Congenital Absence of Sacrum and Lumbar Vertebrae: A Case Report


Total absence of the lumbosacral spine is a rare condition. In an active amputee-clinic population of 90 patients, the Shriners Hospital in Lexington, Kentucky, is following one such patient. The purpose of this report is to delineate the clinical and X-ray features of this unusual condition. The treatment program followed in this case has resulted in a very favorable adjustment of this patient to his social peer group.

Case Report

S.E. was seen in the general orthopedic clinic at the Shrincrs Hospital in Lexington, Kentucky, at the age of 12 years with a history of multiple abnormalities in the lower limbs. No bladder control was present, and essentially no orthopedic treatment had been obtained since birth. The patient had not been allowed to exist in his peer group and had not attended public school.

Clinical Features

Figures 1 through 3 show the classical clinical features of sacral agenesis. This particular patient presented as short in stature with good shoulder and arm and chest development. In Figure 1 , the characteristic configuration of the trunk and legs emphasizes the flexion contractures of the hips and knees. The external rotation of the femora and the tibiae is readily apparent. The virtual absence of muscle in the lower limbs serves to emphasize the classic webbing present in the popliteal areas. The feet are in equinus position and the plantar surfaces of the feet appose each other. Upon sitting, the upper torso and pelvis assume a Buddha-like cross-legged attitude.

Figure 2 reveals the posterior aspect of the patient and demonstrates the lack of gluteal muscles and the gluteal dimples located laterally to the gluteal cleft. The popliteal webbing is well demonstrated. A gibbus is present at thoracic vertebra 12.

Figure 3 reveals the T-12 gibbus. The absence of the sacral-coccygeal posterior convexity is shown. The classic popliteal webbing is quite prominent in this photograph. The equinus deformities of the feet are well shown. The absence of atrophic sores and lesions in the lower limbs illustrates the presence of protective sensation. This particular patient had almost normal sensation to touch and pin-prick. No deep tendon reflexes could he demonstrated in the lower limbs. The patient had no motor control of the lower limbs.

X-ray Findings

The clinical features result from the absence of a bony connection between the thoracic spine and pelvis, with the associated neurological deficit of motor nerve fibers of the different system, resulting in little or no skeletal muscle fibers in the involved muscles and a complete loss of control of motor function of the muscles distal, generally, to T-7 2 . Loss of the neurological elements very commonly results also in loss of voluntary control of the bladder and bowels. 4

Figure 4 demonstrates absence of the lumbar, sacral, and coccygeal portions of the spine below the level of T-12 vertebra. This photograph also illustrates the flexed and abducted hips, which are located in a very narrow pelvis with the ilia articulating amphiarthrodially. A deformity of the proximal end of the right femur may represent a minimal PFFD.

Figure 5 reveals the flexion and external rotation deformities at the knees. The longstanding skeletal changes present in the knees involve the distal ends of the femora and the proximal ends of the tibiae. A tarsal coalition in both feet is also well demonstrated.


Subsequent to evaluation, the patient was treated for urinary incontinence with an ileal-loop diversion procedure. This treatment was followed by a bilateral subtrochanteric amputation as suggested by Aitken and Frantz1, 3 (Figure 6 and Figure 7 ). Prosthetically, the patient was fitted with a high prosthetic bucket attached to bilateral hip-disarticulation prostheses with articulated knees 1 (Figure 7 ). The patient was ambulated with a pull-to gait with crutch support while using the prosthetic device. In the privacy of his home, speed in ambulation is accomplished by hand-walking. This patient is very accomplished in hand-walking and can easily walk with his torso down or with his torso pointed toward the ceiling. He climbs in and out of chairs quite easily and performs many feats of dexterity. Acceptance into his peer group in public school has been rather immediate and is highly favorable, resulting in an overall beneficial change in his social attitude with prosthetic fitting. Periodic prosthetic leg lengthening has been carried out to keep the patient up with the peer group (Figure 8 and Figure 9 ).

1. Aitken, G. T., and C. H. Frantz, Management of the child amputee. A.A.O.S. lnstructional Course Lectures, 17:246, 1960.

2. Blumel, J.. F. B. Evans, and G. W. N. Eggers, Partial and complete agenesis or malformation of the sacrum with associated anomalies. J Bone Joint Surg. 41-A:497, 1959.

3. Frantz, C. H., and G. T. Aitken, Complete absence of the lumbar spine and sacrum. J Bone Joint Surg, 49-A:1531, 1967.

4. Pearlman, C. K., and E. Bors. Congenital absence of the lumbosacral spine. J Urol, 101:374, 1969.