Role of intraoperative Iso-C based navigation in challenging spine trauma

Background:

Pedicle screw fixation is the most preferred method of stabilizing unstable spinal fractures. Pedicle screw placement may be difficult in presence of fractured posterior elements, deformed spine, gross instability and spinal pathology. Challenging spine-fracture fixation is defined as the presence of one or more of the following: 1) obscured topographical landmarks as in ankylosing spondylitis, 2) fractures in occipitocervical or cervicothoracic regions and 3) preexisting altered spinal alignment. We report a series of pedicle screw insertion with guidance of navigation in difficult fixation problems..

Materials and Methods:

Fourteen patients [hangman''s fracture (n=3), odontoid fracture (n=4), C1C2 fracture (n=1) and spinal fracture with coexistent ankylosing spondylitis (n=6)] underwent posterior stabilization. Intraoperatively after surgical exposure, images were acquired by Iso-C 3D C-arm and transferred to navigation system. Instrumentation was performed with navigational assistance. Postoperatively, placements of pedicle screws were evaluated with radiographs and CT scan.

Results:

Sixty-seven pedicle screws (cervical, n=33; thoracic, n=6; lumbar, n=26; sacral n=2) and 15 lateral mass screws were inserted with navigation guidance. The average time of image data acquisition by Iso-C 3D C-arm and its transfer to workstation was 4 minutes (range, 2-6 minutes). Postoperative CT scan revealed ideal placement of screws in 63 pedicles (94%), grade 1 cortical breaches (<2 mm) in 3 pedicles (4.5%) and grade 2 cortical breach (2-4 mm) in one pedicle (1.5%). There were no neurovascular complications. Deep infection was encountered in one case, which settled with debridement.

Conclusions:

Intraoperative Iso-C 3D C-arm based navigation is a useful adjunct while stabilizing challenging spinal trauma, rendering feasibility, accuracy and safety of pedicle screw placement even in difficult situations.     

Restoration of compressive loading properties of lumbar discs with a nucleus implant—a finite element analysis study

Background ContextDiscectomy is a common procedure for treating sciatica. However, both the operation and preceding herniated disc alter the biomechanical properties of the spinal segment. The disc mechanics are also altered in patients with chronic contained herniation. The biomechanical properties of the disc can potentially be restored with an elastomeric nucleus replacement implanted via minimally invasive surgery.PurposeThe purpose of this study was to determine whether the compressive characteristics of the intervertebral disc after a nucleotomy can be restored with an elastomeric nucleus replacement.Study DesignA finite element model of the L4–L5 intervertebral disc was created to investigate the effect of the implantation of an elastomeric nucleus replacement on the biomechanical properties of the disc under axial loading.MethodA L4–L5 physiologic intervertebral disc model was constructed and then modified to contain a range by volume of nucleotomies and nucleus replacements. The material properties of the nucleus replacement were based on experimental data for an elastomeric implant. The compressive stiffness, radial annular bulge, and stress distribution of the nucleotomy and nucleus replacement models were investigated under displacement-controlled loading.ResultsRemoval of nucleus pulposus from the physiologic disc reduced the force necessary to compress the disc 2 mm by 50%, altered the von Mises stress distribution, and reduced the outward radial annular bulge. Replacing the natural nucleus pulposus of the physiologic disc with an artificial nucleus reduced the force required to compress the disc 2 mm by 10%, indicating a restoration of disc compressive stiffness. The von Mises stress distribution and annular bulge observed in the disc with an artificial nucleus were similar to that observed in the physiologic disc.ConclusionThis study demonstrates that despite having different material properties, a nucleus replacement implant can restore the axial compressive mechanical properties of a disc after a discectomy. The implant carries compressive load and transfers the load into annular hoop stress.     

Management of urethral recurrence after orthotopic urinary diversion

Study Type – Therapy (case series)
Level of Evidence 4

OBJECTIVE

To evaluate our experience with urethral recurrences in patients treated by radical cystectomy(RC) and orthotopic neobladder urinary diversion for carcinoma of the bladder.

PATIENTS AND METHODS

We retrospectively reviewed the records of patients treated with RC and orthotopic urinary diversion between January 1980 and July 2004.

