Bidre Upendra

Outcome-based Classification for Assessment of Thoracic Pedicular Screw Placement

Study Design. Prospective cohort study. Objective. We propose a simple outcome-based classification for assessment of pedicle screw positions based on postoperative computed tomography scan. This bridges the gap between high rates of pedicle screw misplacement and minimal complications reported. Summary of Background Data. The main deterrent for the use of thoracic pedicular screws is the feared neurovascular complications due to screw “misplacements.” The literature shows that only a small fraction of the misplaced screws actually causes any complication, and some misplacements can be acceptable both in terms of safety and their biomechanical strength. Methods. Sixty patients with various spinal disorders were included in the study. The mean age was 29.6 years (range, 12–72 years). The patients were divided into 2 groups for assessment of pedicle screw placements using postoperative computed tomography scans: scoliosis group with 24 patients and the nonscoliosis group with 34 patients. Placements of screws were assessed using the outcome-based classification and the Rongming Xu criteria of screw placement. Results. A total of 341 screws were assessed from 60 patients with various spinal disorders (scoliosis and nonscoliosis groups). Using the Rongming Xu criteria, the overall screw misplacement in scoliosis group was 50.72% (68 of 138) and that in nonscoliosis group was 45.45% (80 of 176 screws). Assessment of these screws using the outcome-based classification showed a high percentage of acceptable screw placements (type 1) − 89.85% (124 of 138 screws) in the scoliosis group and 86.93% (153 of 176 screws) in the nonscoliosis group. Conclusion. The literature shows consensus over high rates of pedicle screw misplacement, but low clinical complications, in the hands of the best of spine surgeons. The concept of acceptable screw placements and the outcome classification makes the pedicle screw assessment results correlate better with the clinical outcome.

Anterior versus posterior procedure for surgical treatment of thoracolumbar tuberculosis: A retrospective analysis.

Background: Approach for surgical treatment of thoracolumbar tuberculosis has been controversial. The aim of present study is to compare the clinical, radiological and functional outcome of anterior versus posterior debridement and spinal fixation for the surgical treatment of thoracic and thoracolumbar tuberculosis. Materials and Methods: 70 patients with spinal tuberculosis treated surgically between Jan 2001 and Dec 2006 were included in the study. Thirty four patients (group I) with mean age 34.9 years underwent anterior debridement, decompression and instrumentation by anterior transthoracic, transpleural and/or retroperitoneal diaphragm cutting approach. Thirty six patients (group II) with mean age of 33.6 years were operated by posterolateral (extracavitary) decompression and posterior instrumentation. Various parameters like blood loss, surgical time, levels of instrumentation, neurological recovery, and kyphosis improvement were compared. Fusion assessment was done as per Bridwell criteria. Functional outcome was assessed using Prolo scale. Mean followup was 26 months. Results: Mean surgical time in group I was 5 h 10 min versus 4 h 50 min in group II (P>0.05). Average blood loss in group I was 900 ml compared to 1100 ml in group II (P>0.05). In group I, the percentage immediate correction in kyphosis was 52.27% versus 72.80% in group II. Satisfactory bony fusion (grades I and II) was seen in 100% patients in group I versus 97.22% in group II. Three patients in group I needed prolonged immediate postoperative ICU support compared to one in group II. Injury to lung parenchyma was seen in one patient in group I while the anterior procedure had to be abandoned in one case due to pleural adhesions. Functional outcome (Prolo scale) in group II was good in 94.4% patients compared to 88.23% patients in group I. Conclusion: Though the anterior approach is an equally good method for debridement and stabilization, kyphus correction is better with posterior instrumentation and the posterior approach is associated with less morbidity and complications.

Video-assisted thoracoscopic anterior surgery for tuberculous spondylitis.

In the absence of major deformity, the major goal of surgery in tuberculous spondylitis is to achieve adequate cord decompression and débridement of diseased tissue. We asked whether video-assisted thoracoscopic surgery (VATS) could be undertaken in active tuberculosis of the spine with instrumentation and achieve good healing of the disease with fusion and with adequate decompression of the cord to achieve neural recovery. We retrospectively reviewed 23 patients (13 men and 10 women with an average age of 38.2 years) with single-level thoracic spinal tuberculosis (T4-T11) treated with VATS. Of the 23 patients, 18 had paraparesis/paraplegia. The procedures included: (1) débridement and drainage of prevertebral and paravertebral abscess (n = 4); (2) débridement, decompression, and reconstruction with rib graft (n = 8); (3) débridement, decompression, anterior vertical titanium mesh cage, and open posterior screw-rod fixation (n = 5); and (4) débridement, decompression, and anterior screw-rod fixation (n = 6). Twenty-two of 23 patients achieved fusion and there was no recurrence of the disease in any of the patients. No patient had neurological deterioration and 17 of the 18 neurologically compromised patients regained ambulatory power. Small scars (for surgical portals), early mobilization, and short hospital stays were the salient advantages.Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The medial cortical pedicle screw—a new technique for cervical pedicle screw placement with partial drilling of medial cortex

