Spinous Process Splitting Laminectomy for Lumbar Spinal Stenosis: 2D Operative Video.

Degenerative lumbar spinal stenosis involves an acquired reduction in the spinal canal diameter due to osteoarthritic changes on the disk, facet joints, and ligaments and may result in spinal cord or cauda equina compression.1 This process may lead to pain radiating to the legs, neurogenic claudication, and neurologic deficit. First-line treatment includes conservative care such as physical therapy, spinal injections, and lifestyle changes. If this strategy is insufficient to achieve symptom relief, surgical management is recommended.1,2 Surgery generally encompasses a decompression procedure through a posterior approach. There are several techniques to accomplish this in the context of severe bilateral stenosis including standard open laminectomy, unilateral laminectomy with bilateral decompression, and a tubular approach with bilateral decompression (e.g., "over-the-top technique").2 Among these, the spinous process splitting laminectomy has emerged as a strategy that allows decompressing the spinal canal through a familiar anatomy to the surgeon while respecting paravertebral muscles.3,4 This technique involves exposure of the laminae by cutting through the spinous process and then separating both halves and muscles attached at the sides. The main advantage is that the insertion of these paravertebral soft tissues is preserved, the required retraction is reduced and postoperative pain is decreased.4 Moreover, the learning curve to achieve a successful decompression employing the splitting laminectomy is substantially shorter than with other minimally invasive approaches, such as tubular. This video aims to show the steps to perform this technique (Video 1). We report the case of a 74-year-old male who presented with left sciatica and neurogenic claudication. The images showed multilevel degenerative lumbar spinal stenosis, with severe bilateral compression at L4-5, without signs of instability. Surgical alternatives were discussed with the patient, and it was decided to perform an L4-5 spinous process splitting laminectomy. The patient had a good evolution with an unremarkable postoperative course.

20 Tips to Avoid and Handle Problems in the Placement of Percutaneous Pedicle Screws.

BACKGROUND: Two-dimensional fluoroscopy-guided percutaneous pedicle screw placement is currently the most widely applied instrumentation for minimally invasive treatment of spinal injuries requiring stabilization. Although this technique has advantages over open instrumentation, it also presents new challenges and specific complications. The objective of this study was to provide recommendations developed from the experience of several spinal surgeons at different minimally invasive spine surgery reference centers to solve specific problems and prevent complications during the learning curve of this technique. METHODS: An AO Spine Latin America minimally invasive spine surgery study group analyzed the most frequent complications and challenges occurring during the placement of >14,000 two-dimensional fluoroscopy-guided percutaneous pedicle screws at different centers over 15 years. Twenty tips considered most relevant to performing this technique, excluding problems directly related to specific brands of instruments, were presented. RESULTS: The 20 tips included the following: (1) positioning; (2) clean and painless; (3) fewer x-rays; (4) check the clock; (5) beveled tip; (6) transverse-rib-pedicle; (7) double Jamshidi; (8) hammer the Kirschner wire; (9) bent tip; (10) too loose, too tight; (11) new trajectory; (12) manual control; (13) start over; (14) Kirschner wire first; (15) adhesive drape control; (16) bend the rod; (17) lower rods; (18) freehand inner; (19) posterior fusion; (20) revision. CONCLUSIONS: Implementation of these tips might improve performance of this technique and reduce the complications related to percutaneous pedicle screw placement.

Partial Sacrectomy for Resection of a Sacral Chordoma: 2-Dimensional Operative Video.

Sacral chordomas are infrequent tumors that arise from remnants of the notochord. They are most often found in the sacrum and skull-base.1,2 These lesions rarely metastasize and usually have an indolent and oligosymptomatic clinical course. Chordomas show low sensitivity to standard radiation therapy and chemotherapy. Operative resection with wide resection margins offers the best long-term prognosis, including longer survival and local control.1,3 However, achieving a complete resection with oncological margins may be difficult because of the anatomic complexity of the sacrococcygeal region.4 The main complications of sacral resection include infections, wound closure defects, and anorectal and urogenital dysfunction. The rate of these complications is significantly increased when the tumor involves the S2 level or above. We report the case of a 64-yr-old male who presented with progressive sacrococcygeal pain and a feeling of incomplete evacuation. A heterogeneous, osteolytic lesion was found at the sacrococcygeal region. Full body imaging tests were negative for other lesions. A computed tomography (CT) guided biopsy was made. We usually use the midline approach in case we have to include the needle path in the resection. The pathology confirmed a sacrococcygeal, low-grade chordoma. We decided to perform an en bloc resection. A posterior, partial sacrectomy was planned distal to the S4 level.

[Spino-pelvic sagittal parameters in an asymptomatic population in Argentina]. / Parámetros sagitales espino-pélvicos en una población asintomática Argentina.

