Surgical Neurolog

Technique

Training of A3-A3 side-to-side anastomosis in a deep corridor using

a box with 6.5-cm depth: technical note

Tomohiro Inoue, MD, Kazuo Tsutsumi, MD4, Kuniaki Saito, MD, Shinobu Adachi, MD,

Shota Tanaka, MD, Naoto Kunii, MDDepartment of Neurosurgery, Showa General Hospital, Tokyo 187-8510, Japan

Received 23 February 2006; accepted 4 March 2006

Abstract Background: Cerebral revascularization in the deep surgical field is technically challenging.

www.surgicalneurology-online.com

0090-3019/$ – see fro

doi:10.1016/j.surneu.2

Abbreviations: OA

artery; SCA, superior

4 Corresponding a

E-mail address: k

Especially, side-to-side anastomosis like A3-A3 could be technically more difficult compared with

end-to-side anastomosis. To improve surgeon’s dexterity and maneuverability in the deep surgical

field, the authors developed an easily accessible and well-simulating training system using prosthetic

tubes and a box.

Methods: Two prosthetic tubes (silicon tube, 1.2 mm in diameter) are mounted in parallel on the

bottom of 6.5-cm-deep emptied dtissue paper box.T The orifice of the box is restricted to 2 � 2 cm to

simulate a deep and narrow surgical corridor. Using bayonet-shaped micro needle holder and forceps,

the side-to-side anastomosis of the tubes is performed with 10-0 nylon under operative microscope.

Results: Prosthetic tubes well simulated real A3-A3 anastomosis. From the standpoint of technical

difficulty, this training system needed slightly higher level of dexterity compared with real A3-A3

anastomosis because of narrower and deeper surgical corridor, and the wall of prosthetic tube was

slightly thicker and more inflexible. After this training, the surgical technique in real A3-A3

anastomosis was improved.

Conclusions: This training system worked well to ease the transition from anastomosis in shallow

surgical field to deep and narrow surgical field. The prosthetic tube we used approximates real A3

relatively well, and the ease in setting up this system enabled repeated practice, which resulted in

steep learning curve of the technique.

D 2006 Elsevier Inc. All rights reserved.

Keywords: Cerebral revascularization; Training; Side-to-side anastomosis

1. Introduction

Cerebral revascularization in deep surgical field remains

a critical part of the neurosurgical skill for treating complex

aneurysm and very rarely atherosclerotic occlusive cerebro-

vascular disease. Because of the inherent difficulty of this

technique, as well as the limited surgical case volumes, only

some experienced neurosurgeons perform this technique.

Here, we present a unique microsurgical training system in

deep surgical field that is easy to set up and works as an

nt matter D 2006 Elsevier Inc. All rights reserved.

006.03.035

, occipital artery; PICA, posterior inferior cerebral

cerebellar artery; STA, superficial temporal artery.

uthor. Tel.: +81 424 61 0052; fax: +81 424 64 7912.

.tsutsumi-md@nifty.com (K. Tsutsumi).

adjunct to transit from anastomosis in shallow surgical field

to deep and narrow surgical field.

2. Materials and methods

An emptied dtissue paper boxT with depth of 6.5 cm is

used. Because the longest bayonet-shaped (bent-knee–

shaped) micro forceps available that can handle the needle

and thread of a 10-0 nylon is 7 cm long from the tip to

the angle of knee, we choose this size of box. In addition,

we expect that this depth probably covers most of the

neurosurgical deep anastomosis. The orifice of the tissue

paper box is restricted to 2 � 2 cm, which is as narrow as

y 66 (2006) 638–641

T. Inoue et al. / Surgical Neurology 66 (2006) 638–641 639

a 1-yen Japanese coin, with rigid tape (Fig. 1). In this

condition, if we use straight instruments, the hands or

fingers will shadow the surgical field under the operative

microscope. Only when the bayonet-shaped instruments

are used bilaterally, will dshadowingT not happen in higher

magnification. Two prosthetic silicon tubes of 1.2-mm

diameter (Fujita, Tokyo, Japan) are mounted in parallel on

the gauze for side-to-side anastomosis at the bottom of

the box by just passing each end of the tube under the

fiber of gauze. The usual surgical skin marker can be used

to visualize well the orifice of the darteriotomy.T Slightly

internally curved incision is made with curved micro-

scissors on both tubes. Firstly, with a 10-0 nylon, the

running suture of the back wall is performed (Fig. 2), with

the first stitch passed from outside to the inside on the left

tube and the last stitch passed from inside to the outside

on the right tube (in the case of a right-handed surgeon).

Both ends of the thread of the running suture are pulled

gently to tighten once. Then, the stay suture is performed

on each end of arteriotomy, and the threads of stay

suture’s knots are left in some length. After tightening the

running suture by pulling both ends of the thread again,

Fig. 1. The suturing training is performed at the bottom of 6.5-cm-deep box

through the orifice as narrow as a 1 yen Japanese coin (2 cm in diameter)

with bilateral bayonet-shaped micro instruments (top). The training

condition is simulating the real A3-A3 anastomosis well (bottom).

