Rahul Vaidya

Complications in the Use of rhBMP-2 in PEEK Cages for Interbody Spinal Fusions

Study Design All patients of spinal interbody fusion using polyetheretherketone (PEEK) cages and recombinant human bone morphogenetic protein (rhBMP)-2 performed over a 16-month period were reviewed. Objective To determine the suitability of PEEK cages when used in conjunction with rhBMP-2 in interbody spinal fusion. Summary of Background Data Bone morphogenetic proteins are increasingly being used in spinal fusion to promote osteogenesis. PEEK is a semicrystalline aromatic polymer that is used as a structural spacer to maintain the disc and foraminal height. Their use has led to increased and predictable rates of fusion. However, not many reports of the adverse effects of their use are available. Methods Fifty-nine consecutive patients of interbody spinal fusion in the cervical or lumbar spine using a PEEK cage and rhBMP-2 were followed for an average of 26 months after surgery. A clinical examination and a record of Oswestry Disability Index, Visual Analog Scale for pain, and a pain diagram were performed preoperatively and at every follow-up visit. All patients had plain radiographs carried out to assess fusion. Ten patients of lumbar spine fusion were additionally evaluated with a computed tomography scan. Results All cases demonstrated an appreciable amount of new bone formation by 6 to 9 months in the cervical spine and by 9 to 12 months in the lumbar spine. End plate resorption was visible radiologically in all cervical spine fusions and majority of lumbar fusions. Cage migration was observed to occur maximally in patients with transforaminal lumbar interbody fusion and posterior lumbar interbody fusion. Disc space subsidence was seen in both cervical and lumbar arthrodesis with the latter showing a lesser incidence, but with a greater degree of collapse. Conclusions PEEK cages and rhBMP-2 when used in spinal fusion give consistently good fusion rates. However, the early role of BMP in the resorptive phase may cause loosening, cage migration, and subsidence.

Lumbar Spine Fusion in Obese and Morbidly Obese Patients

Study Design. Single-center retrospective study. Objective. The aim of the study was to compare the surgical experience, clinical outcomes, and effect on body weight between obese and morbidly obese patients undergoing lumbar spine fusion surgery. Summary of Background Data. Obese and morbidly obese patients undergoing spinal fusion surgery are a challenge to the operating surgeon. Only few reports are available on the perioperative data in this group of patients. Further, it is unknown if the degree of obesity has an effect on the surgical experience and clinical outcomes including body weight. Methods. A retrospective study of 63 patients undergoing lumbar spinal fusion was carried out. The main inclusion criteria were a body mass index (BMI) equal to or greater than 30. Information recorded included surgical set-up time, surgical time, blood loss, American Association of Anesthesiologists score, and surgical complications. At follow-up, the Oswestry Disability Index and visual analog scale for back and leg pain were recorded along with a pain diagram and radiographic evaluation. Results. The obese group had lower American Association of Anesthesiologists scores. The surgical time was dependent on the number of levels fused and was independent of the BMI. Blood loss during surgery was marginally greater in the obese patients. Neither group showed significant change in weight and BMI. Clinical outcomes showed improvement in visual analog scale for back and leg pain with some improvement in Oswestry scores and were independent of the BMI of the patient. The incidence of postoperative complications was significant in 45% of morbidly obese and 44% of obese patients. Conclusion. Obese and morbidly obese patients have multiple comorbidities, and the spinal surgeon should be prepared to encounter perioperative complexities. Operative times are longer in comparison with normal weight patients with a higher incidence of postoperative complications. No weight loss occurs after spinal surgery.

Treatment of unstable pelvic ring injuries with an internal anterior fixator and posterior fixation: initial clinical series.

Objectives: To present a novel internal fixation device for stabilizing unstable pelvic fractures using supra-acetabular spinal pedicle screws and a subcutaneous connecting rod (INFIX). Setting: Level I trauma center. Design: Case series. Patients: Twenty-four patients with rotational or vertically unstable pelvic fractures that reported to a level I trauma center. Methods/intervention: Surgical treatment of unstable pelvic fractures included reduction, appropriate posterior fixation where indicated, and an anterior subcutaneous internal fixator. Main Outcome Measurement: Healing time, quality and loss of reduction, ease of nursing, incidence of complications, including nonunion, infection, and patient mobility and comfort. Results: In the present clinical series, all fractures healed without significant loss of reduction. There were no infections, delayed unions or nonunions. Nursing care was observed to be easier especially in the intensive care unit setting. Complications included unilateral anterior thigh paresthesias in 2 patients, and 1 patient each required repositioning of the pedicle screw and readjustment of screw rod junction. Patients tolerated the procedure well and were fairly mobile after the procedure. Conclusions: The reported technique allows for a definitive and stable anterior fixation of vertically and rotationally unstable pelvic fractures when combined with the appropriate posterior fixation if indicated. The potential complications are acceptable with this technique and good outcomes were achieved. A second operative procedure is required for removal of the device. It is our view that its best indication is in obese individuals, in whom other options have shortcomings.

Unusual spinal manifestation in secondary hyperparathyroidism: a case report.

