Part 1. A pictorial essay

Wolfgang.G.H. Schmitt-Buxbaum

10 years ago Billet and Schmitt (2) wrote a paper on the subject. Since then we observed more cases, so we obtained the largest casuistics concerning osseous bridges between lumbar transverse processes. Meanwhile we have learnt more about the problem. Lumbar transverse processes lead to many misunderstandings in literature. -

Our interest in transverse processes pathology began with the following two cases:

1a. 3D surface reconstruction of a CT scan of the lumbar spine. -

If you think this would be

- a congenital malformation,

- a lack of segmentation of the lumbar segments,

- a "Sacralization" of the lumbar spine,

you`re wrong! This case collection is written for you; you should carfully

study it. We would like you to listen to our points and we will listen to


The diagnose is "traumatic osseous bridge between lumbar transverse processes".


1b. X-ray image of the lumbar spine (anterior-posterior projection).

If you think that it is a

- congenital alteration,

- rudimentary ribs in the lumbar spine,

- an imitation of thoracic spine created by the lumbar spine,

- "lumbar ribs"

you're wrong!

You should carefully study this presentation!

The good clinician says: No diagnosis without the patient’s history and

without the clinical picture!

That's true, but here is one of the few exceptions: The clinical picture

takes you sometimes onto the wrong track. - In case 1a however, clinical history with a lumbar damage was the cast iron proof for the diagnosis.

The situation was more difficult in case 1b: The patient pretended, he had had no trauma before. His history was misleading.

Carefully repeated anamnesis however revealed a trauma 5 years before. So we assume old transverse process fractures L1-3 left. Bone formations are dislocated caudally from the amputated corresponding transverse processes. They fit together in size and shape for a complete transverse process. Our fist assumption of "lumbar ribs" does not explain the dislocation of fragments and the corresponding diminution of transverse process stumps.

(Compare to the osseous bridges (fig 5 -14), which is another unusual form of transverse process fracture healing).

Similar to the osseous bridge this condition is often misinterpreted as a congenital malformation.


2.Other cases misunderstood as "lumbar ribs":

Bild 2a (click to enlarge, move with blue bar, your diagnosis? See legend below.)

Bild 2b (click to enlarge)

In all cases 2a-d, the diagnosis is "lumbar transverse processes fragments" that were inconsistently consolidated with their basis".

The correct diagnosis:
Processus fracture healed with dislocation.

You may use the description:
Non-association fragments.
I would not use the term "Pseudarthrosis" because the dislocation of fragments excides 0,5 cm.

2a. It looks like an ordinary fracture of the right L3 lumbar transverse processus.
Surprisingly, the accident (with proven fracture) took place 6 months earlier. We find no consolidation. Probably no consolidation will occur.

2b. Lumbar transverse processes fracture 14 years ago: The former circumscribed destruction in right lumbar transverse processes L2 and L4 now shows smooth contours. The consolidation of lumbar transverse processus L3 with a low contour irregularity and remarkable thickening.

Image 2c (click to enlarge, move with blue bar, your diagnosis? See legend below.)

Image 2d (click to enlarge)

2c. 9 month after car-accident we see a pronounced unstable fracture of lumbar transverse processus L2: The right lumbar transverse processes L3 and 4 are shortened, the fragments have a smooth contour and are still dislocated; no signs of consolidation.

2d. Fracture of lumbar transverse processes 21 years earlier: Healed with a plump and stumpy deformation of L3, and a hole formation. (Hole formation is an interesting phenomenon which implies a coexistence of regional surplus and lack of bone.)

3. Common pathology?

3a (click to enlarge for picture, move with blue bar, your diagnosis? See legend below.)

3b (click to enlarge for picture)

The last 4 cases were rare findings. In contrast the following patients 3a, 3b and 3d show frequent, common pathology. We doubt whether we should show you such "every day"- observations. But the routine is instructive to highlight the special (3c, 5 - 14).

