe-to-thumb transfer surgery and the donor foot morbidity

ARRANGEMENT OF THE THESIS

The thesis consists of 116 pages (excluding references and appendices), with the following main parts:

- Introduction: 2 pages

- Chapter 1 Literature Overview: 31 pages

- Chapter 2 Subjects and methods: 22 pages

- Chapter 3 Results: 33 pages

- Chapter 4 Discussion: 26 pages Conclusion: 2 pages

- The thesis has 35 tables, 45 figures

- References: 149 documents (15 Vietnamese, 134 foreign languages)

- 06 articles related to the topic have been published

Chapter 1 LITERATURE OVERVIEW

1 1 Thumb amputation and reconstruction methods

1.1.1 Classification of thumb amputation

Campbell – Reid D.A (1960) classified thumb defects into four groups: Group I: Amputation distal to the metacarpophalangeal (MCP) joint, leaving an adequate stump of proximal phalanx or of proximal and distal phalanges Group II: Amputation distal to or through the MCP joint leaving a stump of inadequate length Group III: Amputation through the metacarpal leaving some intrinsic musculature Group IV: Amputation at the carpometacarpal (CMC) joint

1.1.2 Thumb reconstruction via non-microsurgical techniques

- First web deepening method

- Metacarpal lengthening

- Osteoplastic reconstruction

- Pollicization

- The pedicled toe-to-thumb transfer surgery

1.1.3 Thumb reconstruction by free toe-to-thumb transfer surgery

- Great toe transfer

- Trimmed great toe transfer

- Great toe wrap-around transfer

- Second toe transfer

1.2 Anatomical study of arteries supplying to the great and second toe flaps

1.2.1 Overview of the arterial anatomy of the foot

According to Trinh Van Minh, the foot is supplied blood by three main arterial sources: the dorsalis pedis artery, the lateral plantar artery,

and the medial plantar artery

1.2.2 Anatomical study of the arterial supply of the great and second toe flaps in the world

1.2.2.1 Anatomical variations of the dorsalis pedis artery

* Frequency of absent DPA This rate is 12% in Huber J.F.’s study (1941); 4/70 (5,7%) in Leung P.C.’s (1983); 6,7% in Yamada T.’s (1993); 20% in Martínez Villén G.’s (2002); 9,5% in Rajeshwari M.S.’s (2013); 2% in George A (2020)

* The course of DPA in the ankle According to Huber J.F., most of DPAs travel in the middle third of the ankle in the direction from the mid-point between two malleoli to the proximal end of the first intermetatarsal space

* Caliber In the study of Man D (1980), the average external diameter of DPA at the upper limit of the extensor retinaculum is 2,79 mm In the study

of Yamada T (1993) with the traditional method of cadaver dissection, the mean diameter of DPA at 3cm distal to the ankle is 2,07 ± 0,77mm

1.2.2.2 First dorsal metatarsal artery and its variations

* Variations in the origin of the first dorsal metatarsal artery According to Zhu J., all FDMAs originate from DPAs However, the artery has other origins from the plantar arteries (2%), from the lateral tarsal artery (9,4%)

* Variations in the location related to the first dorsal interosseous muscle the rate of absent or slender FDMA is 12% in Gilbert A.’s study (1976), 18,5% in Leung P.C.’s (1983), 5% in Gautam A (2020)

In relation to the first dorsal interosseous muscle, FDMA can lie superficially (on the muscle or superficially within it) or deep (beneath the muscle) Most studies have shown that the most common type of FDMA is superficial (the artery course superficially on the muscle)

* Caliber The diameter of FDMA ranges from 1 to 1,5mm according

to many studies

* Classifications of the first dorsal metatarsal artery To simplify, many authors (Greenberg B.M (1988), Earley M.J (1989), Chávez-Abraham V (2003), Strauch B (2006), Zhu J (2006), Xu L (2016)) classified FDMA into 3 main types: superficial type, deep type, absent type like type I, II, III of Gilbert A.’s classification

1.2.2.3 First plantar metatarsal artery and its variations

FPMA can be a branch of DPA or FDMA

1.2.2.4 The communication between the first dorsal and plantar metatarsal arteries in the first toe web space and the correlation

of the blood supply to toes

Based on experience in the clinical application of toe transfers, experts from Chang Gung Memorial Hospital, Taiwan classified vascular patterns in the first toe web space into 3 types: FDMA is dominant, accounting for 70% FPMA is dominant, accounting for 20% FDMA and FPMA have similar diameters, accounting for 10%

1.2.2.5 The digital arteries

According to May J.W (1977), the average diameter of the lateral plantar digital artery of the great toe and medial plantar digital artery of the second toe are 1,1mm and 0,9mm, respectively

