Special care is taken for women undergoing gynecological surgery procedures at K and B Surgical Center.  Experts in women’s surgical care, along with a dedicated and understanding staff, allow women the benefits of stellar surgical care within a private and caring environment.African American Family Playing Baseball

Pelvic organ prolapse (POP) and urinary incontinence (UI) are common conditions affecting many adult women today.

Pelvic organ prolapse is a defect of a specific vaginal segment characterized by descent of the vagina and associated pelvic organ. Patients have varying degrees of prolapse, and in the most severe cases (complete pelvic organ prolapse), the pelvic organ protrudes completely through the genital hiatus. In such cases of pelvic relaxation, multiple defects are associated in the anterior, lateral, posterior, and apical compartments.  Laparoscopic Surgery is an option for Uterovaginal and Vaginal Prolapse.

Meet our Surgical Gynecology/Urology Team

Dennis Kim, M.D.

Dr. Dennis Kim brings his expertise in the specialties of urinary incontinence, voiding dysfunction, and female and male reconstructive urology to K and B Surgical Center.

A native of Connecticut, Dr. Kim attended the University of Michigan in Ann Arbor, MI graduating with a double major in chemistry and molecular biology. He then movedDR._KIM to California and earned a master’s degree in public health from the UCLA School of Public Health. He received his medical degree from Albany Medical College in Albany, NY where he was elected to the Alpha Omega Alpha Medical Honor Society.

He finished two years of general surgery training and four years of urology training at the Kaiser Foundation Hospital in Los Angeles, CA.

He completed fellowship training at the Cleveland Clinic Foundation Hospital
in Florida sub-specializing in urinary incontinence, voiding dysfunction, and female and male reconstructive urology.

Dr. Kim has authored several peer-reviewed scientific papers and a book chapter on incontinence, voiding dysfunction, and female and male reconstructive urology.


Stacey P. Rosenbaum, M.D.

Dr. Rosenbaum is a board-certified obstetrician/gynecologist.  Her clinical and research interests include the treatment of endometrial abnormalities.

Medical School:
University of Pennsylvania School of Medicine Medical Degree
University of California, Los Angeles
Bachelor of Science, Psychobiology
College Honors Program
Phi Beta Kappa, Summa cum Laude

Residency Training
Kaiser Permanente Southern California
Obstetrics & Gynecology
Resident Chief Administrator

Board Certification
American Board of Obstetrics & Gynecology

Hospital Appointments
Cedars-Sinai Medical Center


Rebecca Nelken, M.D.

Rebecca Nelken, MD, is a pelvic and reconstructive surgeon.  She is board certified in obstetrics and gynecology.

Dr. Nelken’s major areas of research include pelvic organ prolapse, urinary incontinence and medical education. She has published extensively in peer reviewed journals, authored book chapters, abstracts and poster presentations on various subjects related to women’s pelvic health.dr-nelken

In addition to being a member of the American Congress of Obstetrics and Gynecologists, she is a member of the American Urogynecologic Society.  With a commitment to public service, Dr. Nelken volunteers at the Saban Free Clinic, formerly known as the Los Angeles Free Clinic.

After graduating from Columbia College, Columbia University, in New York with a bachelor’s in history/premed, Dr. Nelken went on to earn her medical degree from the Keck  School of Medicine at the University of Southern California (USC).  She went on to perform an internship and residency in obstetrics and gynecology and a fellowship in female pelvic medicine and reconstructive surgery, all at USC.  Throughout her academic career, Dr. Nelken has earned many awards and scholarships.


Ayanna Walden, M.D.walden

Dr. Walden is board certified by the American Board of Obstetrics and Gynecology.  Her clinical interests include preventative medicine, adolescent gynecology, contraception, treatment of abnormal pap smears, and management of fibroids, hysteroscopy, laparoscopy and minimally invasive surgery. She also volunteers at LA Free Clinic and has done several medical missions to underserved countries.

Dr. Walden earned her Bachelor of Science degree in Biology from Providence College and another degree in Biochemistry from Florida State University. She received her medical degree from the University Of Florida College Of Medicine. She then performed her residency training at Cedars Sinai Medical Center.


