Surgical outcome after treatment of thoracolumbar spinal stenosis in adults with achondroplasia.

PURPOSE: To describe the complications and the outcome of patients with achondroplasia undergoing thoracolumbar spinal surgery. METHODS: Retrospective analysis of prospectively collected data of all patients with achondroplasia undergoing surgery within the years 1992-2021 at the thoracic and/or lumbar spine. The outcome was measured by analyzing the surgical complications and revisions. The patient-rated outcome was assessed with the COMI score from 2005 onwards. RESULTS: A total of 15 patients were included in this study undergoing a total of 31 surgeries at 79 thoracolumbar levels. 12/31 surgeries had intraoperative complications consisting of 11 dural tears and one excessive intraoperative bleeding. 4/18 revision surgeries were conducted due to post-decompression hyperkyphosis. The COMI score decreased from 7.5 IQR 1.4 (range 7.1-9.8) preoperatively to 5.3 IQR 4.1 (2.5-7.5) after 2 years (p = 0.046). CONCLUSION: Patients with achondroplasia, the most common skeletal dysplasia condition with short-limb dwarfism, are burdened with a congenitally narrow spinal canal and are commonly in need of spinal surgery. However, surgery in these patients is often associated with complications, namely dural tears and post-decompression kyphosis. Despite these complications, patients benefit from surgical treatment at a follow-up of 2 years after surgery.

Validation of a surgical invasiveness index in patients with lumbar spinal disorders registered in the Spine Tango registry.

INTRODUCTION: Being able to quantify the invasiveness of a surgical procedure is important to weigh up its associated risks, since invasiveness governs the blood loss, operative time and likelihood of complications. Mirza et al. (Spine (Phila Pa 1976) 33:2651-2661, 2008) published an invasiveness index for spinal surgery. We evaluated the validity of a modified version of the Mirza invasiveness index (mMII), adapted for use with registry data. METHODS: A cross-sectional analysis was performed with data acquired from the Spine Tango registry including 21,634 patients. The mMII was calculated as the sum of six possible interventions on each vertebral level: decompression, fusion and stabilization either on anterior or posterior structures. The association between the mMII and blood loss, operative time and complications was evaluated using multiple regression, adjusting for possible confounders. RESULTS: The mean (± SD) mMII was 3.9 ± 5.0 (range 0-40). A 1-point increase in the mMII was associated with an additional blood loss of 12.8% (95% CI 12.6-13.0; p < 0.001) and an increase of operative time of 10.4 min (95% CI 10.20-10.53; p < 0.001). The R2 for the blood loss model was of 43% and for operative time, 47%. The mean mMII was significantly (p < 0.001) higher in patients with surgical complications (4.5 ± 5.6) and general medical complications (6.5 ± 7.0) compared to those without (3.8 ± 4.9). Our results were comparable to those reported in the original publication of Mirza et al. CONCLUSION: The mMII appeared to be a valid measure of surgical invasiveness in our study population. It can be used in predictor models and to adjust for surgical case-mix when comparing outcomes in different studies or different hospitals/surgeons in a registry.

Back Pain and Its Change After Surgery in Adolescents and Young Adults With Idiopathic Scoliosis.

STUDY DESIGN: A retrospective analysis of prospectively collected data from patients aged 12-30 years, operated for AIS in our hospital from 2005 to 2014 and registered in our local patient outcomes database linked to EUROSPSINE's Spine Tango Registry. OBJECTIVES: To investigate whether in patients with AIS and notable back pain surgery is associated with significant pain relief and whether age influences outcome. SUMMARY OF BACKGROUND DATA: Few studies have investigated the association between adolescent idiopathic scoliosis and back pain and the influence of age on the relief of back pain after surgical correction of the deformity. METHODS: Preoperatively and up to two years' postoperatively, patients completed the Core Outcome Measures Index, which includes two 0-10 scales for back pain and leg/buttock pain. A score of 4/10 or more is considered "relevant pain." RESULTS: We identified 85 patients with AIS (74 (87%) females) in the database; 60 were aged 12-18 years (mean 15.5 ± 1.7 years) and 25 were 19-30 years (mean 22.5 ± 3.1 years). There were no significant differences (p > .05) between the age groups for coronal Cobb angles of the main curves or Lenke curve types, and these curves showed no correlation with pain intensity (p > .05). Back pain was correlated with age (r = 0.31, p = .004). Preoperatively, 42% patients had a back pain score of ≥4/10 (52% in adults, 38% in adolescents). Just 8% patients had a leg pain score of ≥4/10 (16% in adults, 5% in adolescents). Those with notable back pain showed a significant (p < .0001) improvement two years after surgery. However, 24% of patients with no back pain at baseline showed a worsening of pain by 2 (out of 10) points or more two years postoperatively. There was no significant difference in the extent of improvement in older and younger patients (p = .22). CONCLUSION: In patients undergoing surgery for correction of AIS, back pain is correlated with age. In those with relevant back pain at baseline, surgery is associated with a statistically significant and clinically relevant reduction of pain 24 months later, in skeletally mature young adults and adolescents alike. LEVEL OF EVIDENCE: Level III.

Prospective study of the effect of pedicle screw placement on development of the immature vertebra in an in vivo porcine model.

INTRODUCTION: There is increasing awareness of the need for pedicle screw constructs in the treatment of spinal deformities in very young children. However, the long-term effects of pedicle screws on the immature spine are still unclear. We used a porcine model to analyze the morphological changes of the spinal canal and vertebral body in response to the placement of pedicle screws. METHODS: 13 newborn pigs were operated on. Each pig received a single pedicle screw at the L2 level. After a tenfold increase in body weight (7 months later), the symmetry of the spinal canal and vertebral body was measured on CT scans of the investigational (L2) and control (L3) levels in terms of the angulations of the instrumented and non-instrumented halves of the vertebral body and spinal canal. RESULTS: After 7 months, the normalised vertebral body angle had reduced on the non-screw side and increased on the screw side, indicating asymmetry in vertebral body growth in the axial plane. The difference was significant (p = 0.009). However, there was no significant difference between the screw and non-screw sides for the spinal canal angles at the L2 level at either the intraoperative or 7-month follow-up assessment (each p > 0.05). CONCLUSIONS: Pedicle screws in the immature porcine spine have a significant effect on the development of the vertebral body. However, in the present study, no corresponding alteration of the morphology of the spinal canal was observed. Our results provide further support for the existing arguments in favour of pedicle screws when weighing up the many factors to be considered in creating a treatment plan for early onset scoliosis.