Mazda Farshad

• Prof. Dr. med, MPH
• Chair at Balgrist University Hospital

Introduction Degenerative changes in the lumbar spine may affect many structures, among them the intervertebral discs and the facet joints. The individual load distribution within the spine linked to posture and mass distribution is a probable cause of disease. This study had a dual aim: first, to systematically summarize previously reported associ...

One of the most established approaches to navigate pedicle screws is the planning and alignment (PA) method. Thereby a trajectory and associated entry point (EP) is planned and navigated after referencing to patient anatomy. However, deviations from the planned EP potentially lead to an altered screw position. The aim of this study was to investiga...

Optical 3D surface scanning has emerged as a valuable modality for assessing spinal deformity in patients with scoliosis, avoiding radiation exposure. However, correlations remain moderate between deformation parameters obtained from radiographs and those estimated solely from the 3D back surface, referred to as the “back-shape-to-spine” approach....

Purpose Augmented reality (AR) can generate realistic holograms overlaid on the real-word environment to provide an interactive learning experience. However, further research is needed to assess the impact of such technologies on knowledge acquisition. This study aims to evaluate the efficacy of an AR learning application in anatomy education. Met...

Background The results of rotator cuff (RC) repair surgery can be influenced by the presence of muscle atrophy and fatty infiltration. Three-dimensional (3D) quantitative data regarding those degenerative muscle changes after successful or failed RC repair are rare in the current literature. Hypothesis/Purpose The purpose of this study was to anal...

Purpose Semi-rigid spinal stabilization has been explored as an alternative to spinal fusion, and early experience with spinal segment augementation (“vertebropexy”) is promising. The main technical challenge is to maintain the integrity of the spinous processes during loading. This study aimed to compare different looping materials and techniques...

Background context Prehabilitation before spinal surgery may enhance patients’ ability to withstand physical and mental stress during the perioperative period. It has the potential to reduce complications, accelerate recovery, and deliver sustainable, patient-relevant improvements. However, high-quality evidence remains limited, and it is unclear w...

Background During full flexion of the spine, the paraspinal muscles are largely inactive. This suggests that passive structures like the posterior osteoligamentous complex (POLC), consisting of interspinous and supraspinous ligaments and the spinous processes, play a key role in spinal stability and protection of the spinal column. The POLC, howeve...

Introduction In patients with acute spinal cord injury (SCI) and degenerative cervical myelopathy (DCM), spinal cord compression is considered a main contributor to spinal cord damage, associated with cerebrospinal fluid (CSF) space obstruction. CSF pressure (CSFP) dynamics are studied as a potential indirect biomechanical marker for spinal cord co...

Background Blinding is essential for mitigating biases in trials of low back pain (LBP). Our main objectives were to assess the feasibility of blinding: (1) participants randomly allocated to active or placebo spinal manual therapy (SMT), and (2) outcome assessors. We also explored blinding by levels of SMT lifetime experience and recent LBP, and f...

To demonstrate the preoperative workup, surgical planning and execution of transforaminal endoscopic thoracic discectomy (TETD) for a giant calcified disc herniation. Surgeries for symptomatic thoracic disc herniations are rare and challenging. The main goal is to achieve sufficient decompression with minimal manipulation of the spinal cord. Conven...

Background Magnetic resonance imaging may suggest spinal cord compression and structural lesions in degenerative cervical myelopathy (DCM) but cannot reveal functional impairments in spinal pathways. We aimed to assess the value of contact heat evoked potentials (CHEPs) in addition to MRI and hypothesized that abnormal CHEPs may be evident in DCM i...

Category Ankle; Sports Introduction/Purpose Several demographical and clinical risk factors for recurrent ankle instability have been described. The main objective of this study was to investigate the potential influence of morphological characteristics of the ankle joint on the occurrence of recurrent instability and the functional outcomes follo...

Artificial intelligence (AI) is an aspiring new technology that bears a vast number of possibilities to facilitate patients’ care and to revolutionize current medical care. Especially in the complex field of spine surgery, in which treatment depends on a large number of variables, AI finds growing interest. The use of AI in spine surgery can be sub...

