Wednesday, September 22, 2021


Blog Post: Bertolotti’s Syndrome                                                                                           9-22-2021


What is Bertolotti’s Syndrome?

Bertolotti’s Syndrome involves the lowest vertebra in the back; the one just above the sacrum, called the L5 vertebra. 

Basically, Bertolotti’s Syndrome is an abnormal development of the L5 vertebra, which occurred in utero.  Normally the L5 vertebra is completely mobile (with a normal disc) and whose transverse processes do NOT touch the sacrum (the vertebra just below L5).  In Bertolotti’s the L5 transverse processes can articulate or connect to the sacrum, on one or both sides.

On the below radiograph of the pelvis, the enlarged transverse processes are outlined in blue.







Below, the red lines demonstrate the abnormal articulation between the Bertolotti’s and the sacrum, which is the area which is causing pain.

Are there different types?

In Type 1 there is very little articulation between the L5 transverse processes and the sacrum. 

In Type 2, one or both sides, the articulation is larger and the L5-S1 disc space is slightly narrower than normal.  This is due to this motion segment never having moved normally, so a narrow disc typically develops.

In Type 3 there is an actual bony bridge between the L5 transverse process(es) and the sacrum.  In this type there is a very narrow L5-S1 disc space.



Do all Bertolotti’s cause pain?

The answer is “no”.  Type 1 infrequently have symptoms, and typically do not need much treatment (nonsurgical or surgical). This is because there is not much of a Bertolotti’s so motion at L5-S1 is much more normal.  In addition the larger the actual bony connection on one or both sides (type 3 and 4), the less symptoms are typically present as there is very little motion at the L5-S1 motion segment.

Hence, the type which have the most symptoms are the Type 2.  The reason is there are moderately sized L5-S1 discs, so there is some motion at the L5-S1 motion segment.  This motion can cause pain at the abnormal L5-S1 Bertolotti’s deformity as this connection is stiffer, and the bone of the Bertolotti’s can cause pain, much like a stress fracture.

Where is pain associated with Bertolotti’s?

Most pain with Bertolotti’s is in midline in the low back.

How do you treat Bertolotti’s pain?

Essentially, you start treatment with the same regimen as you would if it were not present: Physiotherapy, over-the-counter analgesic medications, and activity modification is usually the first level of treatment?

What happens if pain persists despite the above-mentioned therapies?

The next step is to obtain advanced imaging, which can be MRI or CT scan.  These imaging modalities can help rule out other causes of low back pain, which can create pain in the same location as Bertolotti’s.  A CT scan can beautifully identify the 3-d structure of a Bertolotti’s, and a 3-d reconstruction of the CT can be very helpful in diagnoses and treatment.

Are there any additional interventions which may help with the diagnosis and/or treatment of Bertolotti’s?

Yes there is……and it involves an injection into the area of the Bertolotti’s under radiographic localization.  The injection usually consists of a steroid and some local anesthetic, so if the injection is at the pain generator (the Bertolotti’s) then the patient should get some temporary relief with the local anesthetic component of the injection, and the steroid may provide some longer lasting relief.

So which patients go to surgery?

The pain has to be persistent and nonsurgical management (physiotherapy, over-the-counter analgesics, and activity modification) have not adequately relieved the back pain (to the patients’ satisfaction), AND has to have had some pain relief from the injection (even if only short-term, only hours of pain relief).

What is “surgery” for Bertolotti’s?

Usually the surgical procedure for Bertolotti’s is resection of the transverse process of L5 (one or both) to fully mobilize the L5-S1 vertebral motion segment.  This is done through a one or two-incision approach in an open (regular incision) or minimally-invasive method (through tube system).

However, if there are large articulations between L5 and S1 and the disc at L5-S1 is very narrow, then a definitive posterior spinal fusion can be a better procedure to mitigate low back pain.

The below radiograph is the patient after surgery.  Notice the absence of the large transverse process/Bertolotti’s.

How effective is Bertolotti’s excision in terms of pain relief?

There can be multiple sources of low back pain.  Because of this, the use of preoperative injections can better assure the pain generator is the Bertolotti’s, and not another anatomic structure.  In general, resection of the Bertolotti’s can typically provide excellent pain relief, as long as the work-up is thorough and complete.

Are there any activity restrictions after surgery?

Short-term yes, long-term no.  After recovery from the surgery, physiotherapy can be started with gradual resumption of athletic activity.

Can the Bertolotti’s come back? Will the bone grow back?


Sunday, September 12, 2021


Blog Post on the latest, hot-off-the-presses publication on Vertebral Body Tethering:


Some important points of this paper:

1.     1.  Surgeries done 2011-2015, prior to FDA approval

2.     2.  FDA primarily interested in device safety, secondarily on efficacy

3.    3.   Inclusion criteria:

a.      Only include Type 1A and 1B curve patterns, which means only main thoracic curves.

b.      There were NO curve patterns with structural proximal thoracic or lumbar curves, and no lumbar curves which deviated from midline (1C curve patterns)

c.      Risser grade 0-4 (median grade 0, 96% were </= 2) and a Sanders </= 5 (median 3).  There was no Sanders grade reported for 20 patients (35% of cohort)

4.    4.   Shoulder balance (no definition in Methods): 54% unlevel  preop and 25% at latest follow up

5.     5.  Follow-up: a minimum of 2 years, mean 55.2 +/-12.5 months.  Though the mean Risser sign at last follow-up was 4.2 +/- 0.9.  Sander Score at last follow-up was 7.5 +/- 0.9

6.      6. Results

a.      Mean age at surgery 12.4 years +/- 1.3 years

b.      49 female; 8 male

c.      Preop MT curve: mean 40.4 degrees +/- 6.8 degrees

d.      Last MT curve: mean 18.7 degrees +/- 13.4 degrees

7.    7.  No neurological complications

8.      8. Thoracic rotation

a.      Preop: 13.6 degrees +/- 3.9 degrees

b.      Postop: 8.6 degrees +/- 4.9 degrees

9.     9. Reoperation rate: 12.3%

a.      5 had tether release for overcorrection

b.      2 had tether extension

c.      1 conversion to PSF



The data is not presented in a granular fashion, but if you assume a normal statistical distribution of their 57 patients:


Standard Deviation

% distribution of patients

Preoperative Main Thoracic Curve Magnitude (in degrees)

# of patients

Last Follow-up Main Thoracic Curve Magnitude (in degrees)





-18 to -7





-6 to +5





















 After backwards-engineering the data (which may not be accurate), 68% of patients had curves 33-47 degrees.  Only 15% of patients had a curve 48+ degrees.



So, based on this paper who MAY be a candidate for a VBT procedure?

Idiopathic Scoliosis

Type 1A and 1B curve patterns (thoracic curves only)

Sanders 2-3-4

Curves 35-55

Rib prominence is less than 20 degrees rotational deformity;

Shoulders level or right shoulder high

Patient and family:

1.      Can accept a 3x reoperation risk vs. posterior spinal fusion (short-term)

2.      Understands risk for a future surgery is unknown and likely to be the same as for a posterior spinal fusion (long-term)

3.      Do not view rib prominence s as a significant part of deformity (VBT only improved 37%)

4.      May not permit detectable difference (to patient and family) in physical activity or function vs. posterior spinal fusion