Allograft versus autograft for pediatric posterior cervical and occipito-cervical fusion: a systematic review of factors affecting fusion rates

Autologous rib grafts for craniocervical junction surgery in children: a clinical application

OBJECTIVE

Autologous iliac bone is commonly used as a bone graft material to achieve solid fusion in craniocervical junction (CVJ) surgery. However, the developing iliac bone of children is less than ideal as a bone graft material. The matured rib bone of children presents a potential substitute material for iliac bone. The aim of this study was to evaluate the efficacy of autologous rib grafts for craniocervical junction surgery in children.

METHODS

The outcomes of 10 children with abnormalities of the craniocervical junction who underwent craniocervical junction surgery between January 2020 and December 2022 were retrospectively reviewed. All patients underwent posterior fusion and internal fixation surgery with autologous rib grafts. Pre- and post-operative images were obtained and clinical follow-ups were conducted to evaluate neurological function, pain level, donor site complications, and bone fusion rates.

RESULTS

All surgeries were successful. During the 8- to 24-month follow-up period, all patients achieved satisfactory clinical results. Computed tomography at 3-6 months confirmed successful bone fusion and regeneration of the rib defect in all patients with no neurological or donor site complications.

CONCLUSION

Autologous rib bone is a safe and effective material for bone grafting in craniocervical junction fusion surgery for children that can reduce the risks of donor site complications and increase the amount of bone graft, thereby achieving a higher bone fusion rate.

Comparison of structural occipital and iliac bone grafts for instrumented atlantoaxial fusions in pediatric patients: Radiologic research and clinical outcomes

Background

Structural autografts harvested from the iliac bone have been used in atlantoaxial fusion; they have been the gold standard for years. However, emerging occipital bone grafts have the advantage of avoiding donor-site morbidity and complications. Thus, we compared the clinical outcomes of structural autografts from the occipital bone or iliac crest and discussed the clinical significance of occipital bone grafts in pediatric patients.

Methods

Pediatric patients who underwent posterior fusion using occipital bone grafts (OBG) or iliac bone grafts (IBG) between 2017 and 2021 were included in this study. Data on clinical outcomes, including operation time, estimated blood loss, length of hospitalization, complications, fusion rate, and fusion time, were collected and analyzed. Additionally, 300 pediatric patients who underwent cranial computed tomography scans were included in the bone thickness evaluation procedure. The central and edge thicknesses of the harvested areas were recorded and analyzed.

Results

Thirty-nine patients were included in this study. There were no significant differences in patient characteristics between the OBG and IBG groups. Patients in both groups achieved a 100% fusion rate; however, the fusion time in the OBG group was significantly longer than that in the IBG group. Estimated blood loss, operation time, and length of hospitalization were significantly lower in the OBG group than those in the IBG group. The surgery-related complication rate was lower, but not significantly, in the OBG group than that in the IBG group. For occipital bone thickness evaluation, a significant difference in the central part of the harvesting area was found between the young and old groups, with no significant sex differences.

Conclusion

The use of OBG for atlantoaxial fusion is acceptable for pediatric patients with atlantoaxial dislocation, avoiding donor-site morbidity and complications.

Novel Surgical Technique for Adolescent Idiopathic Scoliosis: Minimally Invasive Scoliosis Surgery

Despite advancements in instruments and surgical techniques for adolescent idiopathic scoliosis (AIS) surgery, conventional open scoliosis surgery (COSS) is usually required to achieve satisfactory deformity correction using various distinct surgical techniques, such as rod derotation, direct vertebral rotation, facetectomies, osteotomies, and decortication of the laminae. However, COSS is accompanied by significant blood loss and requires a large midline skin incision. Minimally invasive surgery (MIS) has evolved enormously in various fields of spinal surgery, including degenerative spinal diseases. MIS of the spine has some advantages over conventional surgery, such as a smaller incision, less blood loss and postoperative pain, and lower infection rates. Since the introduction of MIS for AIS in 2011, MIS has been reported to have comparable outcomes, including correction rate with some usual advantages of MIS. However, several complications, such as dislodgement of rods, wound infection, and hypertrophic scar formation, have also been reported in the initial stages of MIS for AIS. We devised a novel approach, called the coin-hole technique or minimally invasive scoliosis surgery (MISS), to minimize these complications. This article aimed to introduce a novel surgical technique for AIS and provide a preliminary analysis and up-to-date information regarding MISS.