3a. 7 ½ years before: motorcycle accident with lumbar transverse processes fractures L2-4 right:

Unlike the above cases (2 a-d) there is a complete consolidation. Step deformity with dislocation in caudal direction.

3b. Status after transverse processes fractures L 3 and 4 (right) years before: Deformation of L3 with shortening, congestion and rolling contours.


Image 3c (click to enlarge, move with blue bar, your diagnosis? See legend below.)

Image 3d (click to enlarge)

3c. A rare case. 44-year-old man (St. Hu.). X-ray 11 years after transverse processes fractures L2 and L3 (left). Lumbar transverse processus L3 has increased in volume. Both processes L2 and L3 show exostoses which seem to have contact with each other (Pseudarthrosis). This case turns out to be a case of special interest: In two neighbouring fractures not only the fractures heal, but additionally a connection is formed between the two separate fractures. It is not a complete fusion but a pseudarthrosis. (Fusions in form of stable bridges will be shown later).

This bridge (with or without articulation) is a "new dimension of fracture healing" and has a functional result.

Remember the bridge begins to lock two related bone sections and minimises the original mobility. An interlock does not take place in the facet joints (nor in the intervertebral space), the lock is located beyond (laterally) the classical articular connection and reduces movement or eliminates it. The clinical importance may be low. But this fact is useful for diagnosis.

Such a restriction in motion influences the aging process. The narrowed spinal connection protects against further degeneration. This protection happens at the cost of the neighbouring spinal joints, where increasing degeneration may take place (7).

3d. An everyday case : Formation of Spondylophyts. – Here we have clear ideas on nature’s intent: The ground plate will be broadened to diminish the pressure. Excessive mobility will be restricted.

4. An excursion to an other skeletal regions

An excursion to an other skeletal regions, and conditions: Fracture healing with a surplus of the bone is unfortunately not unusual.

4a. Comminution fracture in the lateral clavicle: Strong haematoma, probably dissemination of the bone and connective tissue in the comminution zone. - Conservative therapy. Probably these are conditions for the observed extensive bone formation.

4b. Total Endoprosthesis of the right hip joint: Lack of mobilization because of neurological disorder. Excessive bone formation within a year (picture right). The conditions are not completely clear. Such a follow up is frightening for every surgeon.


Image 4c (click to enlarge, move with blue bar, your diagnosis? See legend below.)

Image 4d (click to enlarge)

Image 4e (click to enlarge)

4c. Comminution fracture of the pelvis (posterior column), Osteosynthesis, infection: Risks for the marked bone-formation around the right hip joint, restricting the hip joint mobility.

4d. Gastrectomy because of stomach cancer. After 2 years no evidence of tumor progression but a long, hard resistance under the scar: Bone formation in a scar. – Histologic examinations done in similar cases revealed plain bone tissue.

4e. Osteosynthesis because of fracture of femoral diaphysis: Professional horse rider for many years and horse trainer. An accidental finding was this rider-bone in the adductor muscles close to the Tuber ischiadicum. Multiple micro-injuries seem the cause for such ectopic bone formations.

4f. Healed abscesses following injections into the gluteal region:The link above bringes you to the chapter "Artefakte II" and to another case of gluteal abszesses.

The majority are not just "calcification", but a real bone-tissue. A transformation of cells was generated by infection.

5. In the following (fig.5-15) we hope to show you an extraordinary scope.

5a (click to enlarge for picture)

5b (click to enlarge for picture)

In the following (fig.5-15) we hope to show you an extraordinary scope.

One of the messages will be: When degenerative changes are present, bridges between the lumbar transverse processes prove that they are acquired before formation of a bridge.

Particular attention was paid to previous traumata and to conditions which could explain activated bone formation or disposition to bleeding.

In no patients were the following conditions found: Diabetes, Psoriasis, pustulous skin lesions, Multiple exostosis, Morbus Bechterew, Hemorrhagic Diathesis.