1.2.3 Studying the arterial anatomy of the great and second toe flaps through diagnostic imaging techniques in the world

In 2006, Zhu J conducted an anatomical study of FDMA via Doppler sonography on 374 feet The results showed that FDMA of the

374 feet all originated from DPA with an average caliver of 1 ± 0,5mm

Angiograhic methods can be catheter angiography (Leung

P.C (1983), Greenberg B.M (1988), Yamada T (1993), Upton J (1998), Cheng M.H (2006)) and minimally invasive diagnostic imaging procedure (Hou Z (2013), Xu L (2016))

In 2006, Xu L et al reported the use of CTA to preoperatively investigate the arterial supply of the toe flaps on 158 feet of 79 patients who underwent toe-to-hand transfer surgeries As a result, CTA was able to investigate clearly the types of FDMA according to Gilbert A.’s classification, thus helping the surgical process to be favorable

1.2.4 Anatomical study of the arterial supply of the great and second toe flaps in Vietnam

We have just found only two recent studies by Anatomical Department of Vietnam military medical university in 2017 and 2022

In 2022, based on the traditional dissection on 50 cadaveric feet preserved by formaldehyde embalming fluid, the authors showed the results of the origin, location, pathway of DPA, FDMA as follow:

- DPA originates mainly from the anterior tibial artery (49/50), accounting for 98%, not in (01/50) accounting for 2%; average diameter is 3.74 ± 0.69 (mm); average length 7.61 ± 1.16 cm

- FDMA originates from DPA (48/50), accounting for 96%, from the deep plantar artery (01/50) accounts for 2%, from the plantar artery arch (01/50) accounts for 2%; original diameter and end diameter: 1.84 ± 0.36 mm and 1.54 ± 0.35 mm, respectively

1.3 Applying free toe transfer for thumb reconstruction

1.3.1 In the world

In general, the basic issues related to indications of the surgery, selection of toe transfer, outcomes in reconstructed hands, and morbidity in donor foot have been systematically and detailedly mentioned

1.3.2 Results of the toe-to-thumb transfer surgery

In the evidence-based research of Lin P.Y et al in 2011, the author collected 633 english articles related to toe-to-thumb transfer surgery In which, 25 studies representing 450 toe-to-thumb transfers met the inclusion criteria They included 101 second toe transfers, 196 great toe transfers, 122 wrap-around transfers, and 31 TGT transfers for thumb reconstruction The results showed that: the average survival rate was 96,4%; no statistically significant differences could be detected between the four transfers with regards to survival, arc of motion, total active motion, grip and pinch strength, and static two-point discrimination

1.3.3 Donor site morbidity

In 2016, Sosin M did evidence-based research via 56 articles evaluating the donor foot morbidity after toe transfer The results showed that functional foot impairment could occur after various toe transfer procedures due to altered biomechanics of weight distribution

In particular, great toe transfer left more complications and impacts on the donor foot than the second toe transfer

1.3.4 New trends in toe-to-thumb transfer surgery

(1) Immediate toe-to-thumb transfer after acute hand injuries

(2) Applying diagnostic imaging techniques to preoperatively investigate the vascular pedicle of toe flaps

1.3.5 In Vietnam

Nowadays, besides 108 Military Central Hospital, numerous hospitals are performing this surgery such as Le Huu Trac National Burn Hospital, Saint Paul Hospital, Viet Duc Hospital, Ho Chi Minh Trauma and Orthopedic Hospital, 115 Hospital, Hue Central Hospital… However, the sample sizes in the reports related to the surgery were still limited and the analysis of the results was only the initial comments

Chapter 2 SUBJECTS AND METHODS

2.1 Anatomical study of the arteries supplying blood to the great and second toe flaps using 320-detector row computed tomography angiography

2.1.1 Subjects

Thirty-six Vietnamese adults with 72 intact feet underwent CTA

to investigate the arterial anatomy of the toe flaps preoperatively in the Department of Diagnostic Imaging – 108 Military Central Hospital from June 2017 to December 2019 Out of these 36 patients, 22 received toe-to-thumb transfer surgeries in 108 military central hospital

Inclusion criteria: Adults, age ≥ 18 Both ankles and feet were intact The patient did not have any diseases or injuries affecting the arterial system to both ankles and feet The patient had to agree, understand and accept the risk factors when performing CTA with contrast injection