The current clinical gold standard to assess the condition and detect loosening of pedicle screw implants is radiation-emitting medical imaging. However, solely based on medical imaging, clinicians are not able to reliably identify loose implants in a substantial amount of cases. To complement medical imaging for pedicle screw loosening detection,...

Background With the increasing number of surgeries utilizing spinal instrumentation, three-dimensional surgical navigation aims to improve the accuracy of implant placement. However, its widespread clinical adaption has been hindered by factors such as high radiation exposure and interference with standard surgical workflows. Methods X23D is a nov...

Introduction Accurate landmark detection is essential for precise analysis of anatomical structures, supporting diagnosis, treatment planning, and monitoring in patients with spinal deformities. Conventional methods rely on laborious landmark identification by medical experts, which motivates automation. The proposed deep learning pipeline processe...

Study design Heterogeneous data collection via a mix of prospective, retrospective, and ambispective methods. Objective To evaluate the effect of biological sex on patient-reported outcomes after spinal fusion surgery for lumbar degenerative disease. Summary of Background Data Current literature suggests sex differences regarding clinical outcome...

Objective: Endoscopic spine surgery is an emerging technique of minimally invasive spine surgery. However, headache, seizure, and autonomic dysreflexia are possible irrigation-related complications following full-endoscopic lumbar discectomy (FELD). Pressure elevation through fluid irrigation may contribute to these adverse events. A validated expe...

Purpose The value of adding fusion to decompression surgery for lumbar degenerative spondylolisthesis and spinal canal stenosis remains debated. Therefore, the comparative effectiveness and selected healthcare resource utilization of patients undergoing decompression with or without fusion surgery at 3 years follow-up was assessed. Methods Using o...

Study Design This was a single-center prospective clinical and radiographic analysis of pedicle screw instrumentation with Robotic-assisted navigation (RAN) and augmented reality (AR). Objective This study aimed to compare the accuracy of lumbosacral pedicle screw placement with RAN versus AR. Summary of Background Data RAN and AR have demonstrat...

Introduction: The vertebral cartilage endplate (CEP), crucial for intervertebral disc health, is prone to degeneration linked to chronic low back pain, disc degeneration, and Modic changes (MC). While it is known that disc cells express toll-like receptors (TLRs) that recognize pathogen- and damage-associated molecular patterns (PAMPs and DAMPs), i...

Introduction Modic changes (MC) are bone marrow lesions of vertebral bones, which can be detected with magnetic resonance imaging (MRI) adjacent to degenerated intervertebral discs. Defined by their appearance on T1 and T2 weighted images, there are three interconvertible types: MC1, MC2, and MC3. The inter‐observer variability of the MRI diagnosis...

Background Clinical prediction models (CPM), such as the SCOAP-CERTAIN tool, can be utilized to enhance decision-making for lumbar spinal fusion surgery by providing quantitative estimates of outcomes, aiding surgeons in assessing potential benefits and risks for each individual patient. External validation is crucial in CPM to assess generalizabil...

Background: Anterior cervical discectomy and fusion (ACDF) for the surgical treatment of cervical degenerative disease often includes an intervertebral cage, which restores disc height and lordosis while promoting fusion . Cage materials include titanium (TTN) or polyetheretherketone (PEEK). Controversy in material selection stems from higher fusi...

Introduction New diagnostic techniques are a substantial research focus in degenerative cervical myelopathy (DCM). This cross-sectional study determined the significance of cardiac-related spinal cord motion and the extent of spinal stenosis as indicators of mechanical strain on the cord. Methods Eighty-four DCM patients underwent MRI/clinical ass...

Background Modic type 1 changes (MC1) are changes of vertebral bone marrow signal intensity found predominantly in patients with degenerated intervertebral discs and damaged cartilage endplates. Discs adjacent to MC1 (MC1 discs) degenerate faster and release more pro-inflammatory and pro-fibrotic factors compared to other degenerated discs. Yet, it...

Background Modic type 1 changes (MC1) are signal intensity changes on magnetic resonance imaging (MRI) associated with vertebrogenic pain. Endplate damage is associated with MC1, exposing immune-privileged disc tissue to the immune cells from adjacent bone marrow. Despite many studies pointing on the role of inflammation in MC1, a comprehensive inv...