RESULTS

In all, 260 patients underwent RC with a Studer or Hautmann orthotopic urinary diversion; the median (range) follow‐up was 5.1 (0–15.6) years. Six patients (2.3%) developed local recurrence of urothelial cancer (UC) within the urethra after this treatment. The median (range) time to presentation with recurrence after RC was 2.4 (0.7–3.6) years for pT1‐4 UC. Recurrences were treated with various methods, including transurethral resection, urethrectomy with conversion of neobladder to continent catheterizable diversion, and chemotherapy. At the last follow‐up, four of these six patients were alive without disease, one was alive with disease, and one had died from disease.

CONCLUSIONS

In our experience, local recurrences involving the urethra are infrequent. Complete surgical excision can provide a good outcome. Neoadjuvant chemotherapy should be considered for recurrences with adverse clinicopathological features.     

International validation of the prognostic value of lymphovascular invasion in patients treated with radical cystectomy

Study Type – Prognosis (retrospective cohort)
Level of Evidence 2b

OBJECTIVE

To externally validate the prognostic value of lymphovascular invasion (LVI) in a large international cohort of patients treated with radical cystectomy (RC) for urothelial carcinoma of the bladder (UCB).

PATIENTS AND METHODS

We collected data from 4257 patients treated with RC and pelvic lymphadenectomy for UCB, without neoadjuvant chemotherapy, at 12 centres. LVI was defined as presence of nests of tumour cells within an endothelium‐lined space.

RESULTS

LVI was detected in 1407 patients (33.1%); the proportion of LVI increased with advancing stage, higher grade, soft‐tissue surgical margin involvement, and lymph node metastasis (P < 0.001 for all). In standard multivariate models, LVI was associated with both disease recurrence (hazard ratio 1.43, P < 0.001) and cancer‐specific mortality (1.45, P < 0.001). In the entire cohort, adding LVI to a base model that included standard features improved only minimally its predictive accuracy for both recurrence and cancer‐specific mortality (by 1.1% and 1.2%, respectively). In 3122 patients with negative lymph nodes, LVI remained independently associated with and improved the predictive accuracy of the standard predictors for recurrence (hazard ratio 1.68, P < 0.001; +2.3%) and cancer‐specific mortality (1.70, P < 0.001; +2.4%). By contrast, in 1071 node‐positive patients, LVI only marginally improved the prediction of cancer‐specific recurrence (hazard ratio 1.20, P < 0.001; +0.2%) and survival (1.23, P < 0.001; +0.5%).

CONCLUSIONS

LVI is strongly associated with clinical outcome in node‐negative patients treated with RC. The assessment of LVI might help to identify patients who could benefit from adjuvant therapy after RC. After confirmation in different populations, LVI should be included in the staging of UCB.     

Closed Transverse Pinning for Reduction and Fixation of Metatarsal Neck Fractures: Surgical Technique

Most metatarsal neck fractures can be successfully treated non-operatively in a cast boot. Displaced metatarsal neck fractures tend to be less stable and have a propensity for the distal fragment to angulate, secondary to the strong flexor tendons, which often forces the distal fracture fragment in a plantar direction and leads to relative metatarsal shortening. Most literature is focussed on antegrade fixation of metatarsal neck fractures using pre-bent K wires or thin elastic nails. Apart from the technical challenges, this technique is limited when bones are osteoporotic as the pre-bent distal end of the K-wire may penetrate the plantar cortex of the proximal metatarsal and prevent the wire from entering the medullary canal of the metatarsal and advancing to the fracture site. Furthermore, when the medullary canal is narrow especially in Asian patients, it may be difficult to pass a bent K-wire through the isthmus of the metatarsal shaft. We describe an innovative technique of closed transverse wiring of the metatarsal head necks that has a distinct advantage in Asian population with osteoporotic bones. With percutaneous manipulation using digital pressure, closed reduction of fracture fragments of the most displaced fracture is done under fluoroscopic guidance to achieve a satisfactory alignment followed by closed transverse wiring of the metatarsal heads. With this procedure, adjacent fractures remain stable within an acceptable range because of intermetatarsal ligaments connected to the adjacent intact head. Our technique has a relatively short operating time and allows for early motion of the metatarso-phalangeal joint. This is especially useful for those with osteoporosis, narrow canal, soft tissue compromise, intra-operative failure of ante-grade pinning and in scenarios of limited surgical equipment/expertise.     