5a. 34 yr old man (Hi.Wi.). Automobile accident with fractures in the middle of transverse process L1-4 left.

5b. The same case 2 yrs after the trauma: Continuous bone formation between the transverse process L 2 - 3 on the left. Slight narrowing of the disc. Very slight scoliosis convex to the pathological side. Bar-like deformity of the transverse processes L1 and 4 left.

Like transverse process fractures in acute trauma, osseous bridging in the post-traumatic stage is only one aspect of a complex traumatisation, including the soft tissue of the retroperitoneum, thorax and pelvis.

One of the few cases of proven traumatic etiology. In literature we find 10 proven cases and add 2.

There are remarkable similarities between cases of proven traumatic origin and cases of unknown origin.

6. 48 yr old man (Bl.Jo.), fell from roof 5 yrs ago

Image 6 (click to enlarge, move with blue bar, your diagnosis? See legend below.)

48 yr old man (Bl.Jo.), fell from roof 5 yrs ago. Osseous bridge between the middle of transverse processes L3 and 4 left. Pseudarthrosis somewhat underestimated on this 3D-reconstruction in comparison to the x.rays. Marked restriction in motion.

Were the intervertebral junction blocked congenitally, the presence of disc degeneration and osteoarthric changes could not be explained.

CT reveals that some of what could be considered benign lesions are actually complex spine fractures or complex soft tissue lesions. Therefore CT helps to diminish the risk of overlooking potentially serious injuries of spine, pelvis and thorax and of soft tissues (retroperitoneum, pleurae, lungs).

7. 46 yr old man (Pi.Ac.), hit by a car

7a (click to enlarge for picture)

7b (click to enlarge for picture)

7a. 46 yr old man (Pi.Ac.), hit by a car while helping in an emergency 2 years ago. Proven fractures of transverse process L2,3 right, but no other fractures, no associated anomalies. Actually examinated for an insurance. The osseous bridge between transverse processes looks similar to the case shown in fig. 6, but the lesion is in a different segment and on the other side. The pseudarthrosis is more prominent. The Spondylosis deformans was present at time of the accident and could not have developed in this mostly bent intervertebral junction.

7b Same case. Other proiections.

8. 58 yr old man (Fi.Fr.), fell from a 6 foot ladder

8. (click to enlarge for picture)

58 yr old man (Fi.Fr.), fell from a 6 foot ladder 8 yrs ago.

Osseous bridge between the middle of transverse processes L3 and 4. Pseudarthrosis. Typical form of commonly found H-shape. Slight deformation of transverse process L2 right. Degenerative intervertebral changes a sign of acquired bending.

9. Farmer (He.Wi.), 62 yrs old, fell from a granary

9. (click to enlarge for picture)

Farmer (He.Wi.), 62 yrs old, fell from a granary 10 yrs ago. Pseudarthrotic osseous bridge with small junction between the transverse processes L2 and 3 left. Spondylosis deformans in all segments.

10. One of the only 4 women in our 18 own observations

10a (click to enlarge for picture)

10b (click to enlarge for picture)

10c (click to enlarge for picture)

One of the only 4 women in our 18 own observations. One of the only two own observations in which the traumatic cause is proved by follow up.

10a. The 22 yr old woman (Sc.Si.) suffered from a severe car accident 2 years ago with fractures of left pelvis, left femur, transverse processes L2-4 right, and paralysis of peroneal nerve. Osseous bridge in the middle of three still recognizable transverse processes, with tough pseudarthrosis.

She is the youngest patient of all. There is a complete lack of cases observed in children, an argument against the congenital theory.

10b. Other projections of 3D-reconstruction. The bridge locks lumbar mobility.

10c. Reconstruction of coronar slices.

