High Prevalence of Work-related Musculoskeletal Disorders and Limited Evidence-based Ergonomics in Orthopaedic Surgery: A Systematic Review.

BACKGROUND: The Centers for Disease Control defines work-related musculoskeletal disorders as disorders of the nerves, muscles, tendons, joints, spinal discs, and cartilage that are caused or exacerbated by the environment or nature of work. Previous meta-analyses have characterized work-related musculoskeletal disorders among interventionists, general surgeons, and other surgical subspecialties, but prevalence estimates, prognosis, and ergonomic considerations vary by study and surgical specialty. QUESTIONS/PURPOSES: (1) What is the career prevalence of work-related musculoskeletal disorders in orthopaedic surgeons? (2) What is the treatment prevalence associated with work-related musculoskeletal disorders in orthopaedic surgeons? (3) What is the disability burden of work-related musculoskeletal disorders in orthopaedic surgeons? (4) What is the scope of orthopaedic surgical ergonomic assessments and interventions? METHODS: A systematic review of English-language studies from PubMed, MEDLINE, Embase, and Scopus was performed in December 2022 and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies that presented prevalence estimates of work-related musculoskeletal disorders or assessed surgical ergonomics in orthopaedic surgery were included. Reviews, case reports, gray literature (conference abstracts and preprints), and studies with mixed-surgeon (nonorthopaedic) populations were excluded. The search yielded 5603 abstracts; 24 survey-based studies with 4876 orthopaedic surgeons (mean age 48 years; 79% of surgeons were men) were included for an analysis of work-related musculoskeletal disorders, and 18 articles were included for a descriptive synthesis of ergonomic assessment. Quality assessment using the Joanna Briggs Institute Tool revealed that studies had a low to moderate risk of bias, largely because of self-reporting survey-based methodology. Because of considerable heterogeneity and risk of bias, prevalence outcomes were not pooled and instead are presented as ranges (mean I 2 = 91.3%). RESULTS: The career prevalence of work-related musculoskeletal disorders in orthopaedic surgeons ranged from 37% to 97%. By anatomic location, the prevalence of work-related musculoskeletal disorders in the head and neck ranged from 4% to 74%; back ranged from 9% to 77%; forearm, wrist, and hand ranged from 12% to 54%; elbow ranged from 3% to 28%; shoulder ranged from 3% to 34%; hip and thigh ranged from 1% to 10%; knee and lower leg ranged from 1% to 31%; and foot and ankle ranged from 4% to 25%. Of orthopaedic surgeons reporting work-related musculoskeletal disorders, 9% to 33% had a leave of absence, practice restriction or modification, or early retirement, and 27% to 83% received some form of treatment. Orthopaedic surgeons experienced biomechanical, cardiovascular, neuromuscular, and metabolic stress during procedures. Interventions to improve orthopaedic surgical ergonomics have been limited, but have included robotic assistance, proper visualization aids, appropriate use of power tools, and safely minimizing lead apron use. In hip and knee arthroplasty, robotic assistance was the most effective in improving posture and reducing caloric expenditure. In spine surgery, proper use of surgical loupes was the most effective in improving posture. CONCLUSION: Although the reported ranges of our main findings were wide, even on the low end of the reported ranges, work-related musculoskeletal disability among orthopaedic surgeons appears to be a substantial concern. We recommend that orthopaedic residency training programs incorporate surgical ergonomics or work injury lectures, workshops, and film review (alongside existing film review of surgical skills) into their curricula. We suggest hospitals engage in shared decision-making with surgeons through anonymous needs assessment surveys to implement wellness programs specific to surgeons' musculoskeletal needs. We urge institutions to assess surgeon ergonomics during routine quality assessment of novel surgical instruments and workflows. LEVEL OF EVIDENCE: Level III, prognostic study.

Metal-Free Cortico-Pedicular Device for Supplemental Fixation in Lumbar Interbody Fusion.

