Introduction: Spinal deformities (scoliosis, kyphosis or kyphoscoliosis) in children under 10 years of age result from congenital, neuromuscular and idiopathic etiologies. The progression of the deformity is affected by its nature, location and age of onset. Spinal arthrodesis is the procedure of choice in patients with progressive deformities. The use of instrumentation facilitates curve correction and arthrodesis rates. Pediatric spinal surgery is technically demanding, and is still considered controversial. The advent of reduced size spinal instrumentation allowed surgeons to expand their use to pediatric patients. The use of spinal instrumentation in children with various spinal deformities has not been well documented.

Objective: To assess the safety and efficacy of spinal arthrodesis in young patients with progressive spinal deformities.

Patients and Methods: We retrospectively reviewed the medical charts and radiographs of 25 patients younger than 10 years of age who underwent corrective surgery for various spinal deformities. Radiographic outcome, fusion rates and complication were compared between instrumented and non instrumented patients.

Results: At two years of follow up instrumented corrective procedures resulted in superior correction compared to non-instrumented patients and in solid arthrodesis in all. Complications were infrequent.

Conclusions: The use of reduced size spinal instrumentation in young patients with progressive spinal deformities is safe and effective. Curve correction, length of bracing and fusion rates are all in favour of instrumentation, wile complication rates are acceptable. The use of spinal instrumentation in young patients requires expertise and patience.

Introduction: Spinal fusion has become a popular surgical technique. Problems of fusion failure or pseudo-arthrosis as well as bone graft donor site complications are common. Ex vivo gene therapy using mesenchymal stem cells (MSCs) and bone morphogenetic protein (BMP) genes can provide a local supply of precursor cells and a supra-physiological dose of osteoinductive molecules that may promote bone formation and lead to spinal fusion.

Methods: Thirty 6–7 weeks old C3H/HeN immune-competent female mice received an injection of 2x10⁶ genetically engineered MSCs to the para-vertebral muscle of the lumbar spine (L2-L6) under manual palpation. Ten animals served as negative control group and 20 animals constituted the experimental group.

Bone formation in the para spinal region of the injected animals was evaluated by histology staining. Quantitative analysis of the fusion mass was monitored by micro computerized tomography (μCT).

Results: At 1, 2, 4 and 8 weeks post injection. Bone formation was extensive, as soon as the 1^st week post injection, in the area adjacent to and adhering to the posterior elements of the spine in all the study animals. None of the control animals, in which hBMP-2 was inhibited, showed any new bone formation.

Discussion: Exogenously regulated expression of the hBMP-2 enabled us to regulate bone formation in vivo, using genetically engineered MSC system. The effect of hBMP-2 in inducing bone formation was monitored in real time, non-invasive and quantitative system that enabled us to better understand the biological process during bone regeneration and repair. Our data demonstrate a regulated and monitored system for inducing bone for spinal fusion. We conclude that controlled gene therapy for spinal fusion can be achieved using Tet-regulated hBMP-2 gene and MCSs.

Purpose: To describe the role of osteotomies in rigid spinal deformities

Patients and Methods: One hundred fifty six patients with spinal deformities undergoing surgery between March 1998 and August 2005 were identified from our spine registry. Our study cohort included 23 cases where osteotomies were performed for correction.

Corrective osteotomies were one of: 1) wedge osteotomy convex based; 2) wedge osteotomy dorsally based; 3) complex wedge or eggshell osteotomy for combined frontal and sagittal plane deformity. Patient’s demographics, type of deformity, underlying conditions, operative results, complications, and need for secondary procedures were documented.

Results: Twenty three patients (15%) with rigid curves underwent osteotomies as part of their corrective surgery. Mean age in this cohort was 11.3 years (2–26), 35% were males, 65% females. In 17 of the patients the main deformity was scoliosis, in 5 – kyphosis and in – 1 lordosis. MMC was the leading underlying condition in 4 cases, followed by VACTER syndrome (2), congenital myopathy (2), arthrogryposis and pterygium (2), Neuro-blastoma (1) and other congenital conditions. Operative results were satisfactory in terms of cosmetics, alignment and function. In 3 cases (13%) complications were encountered, with 2 infections requiring debridement, (one requiring hardware removal) and 1 Neurofibromatosis patient undergoing her 8^th surgical procedure, developing an intraoperative partial neurological injury with nearly full recovery.