Study Design. Case report. Objectives. To describe an unusual spinal manifestation of secondary hyperparathyroidism in a 29-year-old woman and discuss the pathologic basis of the disease and evaluate the response to treatment. Summary of Background Data. Extraskeletal tumoral calcification (i.e., tumoral calcinosis, tumoral calcinosis-like lesion, calcifying pseudoneoplasms) is an uncommon entity associated with secondary hyperparathyroidism. Involvement of the cervical spine with this tumor causing neural compression is extremely rare. Only a few cases have been reported in literature and none with a concomitant presence of brown tumors. Methods. A 29-year-old woman presented with upper back pain with tingling and weakness in the left hand. She had been on dialysis for 5 years following renal failure. She had a partial parathyroidectomy for hyperparathyroidism a year ago. Para vertebral calcification eroding the posterior elements of C6–T2 and abutting the dura and neural foramens was seen on a CT scan. There were numerous lytic defects of the thoracic and lumbar vertebral bodies, most notable at L4, suggesting focal brown tumors. An MRI scan of the spine demonstrated a large heterogeneously hypointense lesion of the cervicothoracic spine, which remained hypointense on T2 images. A cervicothoracic decompression and spinal stabilization from the front and back was performed. A pathologic diagnosis of tumoral calcinosis-like lesion was confirmed. Result. Following surgery, the patient recovered neurologically and subsequently underwent total parathyroidectomy. Presently, her bone lesions have healed. Conclusion. Hyperparathyroidism may cause tumoral calcinosis-like lesions in the spine. An early spinal decompression followed with parathyroidectomy leads to remission of symptoms.

The bikini area and bikini line as a location for anterior subcutaneous pelvic fixation: An anatomic and clinical investigation.

Anterior external fixation for pelvic fractures has been the standard for acute stabilization but definitive treatment often leads to pin tract infection, is uncomfortable, and limits patient mobility. We recently developed a subcutaneous anterior pelvic fixator which addresses these issues (INFIX). The objective of this study is to introduce the Bikini Area and Bikini Line as the subcutaneous anatomical location where this apparatus is placed. A study was preformed on eight cadaveric specimens to define the location of the subcutaneous device with respect to anatomic structures. We examined 23 people of various body mass indexes to examine the anterior pelvic anatomy. This was followed by implantation on 42 individuals in whom we reviewed CT scans to assess the location of the implant. We asked these same 42 individuals whether they could sit, stand, and lie on their sides and if they had any discomfort. We measured the dimensions of 26 retrieved rods to approximate the curve of the Bikini Line. Finally in 14 individuals we performed vascular ultrasound to assess the flow in the iliac and femoral vessels with the implant in place in the sitting and standing position. Neurovascular structures are not affected by placing the INFIX device at the Bikini Line, patients are comfortable, mobile and complications are minimized by this procedure. A rod placed on the Bikini Line which connects screws inserted into the anterior inferior iliac spine on each side does not interfere with sitting, standing, or the neurovascular structures. Clin. Anat., 2013.

SEPTIC ARTHRITIS IN INTRAVENOUS DRUG ABUSERS: A HISTORICAL COMPARISON OF HABITS AND PATHOGENS

BACKGROUND Intravenous drug abuse (IVDA) is a common problem; there were more than 16 million users worldwide in 2008. Numerous reports highlight the infectious skeletal complication associated with IVDA. OBJECTIVE To determine septic arthritis pathogens in IVDA in a U.S. hospital and compare the current causative organisms to a cohort from the 1980s at the same institution. METHODS An institutional review board-approved retrospective cohort study compared a consecutive series of IVDA septic arthritis patients over a 10-year period, 1999-2008 (Group B), with an IVDA septic arthritis database that was collected in the 1980s (Group A). Endpoints were: bacterial species and staph species antibiotic susceptibility. RESULTS Group B included 58 patients (35 men, 23 women) with a median age of 46.5 years. Group A included 38 patients (30 men, 8 women), with a median age of 32.5 years. The sets were significantly different in pathogens (p = 0.0443). The most common organisms were Staphylococcus (staph) species (B 74.51%, A 52.63%), followed by Streptococcus (strep) species (B 7.84%, A 31.58%), Pseudomonas (B 13.73%, A 13.16%), and Serratia (B 3.92%, A 2.63%). Of the total number of septic joints, methicillin-resistant Staphylococcus aureus (MRSA) made up 39% of Group B and 34% of Group A. However, within the staph species, MRSA made up 53% of Group B and 65% of Group A. Strep species made up 7.84% (Group B) vs. 31.58% (Group A), and Pseudomonas (13%) and Serratia (3-4%) were similar. In the Group B cohort, methicillin-susceptible Staphylococcus aureus (MSSA) had a predilection to infect the knee (94.4%), whereas MRSA was found more often in the hip (57.1%). CONCLUSIONS In IVDAs, MRSA is the most common pathogen causing septic arthritis. The ratio of staph species in septic joints is increasing, and the ratio of MRSA to MSSA remains high (>50%). Strep species are much less common.

