Evaluation of the effects of laser tissue welding for spina bifida repair
LAS VEGAS (Jan. 23, 2017) — In a study to be presented Saturday, Jan. 28, in the oral concurrent session at 8:45 a.m. PST, at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting™, researchers at Baylor College of Medicine, Houston, Texas; IBEX, Logan, Utah; and Laser Tissue Welding Inc., Houston, Texas collaborated on a study titled, Evaluation of the effects of laser tissue welding on the spinal cord and skin in a 30 day study of simulated spina bifida repair in rabbits.
Spina Bifia is a birth defect where there is incomplete closure of the backbone and membranes around the spinal cord. It affects more than 4,000 children born each year in the U.S. and is associated with hydrocephalus (excessive accumulation of fluid on the brain), developmental delay, lifelong disability and death.
This preliminary study hoped to determine the effects of laser tissue welding on underlying skin and spinal cord tissue. The researchers were interested to see if applying laser energy to coagulate a special albumin compound would damage the underlying skin and/or spinal cord tissue. The researchers plan to use this substance for sealing incision lines in fetal surgical spina bifida repair procedures.
One of the most crucial aspects of a fetal repair is a watertight seal once the repair is complete. "Laser tissue welding is a promising technology that may allow a temporary seal over healing wounds that allows enough time for the regeneration of the skin underneath the albumin layer," explained Michael Belfort, M.D., chairman and professor of obstetrics and gynecology at Baylor College of Medicine, obstetrician/gynecologist-in-chief of Texas Children's Pavilion for Women and one of the researchers for the presentation at the SMFM annual meeting. "By sealing off the incision line with a natural substance that disintegrates over time, we feel that the suture line may heal without developing any leaks which would compromise the repair."
The first step in this experimental process examined whether the heat from the laser (required to activate the liquid albumin and turn it into a solid) would damage the skin or spinal tissue under the skin. Researchers chose a rabbit model because it is an accepted and cost efficient animal model and there was no need to test this in a fetal model until further research is conducted.
"This is just the first step," added Belfort. "Now that we know that the laser energy is unlikely to damage spinal cord tissue we have planned a fetal sheep experiment. We are trying to get funding for this next step."
A copy of the abstract is available at http://www.smfmnewsroom.org and below. For interviews please contact Vicki Bendure at [email protected] 202-374-9259 (cell).
About the Society for Maternal-Fetal Medicine
The Society for Maternal-Fetal Medicine (est. 1977) is the premiere membership organization for obstetricians/gynecologists who have additional formal education and training in maternal-fetal medicine. The society is devoted to reducing high-risk pregnancy complications by sharing expertise through continuing education to its 2,000 members on the latest pregnancy assessment and treatment methods. It also serves as an advocate for improving public policy, and expanding research funding and opportunities for maternal-fetal medicine. The group hosts an annual meeting in which groundbreaking new ideas and research in the area of maternal-fetal medicine are shared and discussed. For more information visit www.smfm.org.
Abstract 83 Evaluation of the effects of laser tissue welding on the spinal cord and skin in a 30 day study of simulated spina bifida repair in rabbits
Michael Belfort¹ , Zhoobin Bateni¹ , Dana M. Haydel¹ , Michael Larson² , Yasmin Wadia³ , Alireza A. Shamshirsaz¹ , William Whitehead¹ ¹Baylor College of Medicine, Houston, TX, ²IBEX, Logan, UT, ³Laser Tissue Welding Inc, Houston, TX
OBJECTIVE: Persistent CSF leak after fetal myelomeningocele repair prevents reversal of hindbrain herniation increasing risk for hydrocephalus. Small skin tears that occur during suturing are difficult to avoid or repair. A reliable, safe method of sealing the skin would be a welcome adjunct to sutures. Laser Tissue Welding (LTW) seals bleeding tissue and stops hemorrhage (Wadia et al 2001). It consists of indocyanine-green tagged human albumin, denatured by 810nm laser light to create a temporary, impermeable layer under which epithelialization can occur. We tested whether LTW causes damage when applied directly over exposed spinal cord and skin in a surgically created spina bifida model.
STUDY DESIGN: 19 New Zealand white rabbits were randomly assigned (9 controls and 10 LTW). Under general anesthesia, via a L2-L5 laminectomy, the dura mater was opened (1cm) to expose the spinal cord and confirm CSF leakage. Controls: para-spinal muscles approximated (interrupted vertical mattress sutures) and subcutaneous tissue/skin closed (interrupted horizontal mattress sutures). LTW group: a 3-4 mm layer LTW solder placed over exposed spinal cord and then activated with laser. The wound was then closed as with controls and 3-4 mm layer LTW solder activated over the skin suture line. All animals were observed for neurological function/CSF leaks postoperatively and then randomly euthanized at 2, 15 or 30 days. The spinal column with overlying skin was fixed in formalin and examined by a dermatopathologist blinded to treatment.
RESULTS: There was no clinical CSF leak in either group. Histology showed thermal damage to epidermis in day 2 skin samples in the LTW group with preservation of the deeper regenerative layers. Epidermal regeneration/reepithelialization was seen at day 15 and more so at day 30. There was an accompanying fibroblast tissue reaction within the dermis progressing from granulation tissue (day 2) to scar (day 30). There was no thermal damage seen on/over the spinal cord and there was no cord tethering/distortion. (Figure)
CONCLUSION: The LTW process created a second degree burn on the skin that healed well. LTW does not appear to damage spinal cord or neural tissue. Fetal sheep studies are planned to test whether LTW can be used to seal the suture line in fetoscopic fetal meningomyelocele repair.