BACKGROUND CONTEXT Studies on cadavers have shown that the appropriate insertion of cervical pedicle screw (C3-C7) should be done from a more lateral point and at a steeper angle in the axial plane, than that described by Abumi et al., to decrease the chances of lateral perforation. PURPOSE We describe a new technique for cervical pedicle screw (CPS) placement (C3-C7) using high-speed pneumatic drill with partial drilling of medial cortex for decreasing the chances of lateral perforation. STUDY DESIGN Description of new surgical technique with retrospective data analysis. PATIENT SAMPLE Twenty-five patients undergoing cervical spine surgery with CPS instrumentation in the lower cervical spine (C3-C7) from April 2011 to October 2012 at our institute were included in the study. OUTCOME MEASURES All patients were evaluated with computed tomography scans postoperatively for the assessment of pedicle screw placement. Pedicle screw perforations were graded with the following criteria: Grade I perforations having ≤50% of the screw outside the pedicle and Grade II perforations having >50% of the screw outside the pedicle. Clinical complications directly related to CPS placement were also recorded. METHODS Twenty-five patients undergoing surgery with CPS instrumentation (C3-C7) at our institute between April 2011 and October 2012 were included in the study. Thirteen patients had cervical trauma, 10 had cervical spondylotic myelopathy, 1 had congenital cervico-dorsal scoliosis, and 1 was a patient with ankylosing spondylitis. Pedicle screw insertion was made according to the technique by Abumi et al., with the use of blunt pedicle probes in eight of these cases (Group I). In the other 17 cases (Group II), the pilot hole was made with the use of 2-mm diamond tipped burr, partially drilling the medial cortex and entering the vertebral body with the burr itself. RESULTS A total of 131 CPSs (C3-C7) were inserted in 25 patients. In Group I, 43 pedicle screws were placed and 88 screws were placed in Group II, with partial drilling of medial cortex. Lateral perforations: in Group-I, more of lateral perforations were observed with 18.6% Grade I and 9.3% Grade II lateral perforations. In Group II, the lateral perforations were lower with 7.95% Grade I and 1.1% of Grade II lateral perforations. I Group-I, medial perforations were lower with 11.62% Grade I and 2.3% Grade II perforations. In Group II, the Grade I and Grade II medial perforations were 30.7% and 4.5%, respectively. The lateral perforations were more at C3, C4 levels, and the medial perforation was maximum at C5 level. No clinical neurovascular complications, directly related to screw placements, were seen in either of the groups postoperatively. CONCLUSIONS With the use of the technique by Abumi et al., more than half of the cervical pedicle screw perforations described are lateral. Use of a blunt pedicle probe usually directs the surgeon toward the lateral cortex as the medial cortex is thicker and stronger. With the new medial cortical pedicle screw technique described, lateral perforations were low. However, surgeons attempting this technique should be aware of the increase in medial perforations experienced by the authors with the new technique. The study gives an additional option of technique to be considered by surgeons already using CPS placements in selected patients. Further evaluation for reproducibility of the medial cortical pedicle screw technique by other surgeons and testing of biomechanical strength of the screws is required.

Pedicle morphometry in patients with adolescent idiopathic scoliosis.

Background: The key to the safe and effective use of thoracic pedicle screws in the deformed spine is to thoroughly understand pedicle anatomy. There are a few studies related to pedicle anatomy in the Indian population and no pedicle morphometric studies in scoliosis patients. The present study aims to highlight the differential features of pedicle morphometry, including pedicle width, transverse pedicle angle and the depth to anterior cortex on the concave and convex side, in a group of Indian patients with adolescent idiopathic scoliosis and compare this to that of a western population. Materials and Methods: This is a prospective study of 24 patients with adolescent idiopathic scoliosis. The average age is 14.6 years (12.3-18.3 years) of which 14 were females and 10 were males. All the patients underwent CT scan using Siemens 4th generation scanner. The scans were analyzed by measuring the transverse pedicle width, transverse pedicle angle and the chord length; all the measurements being made both on the convex as well as the concave pedicle. Statistical analysis was performed with unpaired ‘t’ test. Results: A total of 1295 measurements were performed from 24 patients and an average of 215 pedicles were assessed for each set of the measurements made. The transverse pedicle width was consistently found to be smaller on concave side in comparison with the convex side at all levels except at T1. The transverse pedicle angle was greater on the concave side at all levels as compared to the convex side, though there was wide individual variation. The depth to anterior cortex was lesser on convex side in comparison to the concave side except at T1. Conclusions: The concave pedicle is much thinner and directed more medially than the convex side, especially at the apical region of the scoliotic curve. The pedicle anatomy in scoliosis patients shows very high individual variations and a careful study of pre-operative CT scans is essential for planning proper pedicle screw placement. Slightly longer screws can be accommodated on the concave side as compared to the convex side, though the difference in the chord length is not statistically significant at most levels.