Three-Dimensional-Printed Drill Guides for Occipitothoracic Fusion in a Pediatric Patient With Occipitocervical Instability

BACKGROUND

Pediatric occipitothoracic fusion can be challenging because of small size pedicles and thin occipital bone. Three-dimensional (3D) printing technology can help with accurate screw insertion but has not been described for occipital keel plate positioning so far.

OBJECTIVE

To describe the novel use of 3D technology to position occipital keel plates during pediatric occipitothoracic fixation.

METHODS

A young boy with segmental spinal dysgenesis presented with asymmetrical pyramidal paresis in all limbs. Developmental abnormities of the cervical spine caused a thinned spinal cord, and because of progressive spinal cord compression, surgical intervention by means of occipitothoracic fixation was indicated at the age of 3 yr.Because of the small-size pedicles and thin occipital bone, the pedicle screws and occipital plates were planned meticulously using 3D virtual surgical planning technology. The rods were virtually bent in order to properly align with the planned screws. By means of 3D-printed guides, the surgical plan was transferred to the operating theater. For the occipital bone, a novel guide concept was developed, aiming for screw positions at maximal bone thickness.

RESULTS

The postoperative course was uneventful, and radiographs showed good cervical alignment. After superimposing the virtual plan with the intraoperative acquired computed tomography, it was confirmed that the occipital plate positions matched the virtual plan and that pedicle screws were accurately inserted without signs of breach.

CONCLUSION

The use of 3D technology has greatly facilitated the performance of the occipitothoracic fixation and could, in the future, contribute to safer pediatric spinal fixation procedures.

Cervical Pediatric Spine Trauma Managed With Open Spinal Fixation and Instrumentation and a Review of the Literature

Cervical spine injuries in the pediatric population are rare. Most injuries to the cervical spinal cord and vertebral column can be managed nonoperatively; however, surgical management may be required in certain clinical scenarios. A posterior surgical approach has been previously preferred; however, the utilization of anterior spinal fixation and instrumentation has been limited. We present a small case series of patients presenting with a traumatic cervical spine injury and detail the feasibility of craniocervical junction (CVJ) and subaxial spinal fixation in the pediatric population.

We report four cases involving pediatric patients, all of whom presented with cervical spine injuries necessitating operative intervention using a combination of the anterior and posterior operative approaches. All four patients recovered well, did not require surgical revision, and were neurologically intact at the last follow-up. 

Therefore, we conclude that spinal arthrodesis is a safe, effective way to manage spinal injuries in the cervical spine following traumatic injury.

Pediatric Spine Trauma: A Brief Review

Pediatric spinal trauma is a broad topic with nuances specific to each anatomic region of the spinal column. The purpose of this report is to provide a brief review highlighting the most important and common clinical issues regarding the diagnosis and management of pediatric spine trauma. Detailed descriptions of imaging findings along with specific operative and nonoperative management of each fracture and dislocation type are beyond the scope of this review.

Fusion rates support wired allograft combined with instrumented craniocervical fixation in the paediatric population

Background

Occipitocervical and atlantoaxial instability in the pediatric population is a rare and challenging condition to treat. Variable surgical techniques have been employed to achieve fusion. The study aimed to assess bony fusion with rigid craniocervical fixation using an allograft bone block to serve as scaffold for bony fusion.

Methods

This is a single center case series from a tertiary referral neurosurgical center. The series includes 12 consecutive pediatric patients with rigid craniocervical fusion between 2006 and 2014. The primary outcome was bony fusion as assessed by computed tomography and flexion-extension radiographs. The authors did not receive external funding for this study.

