• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Home
  • About
  • Newsletter/Updates
  • Contact Us
  • Policies

Bone and Spine

Orthopedic health, conditions and treatment

  • General Ortho
  • Procedures
  • Spine
  • Upper Limb
  • Lower Limb
  • Pain
  • Trauma
  • Tumors

Sacral Agenesis

By Dr Arun Pal Singh

In this article
    • Types
    • Etiology of Sacral Agenesis
    • Clinical Presentation
      • Type I
      • Type II
      • Type III
      • Type IV
    • Treatment of Sacral Agenesis
      • Related

Sacral [or lumbosacral agenesis in severe cases where lumbar spine is also involved] characterized by the absence of the variable portion of the caudal portion of the spine. It is a very rare deformity.

Patients with this deformity lack motor function at the affected vertebral level and sensory functions below the affected level.

It is also known as

  • Caudal dysplasia
  • Caudal dysplasia sequence
  • Caudal regression syndrome
  • Sacral regression
  • Lumbosacral agenesis

Types

Renshaw classification divides the condition into four groups depending on the amount of sacrum remaining and the characteristics of the articulation between the spine and the pelvis

Type I – Partial or total unilateral sacral agenesis

TYPE I Sacral Agenesis

Type II – Partial sacral agenesis with a bilaterally symmetrical defect, a normal or hypoplastic sacral vertebra, and a stable articulation between the ilia and the first sacral vertebra.

 

Type III – Variable lumbar and total sacral agenesis, with the ilia articulating with the sides of the lowest vertebra present.

TYPE III Sacral Agenesis

Type IV – Variable lumbar and total sacral agenesis, with the caudal endplate of the lowest vertebra resting above either fused ilia or an iliac amphiarthrosis.

 

Type II defects are most common, and type I are least common. Types I and II usually have a stable vertebral-pelvic articulation, whereas types III and IV produce instability and possibly a progressive kyphosis.

Etiology of Sacral Agenesis

The exact etiology of sacral agenesis is unknown. Maternal diabetes is the risk factor. Exposure to organic solvents in early pregnancy may increase the incidence.

Renshaw postulated that the condition is teratogenically induced or is a spontaneous genetic mutation that predisposes to or causes failure of embryonic induction of the caudal notochord sheath and ventral spinal cord. The dorsal ganglia and the dorsal portion of the spinal cord continue to develop. The dorsal ganglia and the dorsal portion of the spinal cord have been derived from the neural crest tissue and thus the sensory deficit is distal to the motor level.

Clinical Presentation

The clinical appearance of sacral agenesis patient ranges from one of the severe deformities of the pelvis and lower extremities to no deformity at all.

Patients with partial sacral or coccygeal agenesis may have no symptoms.

Other associated deformities are foot deformities, knee flexion contractures with popliteal wedging, hip flexion contractures, hip dislocations, spinal-pelvic instability, and scoliosis.

The posture of the lower extremities has been compared with a Sitting Buddha (see image below).

Sacral Agenesis-sitting-Buddha posture

Anomalies in the genitourinary system and the rectal area, are common.

Examination of the back reveals a bone prominence representing the last vertebral segment and may reveal gross motion between this vertebral prominence and the pelvis. Flexion and extension may be found to occur at the junction of the spine and pelvis rather than at the hips.

Neurological examination usually reveals intact motor power down to the level of the lowest vertebral body that has pedicles. Sensation, however, is present down to more distal levels.  Bladder and bowel control often is impaired.

Presentation depending on the severity is considered as follows

Type I

The vertebropelvic articulation is usually stable. The unilateral absence of the sacrum results in an oblique lumbosacral joint and a nonprogressive lumbar scoliosis. A calcaneovarus deformity of the foot may be present. Sensory loss corresponding to involved sacral roots may be present.

Type II

The vertebropelvic junction is stable if associated myelomeningocele is not present. Progressive scoliosis from associated congenital anomalies of the spine may occur.

Motor paralysis is present and sensation usually is normal. Anesthesia may be present at S4 level or distal. Motor and sensory loss is higher in patients 2ith associated myelomeningocele.

Unilateral or bilateral hip dislocation can occur in this type. Most patients are ambulatory.

Type III

The lumbopelvic junction is relatively stable and progressive kyphosis and scoliosis may develop especially when associated myelomeningocele is present.

The buttocks are flattened, the cleft is shortened, and each buttock is dimpled lateral to the cleft. The normal convexity of the sacrococcygeal region is lost. Hip dislocation, knee contracture, and foot deformity are common. This group of patients is not able to walk or stand without support

Type IV

There is a complete absence of the lumbar spine and sacrum. Patients are of short stature with loss of normal convexity of sacrococcygeal joint and there is a disproportion in thorax and pelvis.

The pelvis is very unstable and tends to roll up under the thorax and drop forward.

Severe kyphosis and scoliosis are common and require surgical treatment for stabilization. These patients have no bladder or bowel control and show almost all associated deformities as mentioned before.

This group of patients requires spinal-pelvic stabilization or extensive orthotic support to ambulate.