Monoaxial Pedicle Screws Are Superior to Polyaxial Pedicle Screws and the Two Pin External Fixator for Subcutaneous Anterior Pelvic Fixation in a Biomechanical Analysis

Purpose. Comparison of monoaxial and polyaxial screws with the use of subcutaneous anterior pelvic fixation. Methods. Four different groups each having 5 constructs were tested in distraction within the elastic range. Once that was completed, 3 components were tested in torsion within the elastic range, 2 to torsional failure and 3 in distraction until failure. Results. The pedicle screw systems showed higher stiffness (4.008 ± 0.113 Nmm monoaxial, 3.638 ± 0.108 Nmm Click-x; 3.634 ± 0.147 Nmm Pangea) than the exfix system (2.882 ± 0.054 Nmm) in distraction. In failure testing, monoaxial pedicle screw system was stronger (360 N) than exfixes (160 N) and polyaxial devices which failed if distracted greater than 4 cm (157 N Click-x or 138 N Pangea). The exfix had higher peak torque and torsional stiffness than all pedicle systems. In torsion, the yield strengths were the same for all constructs. Conclusion. The infix device constructed with polyaxial or monoaxial pedicle screws is stiffer than the 2 pin external fixator in distraction testing. In extreme cases, the use of reinforcement or monoaxial systems which do not fail even at 360 N is a better option. In torsional testing, the 2 pin external fixator is stiffer than the pedicle screw systems.

Esophageal perforation following cervical spine surgery: A review with considerations in airway management

Anterior cervical discectomy and fusion (ACDF) is a commonly performed surgery for the treatment of spondylosis, radiculopathy, myelopathy, and trauma to the cervical spine. Esophageal perforation is a rare yet serious complication following ACDF with an incidence of 0.02 to 1.52%. We describe a case of a 24-year-old man who underwent ACDF and corpectomy following a motor vehicle accident who subsequently developed delayed onset esophageal perforation requiring surgical intervention. We believe that the detailed review of the surgical management of esophageal perforation following cervical spine surgery will provide a deeper understanding for the Intensivist in regards to postoperative airway management in these types of patients. Careful extubation over a soft flexible exchange catheter should take place to help reduce the risk of perforation in the event reintubation is required.

INFIX versus plating for pelvic fractures with disruption of the symphysis pubis

PurposeThe purpose of this study is to compare INFIX to plating in the treatment of unstable pelvic ring injuries with disruption of the symphysis.MethodsTwenty-four patients treated with INFIX were compared to 28 patients fixed by plating. All patients had anterior and posterior fixation. Injuries were classified using the Young and Burgess and AO/OTA classification systems. Reductions of the pelvic ring were assessed using the pelvic deformity index (PDI) and symphyseal widening. Patients were contacted to get functional outcomes using the Majeed scoring system and complications were tabulated .ResultsINFIX was inferior to plating at reducing symphyseal widening (INFIX 10.72± 5.0 Plates 6.97 ± 3.39 P = 0.012) but similar in reducing the pelvic deformity index. (INFIX 0.0221± .015 Plates 0.0190 ± .0105 P = 0 .38). Majeed scores were similar 83.95 ± 15.2 (median 89, range 51-100) for INFIX and 77.67± 16.7 (median 79, range 54-100) for plating. Complications included infection (1 (4%) INFIX , 4 (14%) plates), improper hardware placement or failure (2 (8%) INFIX, 3 (11%) plates), and heterotopic ossification (11 (46%) INFIX, 16 (57.1%) plates). Infection in the plated patients was related to urological injury in 3/4 cases.ConclusionsPlating provides better reduction of the pubic symphysis and requires only one surgery. Outcomes scores were similar. INFIX may be preferable in obese patients, young women of childbearing age or those with urological injury.

The Anterior Subcutaneous Pelvic Fixator (INFIX) in an Anterior Posterior Compression Type 3 Pelvic Fracture.

Objectives: The purpose of this video is to describe the equipment, anatomy, and surgical technique of anterior subcutaneous pelvic fixation (INFIX) using pedicle screws and a rod in an Anterior Posterior Compression 3 pelvic fracture, as well as how to distract in lateral compression fractures. Methods: The equipment required includes standard spine pedicle screw sets with long screws, 70–110 mm in length, and 7 or 8 mm in diameter. The approach is a mini open and one needs to be familiar with the iliac oblique, obturator outlet, and obturator inlet views. The length of the screw is measured from the sciatic notch to the skin, and they are placed so that the head sits just below the skin. The rod is passed just under the skin along the bikini line and the construct compressed or distracted against a c-clamp while monitored with fluoroscopy. In Orthopaedic Trauma Association C type injuries, we leave c-clamps on the outside the screws to reinforce them or use monoaxial screws. The implants are removed at 3–6 months postop. Results: The patients tolerate the implants and are able to sit and stand with out difficulty. Complications include lateral femoral cutaneous nerve irritation, heterotopic bone, loss of fixation if the implants are applied incorrectly. Conclusions: The INFIX procedure for anterior pelvic fixation is based on standard techniques that are familiar to the Orthopaedic Pelvic Surgeon including supraacetabular screws. Rod bending, rod passing, determining the ideal height of the screws, and distraction/compression maneuvers are demonstrated in this video.