Background Cervical posterior instrumentation and fusion is often performed to avoid post-laminectomy kyphosis. However, larger comparative analyses of cervical laminectomy with or without fusion are sparse. Methods A retrospective, two-center, comparative cohort study included patients after stand-alone dorsal laminectomy with (n = 91) or without...

Introduction The vertebral cartilage endplate (CEP), essential for intervertebral disc health, is susceptible to degeneration, which can be associated with chronic low back pain, disc degeneration, and Modic changes. Although it has been established that intervertebral disc cells express toll-like receptors (TLRs), which can recognize diverse patho...

Purpose To analyze the effect of endplate weakness prior to PLIF or TLIF cage implantation and compare it to the opposite intact endplate of the same vertebral body. In addition, the influence of bone quality on endplate resistance was investigated. Methods Twenty-two human lumbar vertebrae were tested in a ramp-to-failure test. One endplate of ea...

Introduction The emerging field of the disc microbiome challenges traditional views of disc sterility, which opens new avenues for novel clinical insights. However, the lack of methodological consensus in disc microbiome studies introduces discrepancies. The aims of this study were to (1) compare the disc microbiome of non‐Modic (nonMC), Modic type...

Purpose Hypoplastic pedicles of the thoracolumbar spine (<5 mm diameter) are often found in syndromic deformities of the spine and pose a challenge in pedicle screw instrumentation. 3D-printed patient-specific guides might help overcome anatomical difficulties when instrumenting pedicles with screws, thereby reducing the necessity for less effectiv...

Objectives Modic type 1 changes (MC1) are vertebral endplate bone marrow (BM) lesions observed on magnetic resonance images in sub-populations of chronic low back pain (CLBP) patients. The etiopathogenesis remains unknown and treatments that modify the underlying pathomechanisms do not exist. We hypothesized that two biological MC1 subtypes exist:...

Background Several demographic and clinical risk factors for recurrent ankle instability have been described. The main objective of this study was to investigate the potential influence of morphologic characteristics of the ankle joint on the occurrence of recurrent instability and the functional outcomes following a modified Broström-Gould procedu...

Background The perioperative antibiotic prophylaxis with 1st or 2nd generation cephalosporins is evidence-based in orthopedic surgery. There are, however, situations with a high risk of prophylaxis-resistant surgical site infections (SSI). Methods We perform a superiority randomized controlled trial with a 10% margin and a power of 90% in favor of...

Introduction: Pedicle screw loosening is a major problem in spine surgery. Computed tomography (CT) is the gold standard to diagnose screw loosening. Disadvantages of CT include low sensitivity and specificity for the detection of loosened screws as well as the need for radiation exposure. The aim of this study was to provide a proof of concept of...

Introduction The periacetabular osteotomy is a technically demanding procedure with the goal to improve the osseous containment of the femoral head. The options for controlled execution of the osteotomies and verification of the acetabular reorientation are limited. With the assistance of augmented reality, new possibilities are emerging to guide t...

The aim of this study was to determine tissue-specific blood perfusion impairment of the cervical cord above the compression site in patients with degenerative cervical myelopathy (DCM) using intravoxel incoherent motion (IVIM) imaging. A quantitative MRI protocol, including structural and IVIM imaging, was conducted in healthy controls and patient...

This study evaluates potential associations between the perioperative urinary catheter (UC) carriage and (Gram-negative) surgical site infections (SSIs) after spine surgery. It is a retrospective, single-center, case-control study stratifying group comparisons, case-mix adjustments using multivariate logistic regression analyses. Around half of the...

Introduction Degenerative cervical myelopathy (DCM) is the most common cause of non-traumatic incomplete spinal cord injury, but its pathophysiology is poorly understood. As spinal cord compression observed in standard MRI often fails to explain a patient's status, new diagnostic techniques to assess DCM are one of the research priorities. Minor ca...

Study Design Biomechanical cadaveric study. Objective The goal of this study was to analyze the effects of an endoscopic transpedicular approach with different drill diameters (6 and 8 mm) to compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle was investigated. Summary of Backgroun...