Correlation of outcome measures with epidemiological factors in thoracolumbar spinal trauma

Background: The epidemiological data of a given population on spinal trauma in India is lacking. The present study was undertaken to evaluate the profile of patients with thoracolumbar fractures in a tertiary care hospital in an urban setup. Materials and Methods: Four hundred forty patients with thoracolumbar spinal injuries admitted from January 1990 to May 2000 to the All India Institute of Medical Sciences were included in the analysis. Both retrospective data retrieval and prospective data evaluation of patients were done from January 1998 to May 2000. Epidemiological factors like age, sex and type of injury, mode of transport, time of reporting and number of transfers before admission were recorded. Frankels grading was used to assess neurological status. Functional assessment of all patients was done using the FIM™ instrument (Functional Independence Measure). Average followup was 33 months (24-41 months). Results: Of the 440 patients, females comprised 17.95% (n=79), while 82.04% (n=361) were males. As many as 40.9% (n=180) of them were in the third decade. Fall from height remained the most common cause (n=230, 52.3%). Two hundred sixty (59.1%) patients reported within 48 hours. Thirty-two (7.27%) patients had single transfer, and all 32 showed complete independence for mobility at final followup. 100 of 260 (38.5%) patients reporting within 48 hours developed pressure sores, while 114 of 142 (80.28%) patients reporting after 5 days developed pressure sores. Conclusion: The present study highlights the magnitude of the problems of our trauma-care and transport system and the difference an effective system can make in the care of spinal injury patients. There is an urgent need for epidemiological data on a larger scale to emphasize the need for a better trauma-care system and pave way for adaptation of well-established trauma-care systems from developed countries.

Staged Anterior Release and Posterior Instrumentation in Correction of Severe Rigid Scoliosis (Cobb Angle >100 Degrees)

PURPOSE Severe rigid curves present a big challenge to the treating spine surgeon. We evaluated the outcome of staged anterior release and posterior instrumentation for rigid scoliosis. METHODS Twenty-one patients with an average age of 14.4 years (range 11-17) having a rounded severe rigid scoliosis (Cobb angle >100 degrees) underwent surgical correction. Six patients had congenital scoliosis, 13 idiopathic scoliosis, and 2 syndromic. All patients underwent anterior release in Stage I with one or more Ponte osteotomies and in Stage II with all pedicle screw instrumentation, and 13 of the patients underwent an asymmetric pedicle subtraction osteotomy at the apex. Patients were assessed for deformity correction, operative time, blood loss, and any complications. RESULTS The preoperative Cobb angle of 116.6 degrees (range 101-124 degrees) improved to 74.0 degrees (range 54-86 degrees) after anterior release: 29.4% correction and the final postoperation Cobb angle after posterior instrumentation was 26.5 degrees (range 22-32 degrees), with final 76% correction. The average blood loss in anterior release was 585.95 mL (range 400-980 mL; % estimated blood volume = 19.5%), whereas the mean operative time was 223 minutes (165-315 minutes). One patient had prolonged chest drain and two, basal atelectasis following anterior release. The mean operative time for the posterior procedure was 340 minutes (range 280-420 minutes) and average blood loss was 2,066 mL (range 1,200-3,200 mL). The mean apical axial rotation of 56 degrees (range 26-79 degrees) improved to 28 degrees (range 9-42 degrees) (p < .05). There was loss of motor evoked potential signal in one and hook pullout, superficial infection, and local skin necrosis one case each. CONCLUSION The staged approach to the management of severe, rigid scoliosis helps get an excellent correction. Anterior release loosens up the rigid apex and provides with nearly 30% correction so that the extent of the osteotomies in the second stage from the back is substantially reduced, allowing for a final good correction.

Emphysematous Osteomyelitis - A Rare Cause of Gas in Spine - A Case Report

Emphysematous osteomyelitis is rare condition characterised by the presence of intraosseous gas. About 25 such cases have been reported in the literature with only 10 cases involving spine. These infections are commonly seen in elderly morbid patients and are highly fatal. We report a 65 year old female patient with history of sudden onset of back pain and weakness of both the lower limbs with radiological images revealing the features of emphysematous osteomyelitis of L5 vertebra, which was treated with surgical decompression and stabilisation, and post-operative antibiotics. We also review literature to describe the clinical and radiological features for diagnosis and the treatment options available for such infections.