Treatment of Sacral Agenesis

Type I and II patients [partial or complete absence of the sacrum] have an excellent chance of becoming community ambulators. Foot and knee deformities in these patients should be corrected.

Management of types III and IV type deformities is more controversial.

Nonprogressive kyphosis or scoliosis do not require any treatment whereas progressive scoliosis or kyphosis requires operative stabilization.

The treatment of spinal-pelvic instability is controversial.  The patient with spine-pelvic instability is unable to sit without support or to ambulate without the aid of a pelvic-thoracic bucket.  spinal-pelvic fusion can help these patients but does not seem justified for asymptomatic spinal-pelvic instability.  If the progressive deformity is present, lumbopelvic arthrodesis [Fusion of the lumbar spine with pelvis] is recommended.

Reconstruction of the lower limb in type IV sacral agenesis has not been successful, because of the absence of muscle fibers and major motor nerves. Bilateral subtrochanteric amputation followed by fitting of a pelvic-thoracic bucket and a hip disarticulation prosthesis can provide partial ambulation.

Soft-tissue releases, supracondylar femoral extension osteotomies, and serial casting or amputation may be chosen for limb deformities.

Image Sources
Classification images adapted from Renshaw TS: Sacral agenesis: a classification in review of 23 cases, J Bone Joint Surg 60A:373, 1978
Clinical photograph from of Sacral Agenesis Phillips WA, Cooperman DR, Lindquist TC, et al: Orthopaedic management of lumbosacral agenesis: long-term follow-up, J Bone Joint Surg 64A:1282, 1982.

Related

Spread the Knowledge
15
Shares
 
15
Shares
312   

Filed Under: Spine

About Dr Arun Pal Singh

Arun Pal Singh is an orthopedic and trauma surgeon, founder and chief editor of this website. He works in Kanwar Bone and Spine Clinic, Dasuya, Hoshiarpur, Punjab.

This website is an effort to educate and support people and medical personnel on orthopedic issues and musculoskeletal health.

You can follow him on Facebook, Linkedin and Twitter

Primary Sidebar

Browse Articles

Other View of Mallet Finger Deformity In Index Finger

Mallet Finger Injury Presentation and Treatment

Mallet finger is a finger deformity caused by disruption of the  extensor tendon mechanism distal to the distal interphalangeal joint caused by a bony or tendon injury It is a common injury and occurs as a workplace injury or in sports. It commonly occurs in young to middle-aged males. It is also seen in older […]

Cobb Angle

Cobb Angle – Measurement, Significance and Limitations

Cobb angle is used to measure spinal deformity. The original Cobb angle was used to measure lateral curve severity in scoliosis but also has subsequently been adapted to classify deformity in kyphosis. For evaluation of curves in scoliosis, an anteroposterior radiograph is used. Scolioisis is defined as Cobb angle more than 10 degrees. Relevant Terms […]

tillaux fracture

Ankle Fractures and Dislocations Injuries

Ankle fractures are actually groups fractures involving different parts of the region – the distal tibia, distal fibula, talus, and calcaneus. More often they are referred to fractures involving malleoli, distal tibia, and fibula. But ankle fractures also include the fractures of talus and calcaneum along with above-mentioned injuries. The group also includes fracture pattern […]

nail anatomy

Nail Anatomy and Funtions

The nail is an integral component of the digital tip. It is a unique hardened structure formed by keratinized squamous cells. Nail functions to protect the fingertip and provides a counterforce to tactile sensation and for aiding in the grip formed by fingertips [ as in pinching]. It is also involved in temperature control [thermoregulationion] which […]

Cubital Fossa Location

Cubital Fossa or Antecubital Fossa Anatomy

Cubital fossa is a triangular depression on the anterior aspect of the elbow marked by the flexion crease of the elbow. it contains passage of vital structures and the landmark anatomy is used in clinical measurements.

womac physical function

WOMAC Index

WOMAC index or  Western Ontario and McMaster Universities Osteoarthritic Index is used to assess the course of disease or response to treatment in patients with knee or hip osteoarthritis. Initially developed in 1982, the WOMAC has undergone multiple revisions. What Does WOMAC  Measure? WOMAC measures of three subscales on a scale of 0-4.  [None – […]

Intraarticular fractures - fracture of tibial plateau

Intraarticular Fractures Principles and Management

Intraarticular fractures are the fractures where the fracture line crosses into the surface of a joint resulting in some degree of cartilage damage. The fractures can vary from hairline fractures to displaced fractures. Intraarticular fractures ideally should be reduced anatomically and fixed securely so that early joint movement can be allowed. Where this cannot be […]

© Copyright: BoneAndSpine.com
Manage Cookie Consent
The site uses cookies. Please accept cookies for a better visiting experience.
Functional Always active
The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network.
Preferences
The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user.
Statistics
The technical storage or access that is used exclusively for statistical purposes. The technical storage or access that is used exclusively for anonymous statistical purposes. Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you.
Marketing
The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes.
Manage options Manage services Manage vendors Read more about these purposes
View preferences
{title} {title} {title}
 

Loading Comments...