Case Three patients with low-grade spondylolisthesis were treated with vertebropexy, a new surgical technique that replaces rigid fusion with ligamentous stabilization. Clinical outcomes, functional radiographs, and magnetic resonance imaging were used to document the early clinical results of this biomechanically established and promising new surg...

Background Lumbar spine pathology (LSP) is a common source of low back or leg pain, and paraspinal muscle in these patients demonstrates fatty and fibrotic infiltration, and cellular degeneration that do not reverse with exercise-based rehabilitation. However, it is unclear of this lack of response is due to insufficient exercise stimulus, or an i...

Background: Spinal fusion is the most common surgical treatment for the management of degenerative spinal disease. However, complications such as screw loosening lead to painful pseudoarthrosis, and are a common reason for revision. Optimization of screw trajectories to increase implant resistance to mechanical loading is essential. A recent optimi...

The pain in patients with Modic type 1 changes (MC1) is often due to vertebral body endplate pain, which is linked to abnormal neurite outgrowth in the vertebral body and adjacent endplate. The aim of this study was to understand the role of MC1 bone marrow stromal cells (BMSCs) in neurite outgrowth. BMSCs can produce neurotrophic factors, which ha...

Purpose: Spinal instrumentation with pedicle screw placement (PSP) is an important surgical technique for spinal diseases. Accurate screw trajectory is a prerequisite for PSP. Ultrasound (US) imaging with robot-assisted system forms a non-radiative alternative to provide precise screw trajectory. This study reports on the development and assessmen...

Objective To compare the image quality of low-dose CT (LD-CT) with tin filtration of the lumbar spine after metal implants to standard clinical CT, and to evaluate the potential for metal artifact and dose reduction. Materials and methods CT protocols were optimized in a cadaver torso. Seventy-four prospectively included patients with metallic lum...

Background Pseudoarthrosis after anterior cervical discectomy and fusion (ACDF) is relatively common and can result in revision surgery. The aim of the study was to analyze the outcome of patients who underwent anterior revision surgery for pseudoarthrosis after ACDF. Methods From 99 patients with cervical revision surgery, ten patients (median ag...

The aim of this study was to determine tissue-specific blood perfusion impairment of the cervical cord above the compression site in patients with degenerative cervical myelopathy (DCM) using intravoxel incoherent motion (IVIM) imaging. A quantitative MRI protocol, including structural and IVIM imaging, was conducted in healthy controls and patient...

Purpose Over the last years, interest and efforts to implement augmented reality (AR) in orthopedic surgery through head-mounted devices (HMD) have increased. However, the majority of experiments were preclinical and within a controlled laboratory environment. The operating room (OR) is a more challenging environment with various confounding factor...

Established surgical navigation systems for pedicle screw placement have been proven to be accurate, but still reveal limitations in registration or surgical guidance. Registration of preoperative data to the intraoperative anatomy remains a time-consuming, error-prone task that includes exposure to harmful radiation. Surgical guidance through conv...

Background: Spine biomechanics is a field of applied research aiming to unravel the biomechanical understanding of the spine and its disorders and to understand the implications of their interventional therapy to improve clinical practice, physical performance and daily living. Its scientific whereabouts can be traced in the work of Aristotle, who...

Background context: Posterior decompression with spinal instrumentation and fusion is associated with well-known complications. Alternatives that include decompression and restoration of native stability of the motion segment without fusion continue to be explored, however, an ideal solution has yet to be identified. Purpose: The aim of this stu...

Purpose To develop and test synthetic vertebral stabilization techniques (“vertebropexy”) that can be used after decompression surgery and furthermore to compare them with a standard dorsal fusion procedure. Methods Twelve spinal segments (Th12/L1: 4, L2/3: 4, L4/5: 4) were tested in a stepwise surgical decompression and stabilization study. Stabi...

Background Modic changes (MC) are painful vertebral bone marrow lesions and are often found in patients with chronic low back pain. The adjacent intervertebral disc (IVD) seems to play an important role: the rapidly degrading disc stands in an inflammatory cross-talk with the MC bone marrow and MC develop almost always simultaneously cranial and ca...

Background Modic type 1 changes (MC1) are painful vertebral bone marrow lesions often found in patients with chronic low back pain. Damage of the endplate associates with MC1, is a risk factor for MC1 progression, and associates with pain. Recent evidence suggests a role of MC bone marrow neutrophils in endplate damage. Objectives The aim of this...