OBJECTIVE: Pedicle screw fixation is a commonly utilized adjunct for lumbar interbody fusion, yet risks include screw malposition, pullout, loosening, neurovascular injury, and stress transfers leading to adjacent segment degeneration. This report describes the preclinical and initial clinical results of a minimally invasive, metal-free cortico-pedicular fixation device used for supplemental posterior fixation in lumbar interbody fusion. METHODS: Safety of arcuate tunnel creation was evaluated in cadaveric lumbar (L1-S1) specimens. A finite element analysis study evaluated clinical stability of the device to pedicular screw-rod fixation at L4-L5. Preliminary clinical results were assessed by analysis of Manufacturer and User Facility Device Experience database complications, and 6-month outcomes in 13 patients treated with the device. RESULTS: Among 35 curved drill holes in 5 lumbar specimens, no breaches of the anterior cortex were identified. The mean minimum distance from the anterior surface of the hole to the spinal canal ranged from 5.1 mm at L1-L2 to 9.8 mm at L5-S1. In the finite element analysis study, the polyetheretherketone strap provided comparable clinical stability and reduced anterior stress shielding compared to the conventional screw-rod construct. The Manufacturer and User Facility Device Experience database identified 1 device fracture with no clinical sequelae among 227 procedures. Initial clinical experience showed a 53% decrease in pain severity (P = 0.009), a 50% decrease in Oswestry Disability Index (P < 0.001), and no device-related complications. CONCLUSIONS: Cortico-pedicular fixation is a safe and reproducible procedure that may address limitations of pedicle screw fixation. Longer term clinical data in large clinical studies are recommended to confirm these promising early results.

Finite element analysis comparing a PEEK posterior fixation device versus pedicle screws for lumbar fusion.

BACKGROUND: Pedicle screw loosening and breakage are common causes of revision surgery after lumbar fusion. Thus, there remains a continued need for supplemental fixation options that offer immediate stability without the associated failure modes. This finite element analysis compared the biomechanical properties of a novel cortico-pedicular posterior fixation (CPPF) device with those of a conventional pedicle screw system (PSS). METHODS: The CPPF device is a polyetheretherketone strap providing circumferential cortical fixation for lumbar fusion procedures via an arcuate tunnel. Using a validated finite element model, we compared the stability and load transfer characteristics of CPPF to intact conditions under a 415 N follower load and PSS conditions under a 222 N preload. Depending on the instrumented levels, two different interbody devices were used: a lateral lumbar interbody device at L4-5 or an anterior lumbar interbody device at L5-S1. Primary outcomes included range of motion of the functional spinal units and anterior load transfer, defined as the total load through the disk and interbody device after functional motion and follower load application. RESULTS: Across all combinations of interbody devices and lumbar levels evaluated, CPPF consistently demonstrated significant reductions in flexion (ranging from 90 to 98%), extension (ranging from 88 to 94%), lateral bending (ranging from 75 to 80%), and torsion (ranging from 77 to 86%) compared to the intact spine. Stability provided by the CPPF device was comparable to PSS in all simulations (range of motion within 0.5 degrees for flexion-extension, 0.6 degrees for lateral bending, and 0.5 degrees for torsion). The total anterior load transfer was higher with CPPF versus PSS, with differences across all tested conditions ranging from 128 to 258 N during flexion, 89-323 N during extension, 135-377 N during lateral bending, 95-258 N during torsion, and 82-250 N during standing. CONCLUSION: Under the modeled conditions, cortico-pedicular fixation for supplementing anterior or lateral interbody devices between L4 and S1 resulted in comparable stability based on range of motion measures and less anterior column stress shielding based on total anterior load transfer measures compared to PSS. Clinical studies are needed to confirm these finite element analysis findings.

Ninety-day complication, revision, and readmission rates for current-generation robot-assisted thoracolumbar spinal fusion surgery: results of a multicenter case series.

OBJECTIVE: Robotics is a major area for research and development in spine surgery. The high accuracy of robot-assisted placement of thoracolumbar pedicle screws is documented in the literature. The authors present the largest case series to date evaluating 90-day complication, revision, and readmission rates for robot-assisted spine surgery using the current generation of robotic guidance systems. METHODS: An analysis of a retrospective, multicenter database of open and minimally invasive thoracolumbar instrumented fusion surgeries using the Mazor X or Mazor X Stealth Edition robotic guidance systems was performed. Patients 18 years of age or older and undergoing primary or revision surgery for degenerative spinal conditions were included. Descriptive statistics were used to calculate rates of malpositioned screws requiring revision, as well as overall complication, revision, and readmission rates within 90 days. RESULTS: In total, 799 surgical cases (Mazor X: 48.81%; Mazor X Stealth Edition: 51.19%) were evaluated, involving robot-assisted placement of 4838 pedicle screws. The overall intraoperative complication rate was 3.13%. No intraoperative implant-related complications were encountered. Postoperatively, 129 patients suffered a total of 146 complications by 90 days, representing an incidence of 16.1%. The rate of an unrecognized malpositioned screw resulting in a new postoperative radiculopathy requiring revision surgery was 0.63% (5 cases). Medical and pain-related complications unrelated to hardware placement accounted for the bulk of postoperative complications within 90 days. The overall surgical revision rate at 90 days was 6.63% with 7 implant-related revisions, representing an implant-related revision rate of 0.88%. The 90-day readmission rate was 7.13% with 2 implant-related readmissions, representing an implant-related readmission rate of 0.25% of cases. CONCLUSIONS: The results of this multicenter case series and literature review suggest current-generation robotic guidance systems are associated with low rates of intraoperative and postoperative implant-related complications, revisions, and readmissions at 90 days. Future outcomes-based studies are necessary to evaluate complication, revision, and readmission rates compared to conventional surgery.