Exclusion criteria: Pregnant and lactating women Patients with

a history of chronic cardiology diseases, diabetes, asthma, allergies

2.1.2 Method

2.1.2.1 Design: Prospective, cross-sectional study

2.1.2.2 Materials: 320-detector row CT scanner (Aquilon One,

Toshiba Medical System, Tokyo, Japan) Power injector (Medrad Stellant, Bayer, USA) Nonionic contrast agent bolus (Xenetic 350 mg/100 ml vial, Guerbet, France)

kV of tube voltage; 150 mA of tube current; field of view of 160 mm, extended from ankle to toes; gantry rotation time of 0.35 s; slice thickness of 0.5 mm, matrix of 512 × 512

- One dose of sublingual spray nitroglycerin (Egis, Hungary) (0.4 mg/time) was administered 5 min before the initiation of scanning

- A 20-gauge needle was inserted into the median cubital vein A nonionic contrast agent bolus was injected with a dose of 1.5 ml/kg, speed of 5 ml/s by a power injector

- Region of interest (ROI) was located in the first intermetatarsal space A repetitive monitor acquisition (120 kV, 10 mA, 1 s of interscan delay) started 40 s after contrast injection

- The peak contrast enhancement of FDMA was identified by the manual bolus tracking method

* Image reconstruction: Besides standard axial images, the raw data were reconstructed and transferred to maximum intensity projection, multi-planar reformation, and volume rendering images via Vitrea software, version 6.3 (Toshiba medical systems, Ottawa, Japan)

2.1.2.4 Data analysis

The anatomical features (origin, pathway, length, and diameter) of the DPA, FDMA, FPMA, deep plantar arch, AsFTWS were identified and measured on 2D, 3D images via Vitrea software, version 6.3 The diameter of these arteries was measured at their origin and termination on the planes perpendicular to the arterial wall

28 patients underwent great and second to transfer for thum reconstruction from January 2011 to May 2017

Inclusion criteria: Patients had sufficient records including medical records, films, pre and post - operative figures; were examined and evaluated postoperative results by a fiexe group of specialists Following-up time on each patient ≥ 12 months

Exclusion criteria: Patients were lost to follow-up (did not partice postoperative exercises according to instructions, did not return for evaluation)

- Exclusion criteria: The hand lost the thumb combining with 3-4 long fingers (metacarpal hand or metacarpal like hand) Pregnant and lactating women

2.2.2 Method

2.2.2.1 Design: Retrospective combined prospective study

Observational, cross-sectional study

2.2.2.2 Process of toe-to-thumb transfer surgery

* Thumb amputation preserving thenar muscles

- Technique of second toe-to-thumb transfer (according to the procedure of Manktelow R.T.)

- Technique of TGT-to-thumb transfer (according to the procedure of

2.2.2.4 Evaluating postoperative results

A Characteristics of the study group

B Primary results (Postoperative period ≤ 3 months)

- Survival rate: Complete survival, Partial necrosis, Death

- Complications and management

C Secondary results (at the last evaluation, postoperative period

≥ 12 months)

* In reconstructed hand:

- Scar condition was evaluated: soft, hypertrophic, and ulcer

- Motor function was evaluated

- The sensory of the transferred toe was evaluated

- Aesthetic and functional drawbacks, complications (such as tendon adhesions, stiffness, and others) were looked for

- Bony status (the axis, bone union) were checked through X-ray films

- Hand function was evalutated based on patient-reported outcomes (questionnaires) Two questionnaires were used: Quick disabilities of arm, shoulder and hand (QuickDASH) and Michigan Hand outcomes questionnaire (MHQ)

* Evaluating the morbidity of the donor foot: Scar condition was

evaluated: soft, hypertrophic, and ulcer Abilities (walking, going stairs up and down, running, toe walking, high knee running, and playing sport) were evaluated Balance capacity was evaluated through measurement of standing time with eye closure on operated

foot and compare with normal non-operated foot The change of foot dimension was identified by finding the change in footwear or patient’s feeling when wearing shoes and comparing with a normal non-operated foot New foot callus, pain point, cold intolerance were looked for Complications, deformity of the adjacent toe were looked for through clinical examination and X-ray Foot function was accessed based on the foot and ankle disability index (FADI) questionnaire

- The age average was 32,0 years (19 – 59 years)

- The male-to-female ratio was 31/5 (86,2% / 13,8%)

3.1.2 Dorsalis pedis artery

- The present rate of DPA was: 67/72 (93,1%)

- In almost cases (91,7%), DPA ran in the middle third of the ankle from the mid-point between two malleoli to the posterior end of the first intermetatarsal space In one case (1,4%), the artery deviated to the lateral third of the ankle, from the lateral malleolus to the posterior end of the first intermetatarsal space

- In 67 feet where DPAs were present: the diameter at the origin: 3,22

± 0,59mm (2,0 – 4,5mm); the diameter at the termination: 2,56 ± 0,51mm (1,5 – 3,6mm)