Journal of Musculoskeletal Research

Objective: This study investigated Hounsfield unit (HU) differences in adult spinal deformity (ASD) surgery patients with and without proximal junctional kyphosis (PJK), a common complication.

Summary Background Data: Previous studies have identified osteoporosis as a PJK risk factor, and CT scanning is a valuable tool for detecting osteoporosis through HU measurements. The study aimed to determine the level of HU difference between patients diagnosed with and without PJK.

Methods: We conducted a meta-analysis using a random-effects model of randomized controlled trials and cohort studies that assessed HUs for ASD surgery patients who developed PJKs. We searched in PubMed, Embase, Ovid, The Cochrane Library, and Web of Science up to October 2022 and had two authors extract data and evaluate bias.

Results: Four cohort studies with 250 patients were included in this study. Measurements of HUs at upper instrumented vertebra (UIV) and UIV+1 showed significant differences between PJKs and non-PJKs. (Mean difference (MD) at UIV: −25.36, 95% CI: −39.16, −11.56, p = 0.0003; MD at UIV+1: −21.06, 95% CI: −38.25, −3.88, p = 0.02).

Conclusions: The study found measuring HUs of UIV and UIV+1 can predict the occurrence of PJK in ASD surgery. Further prospective studies are warranted to validate our findings.

Purpose: Most spinal osteotomy procedures applied for spinal deformity and concomitant malalignment cases are associated with varied complications. This study evaluates the short- to midterm clinical and radiographic efficacy of the transpedicular anterior opening osteotomy technique.

Methods: We retrospectively enrolled six patients who underwent transpedicular anterior opening osteotomy due to symptomatic rigid kyphotic deformity from May 2005 to 2016. During surgery, we created a new fracture line at the collapsed anterior vertebral body through bilateral pedicles, filled spaces with compacted bone grafts while preserving posterior elements, including lamina, and secured structure using posterior instrumentation. The kyphotic Cobb angle, Visual Analog Scale (VAS), and Oswestry Disability Index (ODI) before and after surgery were measured and analyzed.

Results: The mean preoperative kyphotic Cobb angle was $31.41\pm 4.77^{\circ }$ while the postoperative value was $15.75\pm 1.66^{\circ }$. The mean correction angle was $15.55\pm 6.66^{\circ }$. The mean follow-up duration was $50.17\pm 44.16$ months. During the final follow-up, the mean kyphotic angle was not statistically different from the postoperative values. All patients with documented VAS Back and ODI had improved values postoperatively.

Conclusions: Transpedicular anterior opening osteotomy with posterior element preservation improves clinical outcomes and is safe and effective in correcting regional, fixed kyphotic deformities.

Thoracolumbar (T–L) fracture may create focal kyphosis accompanied by altered sagittal alignment, instability and potential neurological deficits. Surgical intervention for post-traumatic T–L kyphosis aims to restore sagittal balance, release compromised neural structures, and to improve the symptoms related to the malalignment. It is best indicated when there is a progression of kyphotic deformity, and/or when there are new or progressive neurological deficits. A kyphotic deformity $\ge 30^{\circ }$ is susceptible to persistent chronic pain in the kyphotic region and surgical correction is often required. Those with posterior ligamentous complex injury may also warrant surgical correction as there is a higher risk of kyphosis progression. A number of surgical procedures could be employed to correct post-traumatic T–L kyphosis. Spinal osteotomies are often needed to improve global, sagittal or coronal balance including in the late and fixed post-traumatic kyphosis. Based on different extent of focal kyphosis and global malalignment, surgical options may include posterior column osteotomy (PCO), pedicle subtraction osteotomy (PSO), disc-bone osteotomy (DBO), vertebral column resection (VCR) or closing opening wedge osteotomy (COWO). The type of spinal osteotomy utilized to correct post-traumatic T–L kyphosis should be chosen based on the severity of the deformity, the alignment of the spine, and the surrounding structures. In the meantime, potential complications should be reduced with novel techniques and proper constructs. When all associated factors are considered, surgical correction composing a suitable spinal osteotomy can be a beneficial and rewarding procedure for patients with post-traumatic T–L kyphosis.

Study Design: Retrospective case analysis and systematic literature review.

Objective: To comprehensively review minimally invasive surgery (MIS) for post-traumatic kyphosis.

Methods: A systematic PubMed search was conducted for MIS and kyphotic deformities were published between 2012 and 2022. Sixteen patients between 2017 and 2021 met the criteria. Demographic data, surgical characteristics, and full-length radiographic parameters were collected pre- and post-operatively, and at final follow-up.

Results: Twenty-three articles were included. The mean age was 67 years, and the mean follow-up was 17 months. The mean operative time was 331 min and blood loss was 252 ml. Pre-operative radiographic outcomes were as follows: Lumbar lordosis (LL), $16.84\pm 26.40^{\circ }$; pelvic incidence (PI), $48.95\pm 14.34^{\circ }$; PI-LL mismatch, $32.11\pm 31.92^{\circ }$; pelvic tilt (PT), $32.74\pm 10.41^{\circ }$; and sagittal vertical axis (SVA), $95.33\pm 59.62$ mm. At the final follow-up, LL was $19.98\pm 16.16^{\circ }$ ($P$ = 0.51229), PI was $50.82\pm 10.19^{\circ }$ ($P$ = 0.61438), PI-LL mismatch was $30.84\pm 17.18^{\circ }$ ($P$ = 0.74696), PT was $27.14\pm 10.28^{\circ }$ ($P$ = 0.00386), and SVA was $49.73\pm 25.51$ mm ($P$ = 0.00465). The mean ODI and VAS scores for back pain at baseline and at 96 months follow-up were 33.2–19.7 and 8.4–2.5, respectively.