Central cord syndrome.

Central cord syndrome is the most common type of incomplete spinal cord injury. This syndrome most often occurs in older persons with underlying cervical spondylosis caused by a hyperextension mechanism. It also occurs in younger persons who sustain trauma to the cervical spine and, less commonly, as a result of nontraumatic causes. The upper extremities are more affected than the lower extremities, with motor function more severely impaired than sensory function. Central cord syndrome presents a spectrum, from weakness limited to the hands and forearms with sensory preservation, to compete quadriparesis with sacral sparing as the only evidence of incomplete spinal cord injury. Historically, treatment has been nonsurgical, but recovery is often incomplete. Early surgical treatment of central cord syndrome remains controversial. However, recent studies have shown benefits, particularly of early surgery to decompress the spinal cord in patients with pathologic conditions revealed by radiography or MRI.

Acute cervical osteomyelitis and prevertebral abscess after routine tonsillectomy.

BACKGROUND CONTEXT: Tonsillectomy is among the most commonly performed surgical procedures. The development of severe infection after tonsillectomy is a very rare but potentially fatal complication that has not been described in the orthopedic, neurosurgical, or spine literature. PURPOSE: To present acute cervical osteomyelitis and prevertebral abscess formation as a complication of a routine tonsillectomy. STUDY DESIGN: Case report, literature review. METHODS: A case report was prepared on the clinical and radiographic data of a patient presenting with prevertebral abscess and acute cervical osteomyelitis 6 weeks after routine tonsillectomy. A review of relevant literature was additionally performed. RESULTS: The patient presented 6 weeks after tonsillectomy with evidence of a deep cervical infection. Operative debridement with anterior and posterior surgical stabilization was performed. The patient completed a 6-week course of intravenous antibiotics. At 24-month follow-up, the patient showed no signs of infection and demonstrated a stable fusion mass. CONCLUSIONS: The development of prevertebral abscess and acute cervical osteomyelitis has been discussed in a small number of otolaryngology case reports and has not been previously reported in the orthopedic, neurosurgical, or spine literature. Symptoms may be nonspecific, and so a high index of clinical suspicion is needed. Delay in treatment may lead to significant morbidity and even mortality. Successful treatment can be obtained through operative debridement and intravenous antibiotic therapy.

Degenerative cervical spondylosis: clinical syndromes, pathogenesis, and management.

Degenerative changes in the cervical spinal column are ubiquitous in the adult population, but infrequently symptomatic. The evaluation of patients with symptoms is facilitated by classifying the resulting clinical syndromes into axial neck pain, cervical radiculopathy, cervical myelopathy, or a combination of these conditions. Although most patients with axial neck pain, cervical radiculopathy, or mild cervical myelopathy respond well to initial nonsurgical treatment, those who continue to have symptoms or patients with clinically evident myelopathy are candidates for surgical intervention.

The meniscal ossicle revisited: etiology and an arthroscopic technique for treatment.

We describe a new arthroscopic technique for repair of meniscal ossicles in support of the theory that meniscal ossicles are traumatic in nature. Using a standard inferolateral portal, the arthroscope is passed under the posterior cruciate ligament to permit visualization of the "root" of the medial meniscus with a matching donor lesion on the tibia. A limited debridement should be performed of the donor site as well as the posterior horn of the meniscus if it has healed over with fibrocartilage to allow bone-to-bone healing. A posteromedial working portal is made at an angle amenable to the repair and a 6-mm cannula is placed. A Beath passing pin commonly used for anterior cruciate ligament reconstruction is used to pass suture for the outside-inside-out repair. The pin is passed through the cannula in the posterior medial portal. The root of the medial meniscus and the avulsed ossicle are pierced with the Beath pin and tensioned, after which the pin is drilled into the matching donor site and out through the tibia. Two passes are used to create a mattress suture through the ossicle, and the suture is tied over a bone bridge on the anterolateral tibia.

