1. Management of Spinal and Thoracic Deformity in Patients with Myelomeningocele Using Vertical Expandable Prosthetic Titanium Rib
Ajeya P. Joshi, David Limon, R. Zach Garza, Khadija Tayabali, Vishwas Patil, William Koeck, Hope Trevino, James W. Simmons, Robert M. Campbell, Jr.

2. Introduction and Objectives
There are significant challenges to the treatment of spinal deformities associated with myelomeningocele due to the high complication rates of the defect
Vertical Expandable Prosthetic Titanium Rib (VEPTR) is an effective medium-term treatment for the many spinal and thoracic deformities associated with thoracic insufficiency syndrome (TIS)
Objective: Analyze the efficacy of treatment of patients with spinal deformities, associated TIS, and myelomeningocele using VEPTR implants

3. Methods
Retrospective review of 17 patients at a single institution with spinal deformity, associated TIS, and a history of myelomeningocele that received VEPTR treatment
Sitting radiographs measured for coronal and sagittal profile such as Cobb angle, pelvic obliquity, space available for lungs (SAL), thoracic kyphosis, and lumbar lordosis
Charts reviewed for surgical history, assisted ventilation rate (AVR), vital signs, capillary blood gasses (CBG), and complications
All data were collected before and after initial implantation, after a subsequent alteration to the devices used (this does not include device expansion, use of a larger device with growth, etc.), where applicable, and before and after spinal fusion surgery, where applicable

4. Methods Space Available for Lungs (SAL)
Assisted Ventilation Rate (AVR)
To find hemithoracic height, the distance from the superior, medial apex of the hemithorax to the midpoint of the hemidiaphragm was measured bilaterally
The height of the concave hemithorax was divided by the height of the convex hemithorax to give SAL
Perfectly symmetrical hemithoraces would express an SAL of 1
A measure of a patients ventilator dependency status
0 = breathing room air 24 hr/day
1 = use of supplemental O2 (e.g. nasal cannula)
2 = nighttime ventilator use (including CPAP)
3 = occasional daytime ventilator use
4 = fully ventilator dependent

5. Results Demographic Summary # Mean Cobb angle at pre-op
Mean SAL at pre-op
Mean age at VEPTR implant (years)
Average follow-up (years)
7 males
8 females
72.71o
.691
5.5
6.4
Relative to pre-op values:
* = p<.05
** = p<.01
*** = p<.0001
† = possibly due to small sample
size at post #2 * **
*** **
*** †

6. Results
4x4 MM ANOVA of the Effects of Implant Timepoint and Implant Progression on Thoracic Kyphosis
Sum Sq
Mean Sq
NumDF
DenDF
F.value
Pr(>F)
kyphotime 3
imps
kyphotime:imps 6
Further testing revealed that receiving an initial bilateral implant improved TK values (moved them closer to a normal value) relative to patients that initially received
a unilateral implant, but later had a bilateral implant (p<.001).
Additionally, patients with some form of bilateral implant improved over the course of the study, while those with unilateral implants actually worsened.
4x4 MM ANOVA of the Effects of Implant Timepoint and Implant Progression on AVR Value
Sum Sq
Mean Sq
NumDF
DenDF
F.value
Pr(>F)
avrtime 3
imps
avrtime:imps 6
Further testing showed that removal of a bilateral construct to leave only unilateral devices decreased AVR value relative to all other construct progressions. However,
this was somewhat confounded, because all those who kept a unilateral implant throughout the study had an AVR of 0 before their implantation, so it is difficult to
compare relative effects of bilateral versus unilateral implant progressions.

7. Conclusions VEPTR implant associated with Complications
Improved Cobb angle, SAL, pelvic obliquity, lumber, thoracic, and total spine height
Improvement of thoracic kyphosis and lumbar lordosis toward normal values
Advantages to use of bilateral implants in many cases
VEPTR treatment is effective for relief of many structural spinal and thoracic issues associated with myelomeningocele, including improvement of thoracic deformities associated with TIS
VEPTR treatment has minimal effects on the potential for spinal and thoracic growth
Complications
Every patient experienced at least 1 instance of an adverse event, typically manageable
10/17 patients experienced device-related infection
1 patient experienced wound dehiscence
29 device dislodgements in 11 patients
3 patients underwent spinal fusion surgery
There was no difference in the incidence of AEs and infection rates between the different implant progression types
Two deaths occurred, both unrelated to surgery