Coronary endarterectomy on beating heart: Our experience

Introduction Coronary artery bypass grafting (CABG) associated with Endarterectomy is a high risk procedure. After the first report of coronary endarterectomy by Bailey et al in 1951, the preference for this surgical procedure was decreased due to increased morbidity and mortality In patients with total or subtotal large coronary artery obstructions in which there is no possibility to receive a conduit as graft for myocardial revascularisation, endarterectomy remains the procedure of choice. This study was designed to study early and midterm results of off pump coronary artery endarterectomy. Methods Of 172 Consecutive Off Pump CABG done at our institution from Jan 2003 to July 2005, 22 patients underwent supplementary coronary endarterectomy. 16 patients had chronic stable angina 4 had unstable angina two required emergency CABG with endarterectomy following perioperative infarction. The mean ejection fraction was 29.2±4.3 and all of the patients were in New York Heart Association (NYHA) III or IV. All patients were planned for complete total arterial revascularisation using Left Internal Mammary Artery (LIMA). Right Internal Mammary Artery (RIMA), Radial composite “Y” graft, Two patients operated for periop infarct received vein graft. In 16 patients closed endarterectomy was done in five patients double endarterectomy in single vessel was done to chase the plaque distally, in one patient open left anterior descending (LAD) endarterectomy with vein patch reconstruction was performed. Results There were no deaths. None of the procedures were converted to on pump operation. All endarterectomies and bypasses were performed on Beating Heart, all patients were completely revascularised. Peri operative cardiac enzymes studied showed no significant rise in the Creatinine Phoshpokinase (CPK)-Creatinine Phosphokinase myocardial Band (CPK-MB). The mean postoperative Ejection Fraction (EF) was 36.7%±7.2% which was significantly higher than the Preoperative one (p<.05). At the end of four months to one and half year 22 patients were in NYHA class I to II and all were angina free in canadian cardiovascular society class.f Conclusions Coronary End Arterectomy without cardiopulmonary bypass can be performed in patients who are expected to benefit from complete revascularisation. It can be performed with closed as well as open method. However to achieve complete endarterectomy by closed technique in some patients it is essential to chase the plaque. Early and mid term results are encouraging.     

Covalent linking of proteins and cytokines to suture: enhancing the immune response of head and neck cancer patients

BACKGROUND: The immune system of advanced stage head and neck cancer patients is frequently suppressed. Poor immune function has been correlated with poor clinical outcome. Immunotherapeutic strategies have been previously attempted in an effort to enhance immune function and improve survival. Previous studies have shown surgical suture can be transformed into an immune stimulant capable of activating the T lymphocytes of cancer patients. The development of a process for covalently linking proteins and cytokines to suture could have enormous potential for the in vivo manipulation of the immune system. HYPOTHESIS: We hypothesize proteins and cytokines can be covalently linked to surgical suture while preserving their functional properties. STUDY DESIGN: Prospective study testing normal donor and head and neck squamous cell carcinoma (HNSCC) patient lymphocytes. METHOD: Polyester suture was acid hydrolyzed followed by reacting with 1-ethyl-3(-3-dimethylamino propyl carbodiimide) (EDAC) to create a suture-EDAC intermediate. Next, selected proteins (horseradish peroxidase [HRP] or bovine serum albumin [BSA]) or cytokines (interleukin [IL]-2 or interferon [IFN]-gamma) were reacted with the suture-EDAC intermediate to test the covalent linkage of the selected protein or cytokine to suture. Functional activity of the linked proteins was measured spectrophotometrically. The linking of cytokines to suture was tested by stimulating normal donor peripheral blood lymphocytes (PBL) or HNSCC patients' lymphocytes. The functional activity was confirmed by proliferation, enzyme linked immunoadsorbent assay (ELISA), and phenotype expression of T cells.RESULTS The conditions for optimally linking a protein to polyester suture were defined using HRP as a model protein. HRP retained its enzymatic activity. The optimal conditions for linking IL-2 or IFN-gamma were defined. The covalently linked cytokines retained their immune enhancing properties for stimulating PBL and lymph node lymphocytes (LNL) from HNSCC patients to proliferate, generate a TH1 immunologic profile of cytokines (IL-2, IL-12, IFN-gamma), and stimulate T lymphocytes. CONCLUSION: This is the first report to demonstrate that cytokines can be covalently linked to surgical sutures and retain their immune-stimulating properties. Proteins linked to suture also retained their enzymatic activity. The clinical implications of functionally active cytokines or proteins linked to surgical suture may be very significant in the future for manipulating the immune system in vivo or enhancing wound healing.