Conclusion: Age-adjusted MIS provides correction of sagittal alignment for posttraumatic kyphosis that satisfies patient demand.

Pediatric kyphosis is a specific disease entity of sagittal plane back deformity in pediatric and adolescent patients. Smooth round kyphosis is frequently encountered in this age and it can be differentiated as posture kyphosis and Scheuermann’s disease. Other types of kyphosis include syndromic kyphosis, congenital kyphosis and miscellaneous causes. In this paper, we will discuss the diagnosis and evaluation methods, treatment options and surgery for pediatric kyphosis. The doctors should be familiar with different surgical approach and osteotomy methods to facilitate prognosis, minimize complications and improve patient’s quality of life.

Spinal tuberculosis typically affects the vertebral bodies, resulting in various degrees of kyphosis. Children <10 years, thoraco-lumbar spine affliction, late presentation, vertebral loss >1.5 bodies and presence of spine at risk signs reasonably predict patients who are prone for worsening kyphosis during both active and healed stages of the disease. Untreated kyphosis is ominous as it can result in spinal fatigue, neurological deficit, cosmetic disfigurement, and respiratory insufficiency. Kyphosis greater than $30^{\circ }$ and presence of risk factors for worsening kyphosis are considered as indications for surgery in active tuberculosis. Different surgical methods have been described with their own merits and demerits. Currently, posterior approach with or without anterior reconstruction is considered the standard technique as it is safe, efficacious, convenient, and versatile.

Various osteotomy techniques have been proposed to correct the kyphotic deformities caused by ankylosing spondylitis (AS). However, no technique could cater to all AS-related deformities well regarding the various mobility of calcified discs and the severity of deformities. Therefore, a thorough understanding of the strength and weaknesses of each method is essential. Then, a strategic approach could be formulated to select the most appropriate technique for a specific patient so as to have a correction operation with effectiveness, safety, and surgical simplicity. Among all preoperative examinations, the evaluation of disc mobility and the severity of kyphotic deformity is mandatory, which constitutes the base for the selection of osteotomy techniques. Since posterior column osteotomy (PCO) is the simplest technique, it should be used as much as possible. If up to three mobile discs are preserved, and the severity of the deformity is only moderate, e.g. the global thoracolumbar angle is less than $60^{\circ }$, contemporary poly-segmental PCO is selected. Staged PCO (SPCO), proposed by the authors, is the enhanced PCO with more excellent correction capability. If the disc mobility is not favorable enough, SPCO can be considered instead. PSO is the most versatile technique, capable of correcting all kinds of deformities regardless of disc mobility and severity of the kyphosis. This technique can be used in every case if surgical complexity is not a concern to the operator. Especially, PSO is the exclusive indication for those firmly ankylosed deformities without any mobile disc.

Purpose: Surgical treatment for adult spinal deformity (ASD) in patients with Parkinson’s disease (PD) is challenging and is associated with a significant risk of postoperative mechanical complications, such as rod breakage, pseudoarthrosis and proximal junctional failure. We herein report the surgical results of three-column osteotomy with pedicle screw fixation combined with compression hook for ASD associated with PD.

Methods: We retrospectively investigated four patients with ASD due to PD who underwent three-column osteotomy with posterior instrumentation. The compression hook system placed on the laminae was used for closure of the osteotomy site during surgery and reinforcement of pedicle screw fixation. Surgical outcomes and radiographical parameters were analyzed.

Results: Lumbar lordosis was improved from $-25^{\circ }\pm 18^{\circ }$ preoperatively to $51^{\circ }\pm 7^{\circ }$ postoperatively, and $48^{\circ }\pm 5^{\circ }$ at the final follow-up examination. The sagittal vertical axis was restored from 297 ± 104 mm preoperatively to 41 ± 13 mm postoperatively, and 72 ± 23 mm at the final follow-up examination. The preoperative VAS (88 ± 14 mm) for low back pain was significantly improved at the final follow-up examination (14 ± 28 mm). Walking disturbance due to low back pain was improved in all patients. No patients had mechanical failure (e.g. rod fracture, pseudarthrosis, or junctional failure) after surgery.

Conclusion: The use of compression hooks to supplement pedicle screw fixation is beneficial for performing safe osteotomy closure during surgery and preventing postoperative mechanical failures, and may be a useful option when performing three-column osteotomy for ASD associated with PD.

Cervical kyphosis in ankylosing spondylitis is a debilitating disease for the patient as well as a complex deformity for the surgeon to treat. Ankylosing spondylitis patients should be assessed clinically and radiologically to determine their indications for surgery. Thorough preoperative evaluation of the patient and surgical planning are critical to the success of the corrective surgery. Various kyphotic deformities and osteotomy classifications can be taken into consideration for surgical planning. There are various types of corrective procedures for the treatment of cervical kyphosis. For patients with ankylosing spondylitis and chin-on-chest deformity, pedicle subtraction osteotomy offers the largest angle of correction. However, pedicle subtraction osteotomy is highly technically demanding and associated with a substantial risk for neurovascular complications.