Results

Twelve patients (age 1–15 years) were operated with a median imaging follow-up time of 22 months (range 6–69 m). A modified Gallie fusion technique with a tightly wired allograft bone block was used in 10 of 13 procedures. One patient underwent re-fixation due to screw breakage. Eleven out of 13 procedures resulted in a stable construct with bony fusion. All 10 patients operated with the modified Gallie fusion technique with sublaminar wiring of allograft bone block had bony fusion. No post-operative complications of the posterior fixation procedure were noted.

Conclusions

The modified Gallie fusion technique with allograft bone block without post-operative immobilization achieved excellent fusion. We conclude there is no need to use autograft or BMPs in craniocervical fusion in the pediatric population, which avoids related donor-site morbidity.

Level of evidence

Level IV—case series; therapeutic.

Occipitocervical or C1-C2 fusion using allograft bone in pediatric patients with Down syndrome 8 years of age or younger

Sufficient internal fixation for occipitocervical (OC) or C1-C2 instability in pediatric patients with Down syndrome is difficult owing to small osseous structures, congenital deformities, and immature ossification. The purpose of this study was to evaluate the clinical outcomes of patients aged 8 years or younger with Down syndrome who underwent OC or C1-C2 fusion using freeze-dried allograft as bone graft substitute. The participants included seven consecutive patients aged 8 years or younger with Down syndrome who were treated for upper cervical disorders with posterior OC or C1-C2 fusion using freeze-dried allografts at our hospital between 2007 and 2016 and had a minimum follow-up of 1 year. Postoperative flexion/extension cervical radiography and computed tomography were repeated at 3 months after surgery before removal of the collar. The modified McCormick scale was used to grade functional status. The seven patients had an age range of 5-8 years (mean: 5.9 years). The mean follow-up period was 36 months (12-120 months). Six patients had os odontoideum and one had basilar invagination. Three patients underwent C1-C2 fusion, and in all cases, bilateral C1 lateral mass screws and bilateral C2 pedicle screws were used. Four patients underwent OC fusion, and in three of these cases, occipital and bilateral pedicle screws were used. One patient underwent reoperation because of occipital screw back-out with autograft; therefore, C2 lamina screws were added to pedicle screws. Solid bony fusion was achieved, and stable constructs were maintained on radiography in all patients, without infection or implant failure. In this study, we used freeze-dried allograft as a bone graft substitute, and we were able to detect bony trabeculae at the graft-recipient interface on lateral cervical radiographs and on reconstructed sagittal computed tomographic images in all patients. These results suggest that use of allograft is effective for treatment of upper cervical spine abnormalities in pediatric patients with Down syndrome.

Autogenic Rib Graft for Atlantoaxial and Occipitocervical Fixation in Pediatric Patients

Study Design

Retrospective case series.

Purpose

To evaluate surgical outcomes and effectiveness of an autogenic rib graft for upper cervical fixation in pediatric patients.

Overview of Literature

Autogenic bone grafts have long been considered the ‘gold standard’ bone source for posterior cervical fusion in pediatric patients. However, there are some unsolved problems associated with donor-site morbidity and amount of bone grafting.

Methods

We studied five consecutive pediatric patients who underwent atlantoaxial fixation or occipitocervical fixation (OCF) using an autogenic rib graft with at least 2 years of follow-up (mean age, 9.8 years; mean follow-up period, 73.0 months). Two patients underwent OCF without screw-rod constructs and three patients with screw-rod constructs. Autogenic rib grafts were used in all patients. We evaluated the surgical outcomes including radiographic parameter, bony union, and perioperative complications.