Fig. 2. During suturing the back wall in the training (top) and in the real

A3-A3 anastomosis (bottom).

these are tied to each side of thread of the stay suture’s

knot (Fig. 3). The anterior wall is then sutured with in-

terrupted stitches (Fig. 4).

3. Result

The bottom part of Figs. 1-4 shows real A3-A3

anastomosis operation of a 67-year-old woman with a right

A2 atherosclerotic occlusion with hemodynamic ischemia.

In this operation, the 9-0 nylon was used so that the running

suture of the back wall will not tear. In this patient, the site

suitable for anastomosis was just below the bridging vein,

and the depth and narrowness of the surgical corridor made

it slightly more difficult than the usual A3-A3 anastomosis.

The training system illustrated here well simulated this

condition (Fig. 1). In addition, this training needed a slightly

higher level of dexterity compared with real A3-A3

anastomosis because of the narrower and deeper surgical

corridor, and the wall of the prosthetic tube was slightly

thicker and more inflexible. After repeated training with this

setting, the occlusion time of the above-mentioned A3-A3

operation was 35 minutes, which is remarkably shortened

compared with the previous occlusion time of 55 minutes

T. Inoue et al. / Surgical Neurology 66 (2006) 638–641640

(in the operation of ruptured giant anterior communicating

artery aneurysm).

4. Discussion

Although the international cooperative study of external/

internal arterial anastomosis published in 1985 brought

about a decrease of microvascular cerebral revascularization

[2], the subset of aneurysm with complex anatomy, skull

base tumors and some very restricted atherosclerotic

cerebrovascular occlusive cases still require this technique

[5,11]. Various training methods have been developed to

overcome difficult circumstances with lowered surgical

volume and to improve revascularization technique

[1,3,4,6-10,12,13]. We also developed a basic anastomosis

training system that we are doing routinely [14]. However,

the training of anastomosis in the deep and narrow corridor

has not been well discussed despite the challenging nature

of this technique even after the mastery of anastomosis in

the shallow surgical field.

We developed this training system as an adjunct to ease the

transition from anastomosis in the shallow surgical field to

the deep and narrow surgical field. Firstly, we simply sutured

Fig. 3. Confirming the status of the back wall after completion of running

suture and stay suture in the training (top) and in the real A3-A3

anastomosis (bottom).

Fig. 4. The anterior wall is sutured with interrupted stitches in the training

(top) and in the real A3-A3 anastomosis (bottom).

the neighboring fibers of the gauze at the bottom of the

6.5-cm-deep box with a 10-0 nylon through the orifice

approximately 3 � 3 cm with the bayonet-shaped micro

needle holder in the dominant hand and the straight forceps in

the nondominant hand. This training was also very effective

as long as the superficial temporal artery–M2 anastomosis or

occipital artery–posterior inferior cerebellar artery anasto-

mosis was concerned. However, in some superficial temporal

artery–superior cerebellar artery anastomosis or in revascu-

larization of the P2 area, the situation wherein the surgical

corridor is so narrow and deep that maneuverability of the

nondominant hand with the straight forceps was restricted

and that the straight forceps shadowed the surgical field

presented. In addition, in the A3-A3 anastomosis, we

encountered the situation in which the corridor was narrower

and deeper compared with the usual A3-A3 anastomosis at

the corner of genu because of the distribution of bridging

vein. After experiencing those difficulties, we restricted the

orifice of the box to 2� 2 cm, in which the bilateral bayonet-

shaped micro instruments could avoid shadowing. During the

training course, special attention was paid to improve the

maneuverability of the nondominant hand with the bayonet-

shaped forceps that are apparently more difficult to deal with

than straight forceps. The reason why we used side-to-side

T. Inoue et al. / Surgical Neurology 66 (2006) 638–641 641

anastomosis in the training system was that this technique

needed a higher level of dexterity from the standpoint of

anastomosis itself, such as bilateral curved arteriotomy and

running suture of the back wall, compared with end-to-side

anastomosis. The prosthetic tube was used simply because

the animal model was not available in our institution.

However, the prosthetic tube we used simulated the real A3

well as for the caliber and the thickness of the wall. In

addition, this tubing is somewhat more inflexible than the real

A3 wall, which resulted in a slightly higher demand of

dexterity during suturing training. This inherent nature of the

prosthetic wall provided the good occasion to master a

precise controlled stabilization of the vessel wall by the

forceps held in the nondominant hand.

The balance of the ease to set up and the adequacy in

simulating clinical setting are the important aspects of the

training system. Our system apparently has a disadvantage

in simulating live anastomosis compared with the animal

model. However, once the definite anastomosis technique

with high patency rate is accomplished in the shallow

surgical field, the higher level of dexterity that is inherent to

the deep and narrow corridor itself would be the most

essential element of the training system. As the technical

difficulty increases, the repeated practice would be neces-

sary as well. From those standpoints, we believe that our

training system, which simulates the most difficult condition

and is easy to set up, would contribute to the acquisition and

refinement of skills in deep anastomosis.

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