In 2021 the bone grafting market was worth €2.72 billion globally. As allograft bone has a limited supply and risk of disease transmission, the demand for synthetic grafting substitutes (BGS) continues to grow while allograft bone grafts steadily decrease. Synthetic BGS are low in mechanical strength and bioactivity, inspiring the development of novel grafting materials, a traditionally laborious and expensive process. Here a novel BGS derived from sustainably grown coral was evaluated. Coral-derived scaffolds are a natural calcium carbonate bio-ceramic, which induces osteogenesis in bone marrow mesenchymal stem cells (MSCs), the cells responsible for maintaining bone homeostasis and orchestrating fracture repair. By 3D printing MSCs in coral-laden bioinks we utilise high throughput (HT) fabrication and evaluation of osteogenesis, overcoming the limitations of traditional screening methods.

MSC and coral-laden GelXA (CELLINK) bioinks were 3D printed in square bottom 96 well plates using a CELLINK BIO X printer with pneumatic adapter Samples were non-destructively monitored during the culture period, evaluating both the sample and the culture media for metabolism (PrestoBlue), cytotoxicity (lactose dehydrogenase (LDH)) and osteogenic differentiation (alkaline phosphatase (ALP)). Endpoint, destructive assays used included qRT-PCR and SEM imaging.

The inclusion of coral in the printed bioink was biocompatable with the MSCs, as reflected by maintained metabolism and low LDH release. The inclusion of coral induced osteogenic differentiation in the MSCs as seen by ALP secretion and increased RUNX2, collagen I and osteocalcin transcription.

Sustainably grown coral was successfully incorporated into bioinks, reproducibly 3D printed, non-destructively monitored throughout culture and induced osteogenic differentiation in MSCs. This HT fabrication and monitoring workflow offers a faster, less labour-intensive system for the translation of bone substitute materials to clinic.

Acknowledgements: This work was co-funded by Enterprise Ireland and Zoan Biomed through Innovation Partnership IP20221024.

With the success of the medial parapatellar approach (MPA) to total knee arthroplasty (TKA), current research is aimed at reducing iatrogenic microneurovascular and soft tissues damage to the knee. In an effort to avoid disruption to the medial structures of the knee, we propose a novel quadriceps-sparing, subvastus lateralis approach (SLA) to TKA. The aim of the present study is to compare if a SLA can provide adequate exposure of the internal compartment of the knee while reducing soft tissue damage, compared to the MPA. Less disruption of these tissues could translate to better patient outcomes, such as reduced post-operative pain, increased range of motion, reduced instances of patellar maltracking or necrosis, and a shorter recovery time.

To determine if adequate exposure could be achieved, the length of the skin incision and perimeter of surgical exposure was compared amongst 22 paired fresh-frozen cadaveric lower limbs (five females/six males) which underwent TKA using the SLA or MPA approach. Additionally, subjective observations which included the percent of visibility of the femoral condyles and tibial plateau, as well as the patellar tracking, were noted in order to qualify adequate exposure. All procedures were conducted by the same surgeon. Subsequently, to determine the extent of soft tissue damage associated with the approaches, an observational assessment of the dynamic and static structures of the knee was performed, in addition to an examination of the microneurovascular structures involved. Dynamic and static structures were assessed by measuring the extent of muscular and ligamentus damage during gross dissection of the internal compartment of the knee. Microneurovascular involvement was evaluated through a microscopic histological examination of the tissue harvested adjacent to the capsular incision.

Comparison of the mean exposure perimeter and length of incision was not significantly different between the SLA and the MPA (p>0.05). In fact, on average, the SLA facilitated a 5 mm larger exposure perimeter to the internal compartment, with an 8 mm smaller incision, compared to the MPA, additional investigation is required to assert the clinical implications of these findings. Preliminary analysis of the total visibility of the femoral condyles were comparable between the SLA and MPA, though the tibial plateau visibility appears slightly reduced in the SLA. Analyses of differences in soft tissue damage are in progress.

Adequate exposure to the internal compartment of the knee can be achieved using an incision of similar length when the SLA to TKA is performed, compared to the standard MPA. Future studies should evaluate the versatility of the SLA through an examination of specimens with a known degree of knee deformity (valgus or varus).

Purpose

Current coronoid fracture classification systems are based on fragment size and configuration using plain radiographs and/or CT. During surgery, coronoid fracture fragments appear much larger than anticipated because cartilage is radiolucent and therefore not taken into account with preoperative imaging. The purpose of this study was to quantify the articular cartilage thickness of the coronoid process, with reference to coronoid fracture classifications.

Posterior segmental fixation of the cervical spine facilitates fixation in sub-optimal bone, abnormal anatomy, and complex deformity. Compared to lateral mass plates a screw rod construct provides a stable construct in osteoporotic bone or in cases where the lateral masses are fractured or missing.

To investigate whether a posterior cervical screw- rod construct is an effective, stable and safe means of posterior cervical fixation.

Retrospective evaluation of consecutive patients undergoing a posterior cervical stabilization with a screw- rod construct with clinical and radiographic evaluation.