Results

The atlantoaxial interval (ADI) was corrected from 11.6 to 6.0 mm, and the C1–2 angle was corrected −14.8° to 7.8°. The C2–7 angle was reduced from 31° to 9° spontaneously. Two patients with OCF required revision surgery due to loss of correction. Patients did not experience any complication associated with the donor sites (rib bone grafts). Six months postoperation X-rays clearly showed regeneration of the rib at the donor sites. Bony fusion was achieved in all patients; however, bony fusion occurred more slowly in patients without screw-rod constructs compared with patients with screw-rod constructs. Bone regeneration of the rib was observed in all patients with no complications at the donor site.

Conclusions

Autogenic rib grafts have advantages of potential bone regeneration, high fusion rate, and low donor-site morbidity. In addition, a screw-rod construct provides better bony fusion in pediatric patients with OCF and atlantoaxial fixation.

Pediatric parapharyngeal infection resulting in cervical instability and occipital-cervical fusion-case report and review of the literature

Parapharyngeal infection is the most common deep neck space infection in children and, in rare instances, can result in bony destruction of the cervical spine. We report one such case that required occipital to cervical fusion and halo-vest fixation. We also review the literature and discuss the etiology, diagnosis, and treatment options for managing pediatric cervical bony destruction secondary to infection.

Use of Recombinant Human Bone Morphogenetic Protein-2 at the C1-C2 Lateral Articulation without Posterior Structural Bone Graft in Posterior Atlantoaxial Fusion in Adult Patients

BACKGROUND

Posterior atlantoaxial fusion is an important armamentarium for neurosurgeons to treat several pathologies involving the craniovertebral junction. Although the potential advantages of recombinant human bone morphogenetic protein-2 (rhBMP-2) are well documented in the lumbar spine, its indication for C1-C2 fusion has not been well characterized. In our institution, we apply rhBMP-2 to the C1-C2 joint either alone or with hydroxyapatite, locally harvested autograft chips, and/or morselized allogenic bone graft for selected cases-without conventional posterior structural bone graft. We report the clinical outcomes of the surgical technique to elucidate its feasibility.

METHODS

We performed a single-center, retrospective review of data from 2008 to 2016 and identified 69 patients who had undergone posterior atlantoaxial fusion with rhBMP-2. The clinical records of these patients were reviewed, and the baseline characteristics, operative data, and postoperative complications were collected and statistically analyzed.

RESULTS

The average age of the 69 patients was 60.8 ± 4.5 years, and 55.1% were women. With an average follow-up period of 21.1 ± 4.2 months, the C1-C2 fusion rate was 94.3% (65 of 69), and the average time to fusion was 11.4 ± 2.6 months (range, 5-23). The overall reoperation rate was 10.1% (7 of 69), with instrumentation failure in 7 patients (10.1%), adjacent segment disease in 2 (2.9%), and postoperative dysphagia and dyspnea in 2 patients (2.9%). No ectopic bone formation or soft tissue edema developed.

CONCLUSIONS

Although retrospective and from a single center, our study has shown that rhBMP-2 usage at the C1-C2 joint without posterior structural bone grafting is a safe and reasonable surgical option.

A Modified Technique for Occipitocervical Fusion Using Compressed Iliac Crest Allograft Results in a High Rate of Fusion in the Pediatric Population

BACKGROUND

In children, high rates of occipitocervical (OC) fusion have been demonstrated with the use of rigid instrumentation in combination with harvested autograft, with or without bone morphogenetic protein (BMP). Historically, the use of allograft materials demonstrated inferior OC fusion outcomes compared with autograft. However, autograft harvest harbors an increased risk of patient morbidity, and the use of BMP is costly and controversial in children. Thus, there remains a need for safer, less costly, yet efficacious techniques for OC fusion in the pediatric population.

METHODS

We retrospectively reviewed the charts of patients younger than 21 years of age who underwent OC fusion with structural allograft placement at our institution from 2010 to 2015. Data collected included age, sex, follow-up duration, fusion outcomes, and postoperative complications.

