40: Correction of Constriction Ring

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Procedure 40 Correction of Constriction Ring

Pao-Yuan Lin, Sandeep J. Sebastin, Kevin C. Chung

imageSee Video 33: Surgery for Constriction Band Syndrome

Indications

image Constriction rings may be mild, moderate, or severe.

• Mild: Only skin and a portion of subcutaneous fat are involved, and there is no lymphedema.
• Moderate: The lymphatic channels are interrupted, but the vascular system is intact. Lymphedema can be seen in the portion distal to the constriction ring.
• Severe: The constriction ring interrupts the vascular system so that the distal blood supply is jeopardized and the part distal to the constriction ring is at risk for gangrene.

image Severe constriction rings will need release soon after birth on an emergent basis. Moderate rings can be corrected at a later age (6 to 9 months), when anesthesia is easier and safer and the structures are larger. The correction of mild rings is performed for aesthetic considerations and should be done before the child goes to school (3 to 4 years of age).

Examination/Imaging

Clinical Examination

image The presence of distal lymphedema indicates a lack of sufficient subcutaneous layer to promote the lymphatic flow. Most of the lymphedema will subside within a few months after correction of the constriction ring.

image In children with bilateral constriction ring syndrome, the severity of the deformity of one limb is independent of the other.

Imaging

image Plain radiographs of the affected limb can help identify any associated bony anomalies, especially when the constriction ring is associated with acrosyndactyly.

Surgical Anatomy

image The constriction ring can extend from the skin to as deep as the bone. Affected structures may involve lymphatics, nerves, and the vascular system, and the constriction ring can result in lymphedema, neurologic symptoms, and amputation.

image The soft tissue and skeletal structures are always normal proximal to the constriction ring, but the soft tissue distal to the ring can present with varying degrees of edema (Fig. 40-1A). The growth centers distal to and just proximal to the constriction can often be injured, resulting in hypoplasia. Nerve palsies have been associated with the bands and are present at birth.

image Excess subcutaneous fat both proximal and distal to the constriction ring should be excised.

image The arterial blood supply of the part distal to the constriction ring arises from perforators that originate from the main artery located in the deep layer. This blood supply can be maintained because of the intact main artery and its venae comitantes (Fig. 40-1B).

image

FIGURE 40-1

Positioning

image The procedure is performed under general anesthesia and tourniquet control. The patient is positioned supine with the affected upper extremity on a hand table.

Exposures

image The key principles in surgical correction of constriction rings are the following:

• The constriction ring is excised, and a Z-plasty is used to transpose skin flaps to prevent a circular scar contracture.
• Excessive subcutaneous fat is excised and/or transposed to correct the contour deformities.

Pearls

For constriction rings of the digits, staged correction is safer. One-stage correction in digits has a greater chance of injuring the vessels and jeopardizing the distal circulation. One-stage correction with circumferential excision of a constriction ring can be performed in the proximal limbs, where injury of deep arterial and venous vessels is less likely.

Procedure

Correction of Finger Constriction Rings

Step 1: Design of Skin Flaps

image A single Z-plasty is sufficient for correction of finger constriction rings because a one-stage correction is not planned. Either this may be designed on the dorsum, or two single Z-plasties can be designed on both midlateral lines of the finger (Fig. 40-2).

image

FIGURE 40-2

Step 1 Pearls

In finger circumferential rings, it is better to address the dorsal portion first because this improves the aesthetic appearance, and the patient may not need a second stage.

Step 2: Excision of Constriction Ring and Elevation of Skin Flaps

image The constriction ring is incised, and skin flaps are elevated along with a thin layer of fat. This preserves the subdermal plexus and maintains viability of the skin flaps (Fig. 40-3).

image

FIGURE 40-3

Step 2 Pitfalls

It is unnecessary to excise the constriction ring; instead, use the skin for closure to avoid skin deficiency during dorsal skin closure.

If the constricted ring involves the palmar side, meticulous dissection should be done to avoid injuring the neurovascular bundles.

Step 3: Excision of Excess Subcutaneous Fat

image The subcutaneous fat is elevated proximally and distally superficial to the extensor tendon paratenon or the flexor tendon sheath (Fig. 40-4A and B).

image Excessive dorsal fat, usually on the distal side, should be removed for correction of contour deformity.

image The fat flaps are separated from the skin and sutured to each other using 4-0 Vicryl to correct the contour deformity (Fig. 40-4C).

image

FIGURE 40-4

Step 4: Transposition and Suture of Z-Plasty Skin Flaps

image Z-plasty skin flaps are transposed and sutured using 4-0/5-0 chromic catgut (Fig. 40-5).

image

FIGURE 40-5

Procedure

Correction of Proximal Limb Constriction Rings

Step 1: Design of Skin Flaps

image Multiple Z-plasty design is used for correction of proximal limb constriction rings because they can be corrected in a single stage (Fig. 40-6A).

image

FIGURE 40-6

Step 1 Pearls

Multiple Z-plasties can be constructed in two ways. In a parallel construction, a quadrilateral flap is transposed into a triangular defect, and this results in the formation of dog-ears. A skew construction avoids the formation of dog-ears but results in formation of a broad-tipped flap with a relatively narrow base (Fig. 40-6B).