Clinical variables included age, gender, neurologic status, surgical indication, number of levels stabilized, and number of screws. Note was made as to whether a laminectomy was performed and concomitant anterior surgery. Clinical and radiographic assessments were carried out immediately after surgery and at six weeks, three, six, twelve months and annually after surgery.

Eighty-three patients had five hundred and seventy-three screws placed from October 1998 to December 2003. Mean patient age was fifty-seven. Mean follow-up was twenty-three months, (one to sixty months). The underlying diagnoses were inflammatory arthritis thirty-three, spondylotic myelopathy twenty-nine and trauma in twenty-one patients. Forty-four patients (53% had motor deficit, forty-seven patients (57%) had sensory deficit. Fixation was carried out over an average of five levels (range – two to eight). Mean number of screws per construct was seven (range – four to fourteen). The instrumentation was successfully implanted in all despite lateral mass deficiencies (fracture, poor bone) and coronal and sagittal plane deformities. Late occipital fixation failure was encountered in one patient. There was no loss of alignment or surgical correction on follow-up radiographs.

A posterior screw-rod system allows for treatment of traumatic and degenerative and inflammatory conditions. Crossing the occipitocervical or cervicothoracic junctions is easily afforded. We have had excellent success without complications from screw placement or pseudoarthrosis.

Introduction Spinal cord monitoring in posterior scoliosis surgery has become a standard of care. It has been our practice since 1999, to monitor the somato-sensory potential (SEP) and motor evoked potential (MEP) in all posterior cases. We report on and discuss the meaning of alteration in the spinal cord monitor signal that occurred in 15 cases from a total of 165 procedures.

Methods This is a retrospective review of patients from a hospital database. Over a six year period, 167 posterior scoliosis instrumented fusion procedures were performed by paired combinations of the four authors. In 13 cases we have been alerted to a change in one or both signals during the procedure. Associated with these, were two cases of intra-operative cardiac arrest, and six cases of post-operative neurological deficit. All patients remain under continued regular review.

Results In the two cases of intra-operative cardiac arrest, the SEP and MEP signals were lost approximately three minutes prior to the arrest. Both patients had neurological deficits post-operatively, one has totally recovered, and one has a residual complex regional pain syndrome of the right leg. This last patient is the only one of six who has not had complete resolution of the post-operative neurological deficit. In five of the six cases who sustained post-operative neurological deficits, the SEP and usually the MEP was lost and did not return. In the sixth case, the SEP did return. In the remaining seven cases, there were changes of decreased amplitude or increased latency in the SEP or MEP that did not appear to result in a postoperative clinical consequence, however; in two patients, signal changes were directly related to changes in blood pressure, and in two other patients, signal changes were directly related to concave hook placement.

Discussion On review of the management and outcome of these cases, we conclude that profound hypotension will alter the SEP and may herald a catastrophic cardiovascular or neurological event. Furthermore, the modality of continuous spinal cord monitoring can provide specificity in the diagnosis of an actual or impending neurological insult and allow for appropriate and timely intervention. We believe spinal cord monitoring in the posterior approach for spinal deformity is an invaluable tool, and is in fact, mandatory for all idiopathic and ambulant non-idiopathic spinal deformities.

Introduction: This study is a retrospective review of patients who underwent corticosteroid spinal injections and/or surgery for lumbar juxtafacet cysts to determine the effectiveness of corticosteroid injection and/or surgery for the treatment of lumbar juxtafacet cysts.

Methods: The charts of 40 patients who underwent corticosteroid injection and/or surgery for the treatment of symptomatic juxtafacet cysts were reviewed and an outcome questionnaire was sent to each patient. All patients responded to the questionnaire (100%).

Results: Forty-four juxtafacet cysts were treated in 40 patients. 28 cysts were initially treated with corticosteroid injection. 18 facet joints adjacent to the cysts were injected (4 were injected on two or more occasions), 13 underwent epidural injection and 5 underwent nerve sheath exit foraminal blocks. 18 obtained no Benefit from the use of corticosteroid injections and proceeded to surgical treatment. Of the 10 patients that did not undergo surgery, at follow-up 2 reported no clinical change and were considering surgical treatment. This represents a 71% failure rate for non-operative treatment with corticosteroid injections.

34 cysts were resected from 31 patients. Two (6%) were ligamental and 32 were facetal. 31 cysts were resected by laminectomy alone and 3 patients underwent laminectomy and bone only fusion. One cyst (3%) recurred and was managed by repeat laminectomy. One patient required instrumented lumbosacral fusion for increasing anterolisthesis. Incidental dural tear was the most common surgical complication occurring in two cases (6%). One patient demonstrated significant weakness of ankle and foot dorsiflexion which recovered incompletely. Average follow-up for the surgical group was 18 months (5–72 months). 27 scored an excellent or good outcome (79%), 3 scored a fair outcome, 3 were considered poor and one patient was worse. 30 (88%) patients were satisfied having complete improvement or improved with residual back or leg symptoms. Three responded as no change and one was worse.

Discussion: Juxtafacet cysts are an uncommon cause of radiculopathy. Corticosteroid injection into the adjacent facet joints, epidural space or exit foraminae of the spine produces disappointing results. Surgical resection is the treatment of choice with low rates of complications, recurrences and residual complaints.