Christine Collins, M.D.Dr. Christine Collins is an attending physician  at Cedars-Sinai Medical Center  and has been in private practice since 1996.   She gcollinsraduated from USC School of Medicine and did her residency training at Cedars Sinai Medical Center.  During medical school, Dr. Collins won the prestigious ARCS (Achievement Reward for College Scientists) Scholarship and graduated as a Dean’s Scholar. She is board certified by the American Board of Obstetrics and Gynecology and is a fellow of the American Congress of Obstetrics and Gynecology.

Dr. Collins focuses on  nutrition and uses an integrative medical approach in  caring for her patients.  Over the past five years, she has expanded her knowledge base and is board certified in Anti-aging and Regenerative Medicine.   Her main interest is treating women of all ages using an integrative and holistic approach.


Ann Hofstadter, M.D.

Dr. Ann Hofstadter has been in private practice since 1996. She is board certified by the American Board of Obstetrics andhofstadter Gynecology and is a fellow in the American Congress of Obstetricians and Gynecologists. She is an Attending Physician at Cedars Sinai Medical Center. Dr. Hofstadter’s areas of interest include preventative medicine, adolescent gynecology, the treatment of abnormal pap smears and managing peri-menopausal and menopausal symptoms.  She is currently developing a program to address sexual drive and weight management in women using a multidisciplinary approach, combining western medicine, traditional eastern medicine, psychotherapy and hypnosis.

Dr. Hofstadter received her Bachelor of Science and Bachelor of Arts degrees from Stanford University. She received her medical degree from Baylor College of Medicine. She did her residency training at Cedars-Sinai Medical Center and served as Administrative Chief Resident.


Jason Rothbart, M.D.

Dr. Jason Rothbart offers a comprehensive practice of Obstetrics, Gynecology and initial workup and treatment for Infertility. Born and raised in West Los Angeles, Dr. Rothbart is proud to be home and serving this community. His practice is conveniently located in Century City, between Santa Monica and Beverly Hills. rothbart

Dr. Rothbart offers a gentle, compassionate and individualized experience for his patients. His pride in showing each patient genuine care, patience and respect instantly sets him apart. He is a rare breed of physician who truly loves what he does and it is apparent in the kind of medicine he practices.

Extensively trained in Chicago and at the USC Los Angeles County Medical Center, Dr. Rothbart’s wide breadth of knowledge, expertise and surgical skill complements his bedside manner to give his patients a complete and comforting experience.


Sonia Rebeles, M.D.

Sonia Rebeles, M.D., F.A.C.O.G., is Board Certified in Obstetrics and Gynecology, now practicing in Beverly Hills, CA. Her area of expertise is in minimally invasive benign gynecologic surgery including robot-assisted (daVinci) surgery and single site surgery.

Dr. Rebeles received her Bachelor of Arts degree from Stanford University in Human Biology and her medical degree from the University of Texas Health Science Center at San Antonio. She completed residency training at Texas Tech University Health Sciences Center at El Paso where she subsequently served as an Assistant Professor in Obstetrics and Gynecology and Director of the Minimally Invasive Surgical Skills Laboratory.rebeles

In Seattle, WA, she obtained additional post-residency fellowship training in minimally invasive surgery, where she refined both traditional laparoscopic and robot-assisted (daVinci) surgical techniques using some of the earliest models of robot-assisted surgery. She is one of few female surgical proctors of robotic surgery and has taught many physicians the fundamentals of minimally invasive gynecologic surgery throughout her career.

Dr. Rebeles is a Fellow of the American Congress of Obstetricians and Gynecologists (FACOG), and is an active member of the Alpha Omega Alpha Honor Medical Society, and the American Association of Gynecologic Laparoscopists. Her interests include irregular, heavy or painful menstrual bleeding, fibroids, endometriosis, pelvic pain, and urinary incontinence.

Using a combination of compassionate and empathetic care, evidence-based medicine, sound knowledge of pelvic anatomy, and the incorporation of state-of-the art surgical technology, Dr. Rebeles is committed to offering women innovative treatment options for multiple gynecologic problems.