Step 2: Excision of Constriction Ring and Elevation of Skin Flaps

image The constriction ring is incised, and skin flaps are elevated.

image Unlike for finger constriction rings, the skin flaps are elevated along with full thickness of the subcutaneous fat in a plane superficial to the deep fascia.

Step 3: Transposition and Suture of Z-Plasty Skin Flaps

image Z-plasty skin flaps are transposed and sutured using 4-0/5-0 chromic catgut (Fig. 40-7).

image Correction of dog-ears may be required if a parallel construction was used for multiple Z-plasties.

image

FIGURE 40-7

Postoperative Care and Expected Outcomes

image A soft bulk dressing is applied on the wound. The child’s mobility is not restricted postoperatively.

image The lymphedema of the distal part of the affected limb will improve significantly within a few weeks of the surgery, and the contour deformity will improve.

image Figure 40-8 shows the results of the correction of proximal limb constriction rings at 4 months’ follow-up.

image

FIGURE 40-8

Evidence

Greene WB. One-stage release of congenital circumferential constriction bands. J Bone Joint Surg [Am]. 1993;75:650-655.

In this study, three patients underwent single-stage release of circumferential constriction ring. No wound problems occurred, even when there had been marked swelling of the extremity distal to the band. The single-stage release facilitated postoperative care, and there was no need for additional periods of anesthesia or for additional operations. (Level V evidence)

Upton J, Tan C. Correction of constriction rings. J Hand Surg [Am]. 1991;16:947-953.

A retrospective study of 116 constriction rings in 58 patients who underwent correction of deep and shallow constriction rings. All excellent results occurred in patients with shallow deformities. Improvement of contour was seen; 64% were graded as excellent, 31% as good, and only 5% as poor. (Level IV evidence)

Visuthikosol V, Hompuem T. Constriction band syndrome. Ann Plast Surg. 1988;21:489-495.

A retrospective chart review of 30 cases of constriction band syndrome diagnosed and treated during 1973 to 1986 was conducted. All 30 cases were treated with single-stage Z-plasty surgery. Good results were achieved in 16 of 20 patients with constriction alone. No compromised circulation of the distal limb or total flap loss was encountered in this study. (Level IV evidence)

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Procedure 40 Correction of Constriction Ring

Pao-Yuan Lin, Sandeep J. Sebastin, Kevin C. Chung

imageSee Video 33: Surgery for Constriction Band Syndrome

Indications

image Constriction rings may be mild, moderate, or severe.

• Mild: Only skin and a portion of subcutaneous fat are involved, and there is no lymphedema.
• Moderate: The lymphatic channels are interrupted, but the vascular system is intact. Lymphedema can be seen in the portion distal to the constriction ring.
• Severe: The constriction ring interrupts the vascular system so that the distal blood supply is jeopardized and the part distal to the constriction ring is at risk for gangrene.

image Severe constriction rings will need release soon after birth on an emergent basis. Moderate rings can be corrected at a later age (6 to 9 months), when anesthesia is easier and safer and the structures are larger. The correction of mild rings is performed for aesthetic considerations and should be done before the child goes to school (3 to 4 years of age).

Examination/Imaging

Clinical Examination

image The presence of distal lymphedema indicates a lack of sufficient subcutaneous layer to promote the lymphatic flow. Most of the lymphedema will subside within a few months after correction of the constriction ring.

image In children with bilateral constriction ring syndrome, the severity of the deformity of one limb is independent of the other.

Imaging

image Plain radiographs of the affected limb can help identify any associated bony anomalies, especially when the constriction ring is associated with acrosyndactyly.

Surgical Anatomy

image The constriction ring can extend from the skin to as deep as the bone. Affected structures may involve lymphatics, nerves, and the vascular system, and the constriction ring can result in lymphedema, neurologic symptoms, and amputation.

image The soft tissue and skeletal structures are always normal proximal to the constriction ring, but the soft tissue distal to the ring can present with varying degrees of edema (Fig. 40-1A). The growth centers distal to and just proximal to the constriction can often be injured, resulting in hypoplasia. Nerve palsies have been associated with the bands and are present at birth.

image Excess subcutaneous fat both proximal and distal to the constriction ring should be excised.

image The arterial blood supply of the part distal to the constriction ring arises from perforators that originate from the main artery located in the deep layer. This blood supply can be maintained because of the intact main artery and its venae comitantes (Fig. 40-1B).

image

FIGURE 40-1

Positioning

image The procedure is performed under general anesthesia and tourniquet control. The patient is positioned supine with the affected upper extremity on a hand table.

Exposures

image The key principles in surgical correction of constriction rings are the following:

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