Acute hip pain in the nonambulatory infant: Salter-Harris type I fracture in the capital femoral epiphysis without a traumatic history.

An otherwise healthy 11-month-old girl was brought to the hospital after her parents noted the acute onset of right hip pain and refusal to bear weight. No abnormalities were seen in the initial radiographs, laboratory values were within reference range, and noninvasive workup was negative for septic arthritis. The parents reported a recent minor fall from a standing position, but stated that the child seemed to return to normal without pain after a few minutes of crying. A hemarthrosis without purulence was found upon joint aspiration, and the patient improved significantly after administration of anti-inflammatory medication. Follow-up radiographs 13 days after initial presentation showed an extremely rare Salter-Harris type I proximal physeal fracture well into the healing process.

Multiexpandable cage for minimally invasive posterior lumbar interbody fusion.

The increasing adoption of minimally invasive techniques for spine surgery in recent years has led to significant advancements in instrumentation for lumbar interbody fusion. Percutaneous pedicle screw fixation is now a mature technology, but the role of expandable cages is still evolving. The capability to deliver a multiexpandable interbody cage with a large footprint through a narrow surgical cannula represents a significant advancement in spinal surgery technology. The purpose of this report is to describe a multiexpandable lumbar interbody fusion cage, including implant characteristics, intended use, surgical technique, preclinical testing, and early clinical experience. Results to date suggest that the multiexpandable cage allows a less invasive approach to posterior/transforaminal lumbar interbody fusion surgery by minimizing iatrogenic risks associated with static or vertically expanding interbody prostheses while providing immediate vertebral height restoration, restoration of anatomic alignment, and excellent early-term clinical results.

A novel total knee arthroplasty infection model in rabbits.

Infection of biomaterial implants is an expensive and devastating complication of orthopaedic surgery historically ranging from less than 1% in primary total knee arthroplasty (TKA) to 10% in revision TKA. An in vivo animal model was developed to test the efficacy of innovative therapies for the prevention of biomaterial centered infections caused by methicillin-resistant Staphylococcus aureus bacteria (MRSA). Twenty-two New Zealand White rabbits were used in this study. After proper anesthesia, a stainless-steel screw with a high molecular weight polyethylene (UHMWPE) washer was cemented in a defect created in the intra-articular, non-articulating portion of the lateral femoral condyle of each knee. After closure of the joint capsule, each knee was inoculated with 0, 10(2), 10(3), or 10(4) colony forming units (CFU) of MRSA. Animals were sacrificed after 7 days at which time joint aspirate, tissues and biomaterial samples were examined for evidence of infection. A total of 42 knees were used for analysis. When saline was injected into the knee, 0/10 of the knees demonstrated evidence of biomaterial centered infection (with the contralateral knee receiving 10(4)CFU MRSA). Four of 10 knees developed a biomaterial centered infection when 10(2)CFU MRSA was introduced. Seven out of 10 knees developed a biomaterial centered infection when either 10(3) or 10(4)CFU MRSA was injected. No evidence of septicemia (positive blood cultures) was found in any animal. This rabbit knee model utilizes commonly employed inexpensive orthopaedic implant materials in an in vivo milieu and provides an effective method for the evaluation of treatments for biomaterial centered infections.

Supra-acetabular placement of external fixator pins: a safe and expedient method of providing the injured pelvis with stability.

Applying a stable anterior pelvic external fixator frame is a skill that should be mastered by all orthopedic surgeons who treat acutely injured patients. Splinting of an unstable pelvis during resuscitation can help to reduce the volume of the true pelvis, pending definitive surgical stabilization of the pelvic ring. Supra-acetabular pin placement, less familiar to most surgeons than iliac wing pin placement is, can provide a more reliable pin-bone interface and thus allow improved reduction ability with fewer soft-tissue complications. Because of their location, supra-acetabular pins also seem to be better tolerated than iliac crest pins when used for definitive management of the pelvic ring disruption. A young man who sustained a type II anteroposterior compression injury in a motor vehicle accident presented with symphyseal disruption (7 cm wide) and left anterior sacroiliac joint disruption. During resuscitation, the pelvis was anatomically reduced and stabilized with a supra-acetabular pin-based external fixator. Pin locations, chosen using palpable and cutaneous landmarks, were inserted without additional imaging guidance. The fracture was reduced anatomically, and the frame was used for definitive management of the pelvic ring injury.

Reduction of postoperative spinal implant infection using gentamicin microspheres.