Background Vertebral bone marrow lesions known as Modic type 1 changes (MC1) are a major contributor to unspecific lower back pain. Pain may relate to the higher innervation of MC1 endplates. Blocking neo-innervation in MC1 could be a promising treatment approach for MC1. Bone marrow stromal cells (BMSC) can produce neurotrophic factors and are dys...

Background Modic type 1 changes (MC1) are painful vertebral bone marrow (BM) edema of unclear etiology. Besides mechanical aspects, animal studies show the plausibility for two biological etiologies. In the bacterial etiology, Cutibacterium acnes ( C. acnes ) invades damaged intervertebral discs (IVDs) resulting in IVD infection and endplate damage...

Purpose: Robot-assisted ultrasound (rUS) systems have already been used to provide non-radiative three-dimensional (3D) reconstructions that form the basis for guiding spine surgical procedures. Despite promising studies on this technology, there are few studies that offer insight into the robustness and generality of the approach by verifying per...

Spinal fusion surgery requires highly accurate implantation of pedicle screw implants, which must be conducted in critical proximity to vital structures with a limited view of anatomy. Robotic surgery systems have been proposed to improve placement accuracy, however, state-of-the-art systems suffer from the limitations of open-loop approaches, as t...

State-of-the-art research of traditional computer vision is increasingly leveraged in the surgical domain. A particular focus in computer-assisted surgery is to replace marker-based tracking systems for instrument localization with pure image-based 6DoF pose estimation. However, the state of the art has not yet met the accuracy required for surgica...

Purpose The aim of this study was to elucidate segmental range of motion (ROM) before and after common decompression and fusion procedures on the lumbar spine. Methods ROM of fourteen fresh-frozen human cadaver lumbar segments (L1/2: 4, L3/4: 5, L5/S1: 5) was evaluated in six loading directions: flexion/extension (FE), lateral bending (LB), latera...

Despite the undeniable advantages of image-guided surgical assistance systems in terms of accuracy, such systems have not yet fully met surgeons' needs or expectations regarding usability, time efficiency, and their integration into the surgical workflow. On the other hand, perceptual studies have shown that presenting independent but causally corr...

In the flexed end-of-range position (e.g., during slumped sitting), the trunk is passively stabilized. Little is known about the biomechanical consequence of posterior approaches on passive stabilization. The aim of this study is to investigate the effect of posterior surgical interventions on local and distant spinal regions. While being fixed at...

Pedicle drilling is a complex and critical spinal surgery task. Detecting breach or penetration of the surgical tool to the cortical wall during pilot-hole drilling is essential to avoid damage to vital anatomical structures adjacent to the pedicle, such as the spinal cord, blood vessels, and nerves. Currently, the guidance of pedicle drilling is d...

Background The preoperative body surface and nasal decolonization may reduce the risk of surgical site infections (SSI), but yields conflicting results in the current orthopedic literature. Methods We perform a single-center, randomized-controlled, superiority trial in favor of the preoperative decolonization using a commercial product (octenidin®...

Purpose To develop ligamentous vertebral stabilization techniques (“vertebropexy”) that can be used after microsurgical decompression (intact posterior structures) and midline decompression (removed posterior structures) and to elaborate their biomechanical characteristics. Methods Fifteen spinal segments were biomechanically tested in a stepwise...

Purpose To compare the residual range of motion (ROM) of cortical screw (CS) versus pedicle screw (PS) instrumented lumbar segments and the additional effect of transforaminal interbody fusion (TLIF) and cross-link (CL) augmentation. Methods ROM of thirty-five human cadaver lumbar segments in flexion/extension (FE), lateral bending (LB), lateral s...

Purpose To elucidate residual motion of cortical screw (CS) and pedicle screw (PS) constructs with unilateral posterior lumbar interbody fusion (ul-PLIF), bilateral PLIF (bl-PLIF), facet-sparing transforaminal lumbar interbody fusion (fs-TLIF), and facet-resecting TLIF (fr-TLIF). Methods A total of 35 human cadaver lumbar segments were instrumente...