@elizabeth9 Hello Elizabeth and welcome to Connect! I am a Mayo spine surgery patient for cervical stenosis. In doing a quick search about Berlotti's syndrome (which is an abnormal formation of vertebrae that join the lumbar spine and pelvis), I came up with this article describing the condition and treatment.
https://www.ncbi.nlm.nih.gov/books/NBK585032/
I wanted to see the names of specialists who would specialize in this condition, so I scanned down to look at the literature that is credited at the end, and I saw a name I recognized... my neurosurgeon at Mayo in Rochester, Dr. Jeremy Fogelson. I looked up his literature on surgical treatment of Berlotti's and both he and Laura Waksdahl (who was my surgical nurse) are authors.

Operative Treatment of Bertolotti Syndrome: Resection Versus Fusion
Anthony L Mikula 1 , Nikita Lakomkin 2 , Ryan C Ransom 2 , Patrick M Flanigan 2 , Laura A Waksdahl 2 , Zach Pennington 2 , Manish S Sharma 3 , Benjamin D Elder 2 , Jeremy L Fogelson 2
https://pubmed.ncbi.nlm.nih.gov/35717016/
Dr. Fogelson is one of Mayo's best surgeons and is a spine deformity expert who trained in neurosurgery at Mayo, also did an orthopedic spine deformity fellowship, and teaches in the Mayo neurosurgery program. He is a compassionate doctor as well as an excellent surgeon. I highly recommend him.
https://www.mayoclinic.org/biographies/fogelson-jeremy-l-m-d/bio-20055624
If you wanted to seek care at Mayo, you may use this link to request an appointment.
http://mayocl.in/1mtmR63
Here is a video where Dr. Fogelson is speaking so you can "meet" him.

May I answer any questions for you about my care from Dr. Fogelson at Mayo Clinic?