STUDY DESIGN: Three noncontiguous spinal implant sites in 1 rabbit were challenged with Staphylococcus aureus and local antibiotic prophylaxis was given with gentamicin in controlled-release microspheres (poly(lactic-coglycolic-acid) [PLGA]). Postoperative biomaterial-centered infection on and around the titanium rods was assessed using standard bacterial quantification essays. OBJECTIVE: To assess surgical site and biomaterial-centered infection reduction with controlled release gentamicin from microspheres against S. aureus. SUMMARY OF BACKGROUND DATA: A postoperative biomaterial-centered infection can be devastating after successful thoracolumbar spinal surgery and puts a high burden on patients, families, surgeons, and hospitals, endangering both our healthcare budget and our ability to perform challenging cases in patients with increasing numbers of comorbidities. Systemic antibiotics often do not reach "dead-space" hematomas where bacteria harbor after surgery, whereas local, controlled release gentamicin prophylaxis through PLGA microspheres showed favorable pharmacokinetics data to achieve local bactericidal concentrations for up to 7 days after surgery. METHODS: A well published rabbit spinal implant model with systemic cephalosporin prophylaxis was challenged to create a baseline infection of approximately 70% in control sites. We then challenged 3 noncontiguous titanium rods inside the laminectomy defect with 10e6 colony forming units S. aureus and randomly treated 2 sites with gentamicin PLGA microspheres and 1 site with PLGA carrier only (control). Standard quantification techniques were used to assess biomaterial centered and soft tissue bacterial growth after 7 days. RESULTS: After establishing reliable infection rates in control sites, the therapeutic arm of the study was started. Surgical site infections were found in 75% of control sites, whereas gentamicin microspheres reduced the incidence down to 38% in the same rabbits. Biomaterial-centered infection was reduced from 58% to 23% only in all sites challenged with 10e6 S. aureus. CONCLUSION: Postoperative, biomaterial-centered infection was reduced at least 50% with intraoperative gentamicin microspheres in the face of systemic cephalosporin prophylaxis and high dose S. aureus in a laminectomy defect in rabbits. The data are statistically and clinically significant, and further animal testing is planned to confirm these results.

Minimally invasive posterior fixation.

Significant advances have been made in the contemporary management of thoracolumbar spinal deformities, including improved segmental bony fixation, techniques for osteotomy, and mechanically powerful reduction maneuvers, which now allow the spinal surgeon to correct severe, complex, and rigid spinal deformities. However, one of the major limitations of surgical intervention has been the high complication rates associated with these surgical endeavors. Much of the morbidity associated with posterior deformity surgery relates to the extensive soft tissue destruction necessary to gain access to multiple segments of the axial skeleton. The open exposures for long-segment fixation result in additional blood loss, increased rates of infection, and prolonged immobilization caused by postoperative pain. Minimally invasive techniques attempt to overcome these drawbacks of the open exposures, and this report reviews preliminary experience in treating spinal deformities with long-segment minimally invasive internal fixation.

Locally delivered polyclonal antibodies potentiate intravenous antibiotic efficacy against gram-negative infections.

PURPOSE: Comparison of the anti-microbial efficacy of locally delivered antibodies in tandem with conventional systemic administration of ceftazidime antibiotic therapy in two lethal gram-negative animal infection models. METHODS: Previously published lethal E. coli-induced closed peritonitis and Klebsiella-induced burn wound infections were generated in outbred female CF-1 mice cohorts. Pooled human polyclonal antibodies were injected locally into sites of infection in these mice simultaneously with intravenous infusions of the broad-spectrum antibiotic, ceftazidime. Mouse survival was compared in sham control cohorts vs. both ceftazidime-alone or antibody-alone systemically infused cohorts as well as local antibody-systemic ceftazidime combination therapy cohorts. Microbial burdens in blood and tissue samples (by agar plating), as well as interleukin-6 cytokine levels (using ELISA) correlated with sepsis, were monitored in sacrificed animals as a function of antimicrobial treatment regimen. RESULTS: Local delivery of human polyclonal antibodies to infection sites was shown to produce synergistic therapeutic efficacy in combination with systemic antibiotic administration in these lethal wound infection models in mice. Enhanced benefits of the unique combination therapy included host survival, bacterial burden both locally and systemically, and IL-6 levels in host serum. CONCLUSIONS: Commercial pooled human antibodies contain a broad spectrum of antimicrobial activity against gram-negative pathogens. Prevention of systemization of infection correlates with host survival in these models. Local control of infection using doses of local, high-titer polyclonal antibodies can enhance traditional approaches to curb systemic spread of infection using intravenous antibiotics. Antibodies provide antimicrobial efficacy independent of known pathogen resistance mechanisms.