11. 77 yr old man (Ko.Er.), severe trauma

11a (click to enlarge for picture)

11b (click to enlarge for picture)

11c (click to enlarge for picture)

11a-c. 77 yr old man (Ko.Er.), severe trauma 20 y ago. Irregular brige between L4-5 and os ileum. Marked Osteochondrosis in the segments with now reduced mobility. This must have been acquired before the accident. The 3D-reconstruction is calculated from data of a single-slice-CT. Today it can be performed in an even better quality.

12. 52 yr old man (Ku.He.)

52 yr old man (Ku.He.). 25 years ago: Pelvic fracture anterior on both sides, fracture of massa lateralis of the left sacral bone and lumbar transverse processus L4 (left). X-rays at time of the accident were not available.

- Fractures consolidated with deformation. Crude Pseudarthrosis between lumbar transverse processes and an exostosis originating from upper sacral bone.

13. 52 yr old man (We.Dk.)

52 yr old man (We.Dk.). Car accident 16 years before. No x-ray. Probably fractures of transverse processes L 1-4 left. Post-traumatic bridge (h-shape in the classification of Billet (2)) between lumbar transverse processes L 1-2 left.

14. 38 yr old man (Ef. Jo.)

38 yr old man (Ef. Jo.). Trauma 12 years before. Post-traumatic remarkable bony bridge between lumbar transverse processes L4 and L5 and the deformed, formerly "shattered" sacro-iliacal region left.

You find more case reports in our first paper (2).

15. Drawings of some marked own cases

15a (click to enlarge for picture)

15b (click to enlarge for picture)

15c (click to enlarge for picture)

15a. Drawings of some marked own cases. Some were already shown above.

a-b. fig.5; c. fig.9; d. (Re.Eu.); e. fig.8; f. fig.14;

15b. The different shapes of lumbar transverse processes bridges according to Billet (2).

Among 59 cases the majority (27 cases) was classified as H- or h-shape. 10 K-shapes and 8 Z-shapes were found.

The O-shape - 9 of 59 cases - seemed to correlate with the supposed congenital origin, but there were exceptions with clear traumatic genesis.

15c. Drawings of bridges between lumbar transverse processes from literature. An other pictorial overview is shown by Yoslow. Aspects reviewed give a clear picture of age, side, form, size, bilaterality and clinical significance, as well as the role of CT in diagnostics, with special regard to 3D reconstructions.

16. Excursion to a different region of the skeleton

16a (click to enlarge for picture)

16b (click to enlarge for picture)

16a. Excursion to a different region of the skeleton: Avulsion fracture of the bony pelvis. In this region of skeleton nobody is surprised that such dislocated parts heal without contact of the fragments.

16b. Similar fracture. Healing with marked deformity but bony consolidation.

17. 3D reconstruction

17a (click to enlarge for picture)

17b (click to enlarge for picture)

17a + b. 3D reconstruction. Healing of a fracture in the left os sacrum with a huge

bony exostosis directed caudal - lateral. The newly formed bone partly follows the sacrospinous ligament.

18. Rib fractures

Also rib fractures can consolidate with bony bridges and form Pseudarthroses.

19. 62 yr old diabetic male

Forestiers disease. Bone formation following the anterior ligament.

20. Bild NEU 55a

Other case of
Morbus Forestier.
Digital radiogaph.

21. Bild NEU

20a. Same case.
Computerized Tomography
in a saggital plane

All cases shown above offered no evidence for a metabolic disorder or evidence for an inflammatory disease (Psoriasis, Bechterev). But this possibility should be kept in mind. -

Here is a 62 year old diabetic male with Forestier's disease . Abounding bony tissue bonds the cervical vertebrae. Patient’s history revealed no trauma.

Diese von dem Arzt Forestier aus Aix les Bains beschriebene "Hyperostosis ankylosans vertebralis senilis" tritt vorwiegend bei älteren Menschen,  bei Männern und bei Diabetes mellitus auf. Die  Knochenneubildung respektiert Nerven und Gefäße und verursacht daher kaum Schmerzen.