OBJECTIVES: To assess and describe spinal and pelvic sagittal parameters in a series of 100 Argentinian volunteers. METHODS: Lateral full-spine X-rays were obtained prospectively from 100 volunteers (30 males and 70 females), average age 34.1 years. All the volunteers were asymptomatic at the time of the study. Full-length left lateral spine radiographs (36'' cassette) were made using Kodak Elite CR equipment. The authors made determinations for the digital X-rays using Surgimap®, version 2.2.9.9.2. The following parameters were recorded: C7 SVA, C2-C7 CL, TK, LL, TPA, T1SPi, PI, PT, SS, L4-S1 angle, L1-L4 angle, PI-LL mismatch and CTPA. The data were analyzed using Medcalc 11.2 software. Descriptive statistics were calculated for each parameter according to its own measure score and distribution. Estimates of 95% reference and confidence intervals were calculated for each parameter. P = 0.05 was set as the threshold for statistical significance. Volunteers were classified using the Roussouly morphometric classification system. RESULTS: Respective means for the above-listed variables were: CL -10.04, TK 30.14, T1SPi -6.5, L1-L4 -12.45, L4-S1 -46.16, CTPA 2.5, TPA 4.65, PT 11.22, PI 48.04, LL -59. 10, PI-LL -11.11, C7 SVA mm -23.68. Plus/minus two standard deviations (SD) for the variables were: CL (-33.26, 13.12); TK (17.15, 43.30); T1SPi (-11.78, -1.25), L1-L4 (-25.55, 0.25), L4-S1 (-64.44, -27.55), CTPA (0.33, 4.80), TPA (-8.64, 18.22), PT (-1.99, 24.75), PI (25.23, 71.44), LL (-78.74, -39.89), PI-LL (-29.10, 7.04), and C7 SVA mm (-79.45, 32.08). CONCLUSIONS: In this prospective series of 100 adult volunteers, normal values for spinal and pelvic sagittal parameters were determined in Argentinian adults.

[Post-op paraspinal atrophy: Does the approach matter?] / Atrofia paraespinal postoperatoria. ¿El abordaje importa?

OBJECTIVE: To compare the level of post-op muscle atrophy related to the different approaches used in segmental lumbar fusion for degenerative disease (midline vs. Wiltse vs. MIS TLIF). MATERIALS AND METHODS: An observational, cross sectional, multicenter, descriptive and retrospective study was performed including a series of patients undergoing surgery for lumbar degenerative disease. We analyzed 45 patients (24 females), with a mean age of 58.7 years, undergoing surgery in 5 surgical centers between 2015 and 2018. A one-level instrumented fusion, from L3 to S1 was performed (7 cases L3-L4, 25 cases L4-L5 and 13 cases L5-S1). In 15 cases, a midline approach was used; in 15, a Wiltse approach was used, and in 15 cases, an MIS TLIF approach was used. All the patients were studied preoperatively and for at least 6 months after surgery (mean follow-up 14.6 months) with magnetic resonance imaging. The images were analyzed by three specialists in spine surgery. Two variables were considered to compare the level of atrophy before and after surgery: cross-sectional area (CSA) of the multifidus muscle (MM) and spinal erector muscles (SEM) and the fat infiltration level (FI) using the Kjaer visual classification. The analyses were conducted using the RStudio (1.1.383 version) statistical software, and the P values obtained were compared using the Wilcoxon rank-sum test. RESULTS: No significant differences were found between the approaches in terms of MM atrophy. The comparison of P for CSA and the SEM evidenced differences between MIS TLIF versus midline (P = 0.018) and midline versus Wiltse (P = 0.027). CONCLUSION: The minimally invasive approaches used for decompression and lumbar monosegmental arthrodesis had more impact on the EMs than on the MM. Randomized controlled trials might be useful to validate the results of this investigation.

[Trajectory of lumbar and sacral pedicular screws: Comparison between midline versus wiltse approach]. / Trayectoria de los tornillos pediculares lumbares y sacros: Comparación entre el abordaje por linea media versus el abordaje posterolateral tipo wiltse.

OBJECTIVES: To compare the posterolateral Wiltse approach and conventional Midline approach in short lumbosacral fusions in terms of the angle of convergence of pedicle screws. METHODS: We retrospectively reviewed computed tomography (CT) images of 76 lumbar and sacral pedicular screws that had been placed using a conventional midline approach (CA) (n = 38) and a Wiltse posterolateral approach (WA) (n = 38). All patients underwent short lumbosacral fusions from L3 to S1 for degenerative spinal disease. Screws with a bone gap >4 mm in any direction, cases with previous pedicular implants, and those with coronal plane curves >20° were excluded. RESULTS: Considering all implants, the angle of convergence was 23.3° (±15.8). The mean angulation in the WA group was 29.3° (±9.7), whereas in the CA group it was 17.2° (±0.6). This difference was statistically significant (P < 0.05). CONCLUSIONS: In short, lumbosacral fusion employing the Wiltse approach allowed placement of pedicle implants with more convergence than the conventional midline approach. The clinical relevance of this is unknown, and prospective randomized studies are needed to clarify this.