PELVIC OBLIQUITY

Mohahad osman, MD Assist. prof. Zagazig University

Definition of Pelvic Obliquity ( PO)

A- PO is failure of the pelvis to lie in a perfectly horizontal position in the frontal plane; ie; interspinous line is not perpendicular to midline of body provided that legs are parallel to midline of body.

B- 3-D definition : any fixed malalignment bet. Spine & pelvis, in frontal, sagittal, horizontal or all these 3 planes.

CLASSIFICATIONS of PO.

I- Mayer (1936) : 1- Functional / non-structural PO :- present only when pt. stands with knees straight & no lift under foot & disappear on sitting & on recumbency w legs parallel to midline of body - due to LLD. 2- Structural / fixed PO : -persists in all positions & cannot be passively corrected. -Aetiology: a- infrapelvic (hips) b- pelvic c-suprapelvic ( spine) d- combined

II- Dubousset ( 1991) : 1- Regular PO : spine & pelvis in same directions of deformity. 2- Opposite PO : in opposite directions.

Classifications of PO. ( cont.)

INFRA-PELVIC FIXED PO.A- Congenital hip contracture: 1- cong. Abductor contracture 2- cong. Adduction contractureB- neuromuscular hip contractures : abd, add or both.SUPRA-PELVIC FIXED PO.: - in cong. or neuromuscular scoliosis - not in idiopathic scoliosis ( curve not extend to pelvis )

A- locomotor:Interferes w sitting, standing balance & walking.B- 2ry. Deformities : * spinal : L. scoliosis( cause / result) . Increased L. lordosis. * hip : Abd / add contractures . * knee : hyperextension on long side * apparent LLD.C- decubitus ulceration: ischial / G. trochanter on lower side.

DISABILITY & SEQUILAE of PO.

DIAGNOSIS & ASSESSMENT OF PO.

HISTORY

GENERAL EXAM.: * CARDIOPULMONARY FUNCTION * Gait : - short leg limp ( dipping gait) - Trendlenburg gait

EXAM OF DEFORMITY : * inspection * palpation

a- Pelvic obliquity: * Oblique pelvis : interspinous line is not perpendicular to midline of body provided that legs are parallel to midline of body

* functional PO.; present only when pt. stands with knees straight & no lift under foot & disappear on sitting & on recumbency w legs parallel to midline of body

* fixed PO. : persists in all positions & cannot be passively corrected 1- infra-pelvic; overcomed by swining legs to one side or other while recumbent. 2- supra-pelvic; never.

EXAM for FIXED DEFORMITY:

B- Scoliosis: * trunk alignment : plumb line * type of curve * flexibility / rigidity of curve * rotation * neurologic exam. * clinical photographs.

C- Fixed hip def. : abd, add, flexion ,rotation

EXAM for FIXED DEFORMITY ( cont):

ROM : hip. Spine . Knee. Ankle.

NEUROLOGIC EXAM: - Power - specific muscles ( hip / trunk) -sensation

MEASUREMENTS : - PO. - LLD ( app / true) - circumference.

SPECIAL TESTS : - iliotibial band - hip instability.

Ober test

RADIOLOGIC ASSESSMENT

A- Pelvic obliquity : * diagnosis of PO. : - in frontal plane - 3-D * Angle of PO: Osebold , 1982

B- Scoliosis:A- Angle ( Cobb ) B- rotation ( pedicles displac.)C- c rigidity : - side bending - traction - suspensionD- Torso decompensation: OseboldE- Pt. maturation : Risser sign

LORDOSISSPINA BIFIDA2ry changes in hips

CTMRI

A B

C

A- side-bending XRB- suspension XR

C- traction XR

Torso decompensation / trunk list

C- MEASUREMENT of LEG LENGTH-Plain X- ray: scanogram- CT

OTHER INVESTIGATIONS: * cardiopulmonary * Biochemical ; ms dystrophy

TREATMENTTTT of PO is directed to the specific cause

Ttt of functional PO: - by leg length balancing - up to 3 cm LLD ; shoe lift - > 20 cm LLD; orthosis - 3-20 cm LLD; shortening, lengthening or both. * correct bony def. or jt. Contracture 1st.

TTT of infra-pelvic type:

A- cong hip contractures: - early ; stretching / traction and spica casting - neglected ; surgical release & splinting.B- Paralytic hip contractures ; surgical - abd contracture by ; 1- soft tissue release ( prox & distal). 2- STR+ erector spinae transplant or 3- STR+ intertroch. femoral osteotomy ; > 3 y old, severe, 3-D - add contracture ;

TTT of supra-pelvic type

A- Abdominal fascial plastic operationsB- Muscle- tendon transplant operations

C- Spinal surgery.

Spinal surgery :Objective: correction of def. to the point at which pelvis is level & then fusion of spine & pelvis in that corrected position.

Methods :

A- Post. Surgery only; if pelvis can be levelled by passive bending / traction * Harrington sacral bar * Luque * recent segmental instrumentations B- Combined ant. & post . Surgery ; if pelvis can not be levelled by passive bending / traction or deficient post. elements * ant correction& fusion without instrumentation * ant correction& fusion with instrumentation ( Dwyer system).

TTT of combined type

A- correct hip & knee def. 1st then spinal fusion, otherwise spinal def will recur [ Barr, 1950 & Turek, 1984]

B- Beaty [1992]; when PO is moderate & L. scoliosis is fixed , correct scoliosis w instrumentation 1st.

TTT of PO that cannot be corrected by hip / spinal surgery

INDIC.: 1- 2ry osseous hip changes or 2ry arthritic changes in L spine rendering full correction impossible. 2- residual significant fixed PO [ 18 deg]

METHODS: 1- LL realigning to trunk by femoral osteotomy 2- post iliac osteotomy [ Lindseth,1978]; compensating pelvic def. placing isch tuberosities & acetabla in planes perpendicular to long axis of body 3- ischium excision; partial / complete

post iliac osteotomy [ Lindseth,1978];