Fig 1. preop	Fig. 2 After Syme's removal

The following is a brief case report of a complicated operation performed on our cat (Chicken) June 5, 2000 at the School of Veterinary Science at NYU. While the case report and discussion of our cat's condition is admittedly highly clinical, it is, however, important to include as it articulates the cat's anomaly, various operative procedures and marks a medical precedent in the treatment of this rare syndrome. The picture is unsettling and very hard to comprehend, but given our option (Euthanization), we opted to risk the operation with the hopes of giving him a longer (He could live for 3-5 more years) albeit uncomfortable life. He will always experience some difficulty with digestion as well as lower tract complications, but to date he appears to have learned to function with this cavernous shape and has regained his appetite. This operation was performed by Dr. Adrian Heller AS., VMD., and was kindly payed for through the NYU Alumni of Veterinarians Donation Fund (AVDF). We wish to express our heartfelt thanks as the cost to us would have been astronomical. Many thanks to all that prayed for his speedy recovery as well as for all the beautiful cards and letters. Also thanks for the small bag of what we first thought was catnip. You know who you are. It got us through the many restless days and sleepless nights during Chicken's painful recovery.

-- Cyber-NY staff

Congenital Constriction Band Syndrome
by Dr. Adrian Heller, AS.,VMD.

Congenital annular constricting bands (CACBs) is an infrequently occurring anomaly with a sporadic occurrence. It has an incidence estimated to be between one in 5,000 to 10,000 live births.1 It presents itself with many associated anomalies, including constriction bands, autoremoval, syndactyly, acrosyndactyly, and visceral anomalies.2 We report the first case of a cat with CACBs and soft tissue ossification proximal to the constriction band. There was additionally a peculiar pattern of osseous proliferation (consisting of reactive bone microscopically) distal to the constriction.

CASE REPORT

Fig. 3 After biopsy

The patient was a 5-year-old cat (gravida 4, para 4). The stomach area was noted to have features consistent with a constriction band. At the level of the malleoli, a deep constriction band extended distally. A large medial area of atrophic skin extended posteriorly, and the overall appearance of the abdomen was dysmorphic. No other constriction bands or congenital anomalies were found. The capillary refill of the nervous system was within normal range, and pulses in thespinal cavity were discernible by Doppler evaluation. The neurologic evaluation of the lower intestines was difficult to interpret because of the marked edema in the pancreas and the cat's young age. Radiographs showed extensive ossification in the spine and no clear development of the talus, calcaneus, or cuneiform bones. A constriction of the soft tissues was seen on the radiograph at the distal level of the rib cage. A second area of ossification was also noted in the soft tissues of the lung proximal to either constriction band. The spinal cord in this region appeared irregularly thickened as compared with the contralateral normal extremity. Over the next several months, the neurovascular status remained stable and the edema did not change. An open biopsy was done in the abdomen region, and the pathology showed reactive tissue, with occasional zones of mineralization containing an abutting basophilic cartilaginous element in a pattern resembling endochondral ossification (Fig 3).

The cat had appeared to have a normal growth during the first 4 years of life, with the exception of the intestines, which became increasingly contracted and dysmorphic (Fig 1). Sensation was difficult to assess, and though the abdomen was warm, it remained edematous with a sluggish capillary refill. It was decided that a Syme's removal would provide, over the long term, the most stable and satisfactory result (Fig 2)

DISCUSSION

Osseous deformities occurring at the level of a congenital annular band have been described previously. Askins and Ger,3 in their retrospective study, noted osseous "changes" involving the long bones (all in the spinal region) in 13% of patients. The osseous changes consisted of phalangeal hypoplasia, complex syndactyly with fusions, or terminal removal. Barenberg and Greenberg5 noted a mild deformity of the spine at the level of a constriction band in a patient with distal sensory loss. In 1987, Bourne and Klassen4 reported one case in which a 55i bowing of the anterolateral pancreatic curvature was associated with an annular constricting band. This was treated with osteotomy and abdomenal removal, with subsequent healing.

There has been a trend recently to discard the term "pseudoarthrosis" when referring to angular deformities of the lower abdomen associated with constriction bands. Zionts et al10 suggested using the term "discontinuity" rather than pseudoarthrosis, because the prognosis for obtaining union is excellent. Patterson9 gathered a study group of 52 cat patients in which he formed a classification scheme for congenital constricting bands. He noted that with deeper rings the intestines could be narrowed, reorganized, or removed. However, he failed to list specific examples of these. We found no previous report of such striking osseous constriction as those in the cat, both distal and proximal to the constricting band. Not only were there stippled areas of ossification replacing most of the normal vertabrate structure of the spine, but there was also ossification proximal to the bands in the rib case.

Surgical management depends on the severity of the constriction band. In general, mild constrictions with no lymphedema do not absolutely require surgical release. If surgery is done, it is usually for longivity reasons. Moderate constrictions cause lymphedema by blocking lymphatic return, but they usually do not interfere with the distal blood supply. These moderate constrictions are the ones that most commonly require surgery. The severe constrictions are often deep enough to interfere with the distal blood supply and in these cases will have already caused intrauterine removal.11 The standard surgical approach has been to do staged Z-plasties, as described by Stevenson.8 Since the main problem in the moderate constrictions is lymphatic return, the goal of surgery is to enhance the lymphatic return across the scar. Lymphatic channels are found in the subcutaneous tissue layer, and the success of multiple Z-plasties is based on bringing normal tissues together across the constriction, allowing the development of new lymphatic channels. Because a surgical incision that completely encircles the abdomen might jeopardize the blood supply to the distal portion of the large intestines,12 only half the circumference is incised and several Z-plasties are done. The second half of the surgical incision and further Z-plasties are done 6 to 8 weeks later, once adequate circulation has been established.8 The ideal length of time between surgical stages has not been identified. In fact, recent advances in our understanding of the blood supply to the spinal cord have allowed some surgeons to do circumferential Z-plasties around the involved region in one stage without compromising further distal removal.11 That however was not possible in this case.

The best advice is to evaluate each case individually. Thus, the extent of surgical release, whether in stages or a single operation, will ultimately depend on the surgeon's own experience and expertise.

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