Conclusions: Osteotomies are an important part of surgery in rigid spinal deformities. These deformities occur frequently in syndromatic children making peri-operative treatment more complex. Osteotomies facilitate better outcome in terms of correction, sagittal and coronal balance and cosmetics. These procedures are highly demanding technically. However, it is our opinion that adequate correction of rigid deformity with the benefit of spinal column shortening by way of osteotomy, is protective from significant neurological traction injuries that otherwise may occur.

Combined anterior/posterior scoliosis surgery is the mainstay of scoliosis surgery in large curves with Cobb angle more than 65°, in stiff curves that correct to above 40° only on the pre-operative bending films and in Steersman’s kyphosis greater than 90°. The combined anterior/posterior scoliosis surgery allows better correction of the curve, saving motion segments in the spine and eliminating the occurrence of the crankshaft phenomenon. Video-assisted spinal surgery (VATS) and Mini open thoracotomy, thoracoscopically assisted (MOT-TA) allow for the performing of multi level discectomies and soft tissue release, as an anterior adjunct to posterior spine fusion, through minimal approach to the thoracic spine in scoliosis surgery. During the last year we have begun using the MOT-TA for anterior thoracic spine release and fusion, as the first step in releasing, reducing, and fusing large and stiff scoliotic curves, utilizing standard surgical instrumentation and techniques.

Materials and Methods: Mini-Thoracotomy Thoracoscopic Assisted was performed on 15 patients, age 4 to 48 (mean 20 years old) between January 2000 to present. There was a female predominance (12:3). In the group, 13 patients were scoliosis patients and 2 were kyphosis patients. All patients underwent anterior release and discectomy before performing posterior fusion. A mean of 4 discs (range 3 to 5 discs) was excised at surgery. The mean Cobb angle was 62°. No anterior instrumentation was placed in the first 14 cases. In case No. 15 an anterior crew-rod construct was placed through the mini thoracotomy incision.

Technique: MOT-TA is performed with the patient positioned in a lateral decubitus with the convex side of the scoliotic curve up through a 5–7 cm skin incision above the apical vertebra obliquely from the posterior to the middle axillary line.

Results: There was a short learning curve associated with the technique, which proved to be an easy and straight forward surgical technique. Pre-operative thoracic Cobb angle measured 50°–80° (average 62°) that bends to 30°–66° on the pre-operative thoracic bend films (average 45°). The pot-operative thoracic Cobb angle measured 15°–38° (average 28°). The overall curve correction was 59% on average. The anterior soft tissue releases and discectomies were a quick and relatively “dry” part of the surgery. Estimated blood loss ranged 50–800cc, less than a quarter of the total intra-operative blood loss averaging 220cc out of 1227cc of the total EBL. Anterior surgery time ranged 100 to 170 min averaging 147min for mean of 6.1 discs (range 4 to 9 discs). When compared to the total operative time, the anterior part of the surgery took about a 1/3 of the total surgery time.

Discussion: The results of the study show that the mini open thoracotomy, thoracoscopically assisted, for anterior thoracic spine release and discectomies is a fast, easy to learn technique with a short learning curve leading to complete anterior release, short operative time, allowing same day front and back surgery with no difficulty in performing internal thoracoplasty that results in structural and cosmetically superior outcome. In the hands of an experienced surgeon, the usage of VATS could be an effective and beneficial in scoliosis surgery; however, in the case of less experienced surgeon, who has no experience in thoracoscopic surgery, the MOT-TA could be an elegant and useful way to perform the technically demanding anterior discectomies and releases in severely deformed and rigid scoliotic spine. In our last case we have demonstrated the ability to instrument the anterior spine utilizing the same mini thoracotomy incision, this advance will be carried further to more extensive instrumentation in the future.

In conclusion: Mini open thoracotomy, thoracoscopically assisted, for anterior thoracic spine release and fusion is a faster, easier, cosmetically superior and surgically justified procedure.