RESULTS

A total of 19 patients (8 female and 11 male) underwent OC fusion with our surgical technique. Mean age was 8.5 ± 4.3 years. Radiographic follow up data were available for 18 of 19 patients. One patient was lost to clinical follow up but had radiographic confirmation of fusion. Thus, 18 of 18 (100%) of patients with radiographic follow-up achieved successful arthrodesis as determined by computed tomography. Median duration to documented fusion was 4.5 months. Clinical follow-up was available for 17 of 19 patients and was on average 18.8 ± 13.5 months. One patient required reoperation for graft fracture 8 months after radiographic confirmation of successful fusion. There were no vertebral artery injuries or other postoperative complications.

CONCLUSIONS

We demonstrate a modified technique for OC fusion in children with unique structural allograft shaping and affixation, leading to excellent fusion outcomes at follow up. This technique obviates the need for autograft harvest or BMP, and may decrease postoperative morbidity.

Instrumented fusion in a 12-month-old with atlanto-occipital dislocation: case report and literature review of infant occipitocervical fusion

BACKGROUND

The treatment of atlantoaxial dislocation in very young children is challenging and lacks a consensus management strategy.

DISCUSSION

We review the literature on infantile occipitocervical (OC) fusion is appraised and technical considerations are organized for ease of reference. Surgical decisions such as graft type and instrumentation details are summarized, along with the use of bone morphogenic protein and post-operative orthoses.

ILLUSTRATIVE CASE

We present the case of a 12-month-old who underwent instrumented occipitocervical (OC) fusion in the setting of traumatic atlanto-occipital dislocation (AOD).

CONCLUSION

Occipitocervical (OC) arthrodesis is obtainable in very young infants and children. Surgical approaches are variable and use a combination of autologous grafting and creative screw and/or wire constructs. The heterogeneity of pathologic etiology leading to OC fusion makes it difficult to make definitive recommendations for surgical management.

Posterior arch C-1 screw technique: a cadaveric comparison study

OBJECTIVE

Posterior atlantoaxial stabilization and fusion using C-1 lateral mass screw fixation has become commonly used in the treatment of instability and for reconstructive indications since its introduction by Goel and Laheri in 1994 and modification by Harms in 2001. Placement of such lateral mass screws can be challenging because of the proximity to the spinal cord, vertebral artery, an extensive venous plexus, and the C-2 nerve root, which overlies the designated starting point on the posterior center of the lateral mass. An alternative posterior access point starting on the posterior arch of C-1 could provide a C-2 nerve root–sparing starting point for screw placement, with the potential benefit of greater directional control and simpler trajectory. The authors present a cadaveric study comparing an alternative strategy (i.e., a C-1 screw with a posterior arch starting point) to the conventional strategy (i.e., using the lower lateral mass entry site), specifically assessing the safety of screw placement to preserve the C-2 nerve root.

METHODS

Five US-trained spine fellows instrumented 17 fresh human cadaveric heads using the Goel/Harms C-1 lateral mass (GHLM) technique on the left and the posterior arch lateral mass (PALM) technique on the right, under fluoroscopic guidance. After screw placement, a CT scan was obtained on each specimen to assess for radiographic screw placement accuracy. Four faculty spine surgeons, blinded to the surgeon who instrumented the cadaver, independently graded the quality of screw placement using a modified Upendra classification.

RESULTS

Of the 17 specimens, the C-2 nerve root was anatomically impinged in 13 (76.5%) of the specimens. The GHLM technique was graded Type 1 or 2, which is considered “acceptable,” in 12 specimens (70.6%), and graded Type 3 or 4 (“unacceptable”) in 5 specimens (29.4%). In contrast, the PALM technique had 17 (100%) of 17 graded Type 1 or 2 (p = 0.015). There were no vertebral artery injuries found in either technique. All screw violations occurred in the medial direction.

CONCLUSIONS

The PALM technique showed statistically fewer medial penetrations than the GHLM technique in this study. The reason for this is not clear, but may stem from a more angulated ”up-and-in” screw direction necessary with a lower starting point.