Perforations and angulations of 324 cervical medial cortical pedicle screws: a possible guide to avoid lateral perforations with use of pedicle screws in lower cervical spine

BACKGROUND CONTEXT More than half of the perforations reported with usage of cervical pedicle screws (CPS) are lateral perforations, endangering the vertebral artery. The medial cortical pedicle screw (MCPS) technique with partial drilling of the medial cortex shifts the trajectory of pedicle screws medially, decreasing the lateral perforations. PURPOSE To evaluate the decrease in lateral perforations of CPS with use of MCPS technique, in relation to medial angulation. STUDY DESIGN/SETTING Retrospective analysis and technical report of the MCPS technique and its safety. PATIENT SAMPLE A total of 58 patients operated on between December 2011 and May 2015 with insertion of pedicle screws from C3 to C7 were included in the study. OUTCOME MEASURES Axial reconstructed computed tomography (CT) scan images of the inserted screws were evaluated for placement, perforations, and transverse plane angulations using the Surgimap software (Surgimap Spine 1.1.2.271 Intl. 2009 Nemaris LLC). The angulations of screws were analyzed by the type and level of placement through unpaired t test and analysis of variance test. METHODS A total of 58 patients operated on between December 2011 and May 2015 with insertion of pedicle screws from C3 to C7 were included in the study. There were 49 males and 9 females. Thirty-seven patients had cervical trauma, 17 had cervical spondylotic myelopathy, two had tumors, and two had ankylosing spondylitis. The average age was 49 years (range 18 to 80 years). The screws were inserted using the MCPS technique. All patients underwent postoperative CT scans with GE Optima CT540 16 slice CT scanner (GE Healthcare Chalfont St. Giles, Buckinghamshire, UK). Axial reconstructed images along the axis of the inserted screws were evaluated for placement and perforations. Further, all the screws were evaluated for transverse plane angulations using the Surgimap software. The angulations of screw were analyzed by the type and level of placement through unpaired t test and analysis of variance test. No funds were received by any of the authors for the purpose of the present study. RESULTS A total of 324 screws were assessed with postoperative CT scans. Two hundred fifty-six were found to be placed within the pedicle and 68 (20.98%) screws were found to have perforations. Forty screws (12.34%) had grade I medial perforations, 14 screws (4.32%) had grade I lateral perforations, 10 screws (3.08%) had grade II medial perforations, and 4 screws (1.23%) had grade IIlateral perforations. The average angulation of the nonperforated screws (n=256) was 28.6° (43°-17°), that of laterally perforated screws was 20.33° (13°-24°), and that of the medially perforated screws was 34.94° (45°-20°). On statistical analysis with each series, the 99% CI range for the in-screw angles was 27.91° to 29.34°; for the laterally perforated screw series, it was 18.42° to 22.23°; and that for the medially perforated screw series was 32.97° to 36.9°. CONCLUSIONS The MCPS technique represents a shift in the concept of placement of CPS from the cancellous core to the medial cortex, avoiding screw deflection laterally by the thick proximal medial cortex. The present study shows that the lateral perforations can be consistently avoided, with a medial angulation of more than 27.91°, which is the primary concern with the use of pedicle screws in lower cervical spine. Further, the MCPS technique reduces the lateral perforations at a lesser insertion angle, which is technically desirable.

Complication rate during multilevel lumbar fusion in patients above 60 years

Background: Spine surgery in elderly with comorbidities is reported to have higher complication rates and increased cost. However, the surgical outcome is good irrespective of the complications. Hence, it is essential to identify the factors affecting the complication rates in such patients and the measures to reduce them. This retrospective observational study determines the perioperative complications, their incidence and the measures to reduce complications in the elderly with comorbidities, operated by instrumented multilevel lumbar fusion. Materials and Methods: Patients aged 60 years and above with one or more comorbidities operated by multilevel instrumented lumbar fusion in our center between January 2012 and December 2013 were included in the study. Perioperative complications and their incidence were calculated. Age, number of levels fused, operative time, blood loss, and complication rates were correlated with the duration of stay and the incidence of perioperative complications using SPSS software. Measures to reduce complications are determined by these results and by review of literature. Results: Fifty two patients were included in the study (28 females and 24 males) with an average age of 69 years (range 60-84 years). Hypertension was the most common comorbidity followed by diabetes. Spondylolisthesis was the most common indication. Eleven complications were noted with an incidence of 21%. Three were systemic complications which required transfer to Intensive Care Unit. Local complications were incidental durotomy (three), transient root deficits (two), wound infections (one), and persistent radicular pain (two). Operative time and blood loss were significantly higher in patients with complications. Conclusion: Complication rates strongly correlate with the blood loss and operative time. Reducing the operative time and blood loss by intraoperative tranexamic acid, laminectomy using osteotome, simultaneous bilateral exposure and instrumentation and reducing the number of interbody fusions can help in reducing the complications.