Management of rigid post-traumatic kyphosis

How to Optimize Pedicle Screw Parameters for the Thoracic Spine? A Biomechanical and Finite Element Method Study

STUDY DESIGN

Pedicle screw study.

OBJECTIVE

The selection of pedicle screw parameters usually involves the surgeon's analysis of preoperative CT imaging along with anatomical landmarks and tactile examination. However, there is minimal consensus on a standardized guideline for selection methods on pedicle screws. We aimed to determine the effects of thoracic screw diameter to pedicle width on pullout strength determined by cortical bone purchase.

METHODS

Biomechanical study performed with human cadaveric thoracic vertebrae and experimentally validated three-dimensional finite element model instrumented with pedicle screws of various diameters. We used a variable (SD/PW) ratio to express the screw selection. We hypothesized a positive correlation between the pullout load determined by the bone purchase and the SD/PW. This relationship was first investigated in a validated finite element model considering bone purchase related to the strength of an upper thoracic vertebra. Then, the correlation to the entire spine is evaluated.

RESULTS

The failure load ranged from 371.3 to 1601.0 N, respectively, for 3 and 6 mm screws. The determinant coefficient was increased to R2=.421 when a linear relationship between pullout load and the SD/PW ratio was used. The peak loads of 1216 and 1288N were found for an SD/PW ratio of .83.

CONCLUSION

We have found that the screw pullout load is more correlated to SD/PW than other pedicle measures for a maximized SD/PW ratio of .83. This particular value should be considered the upper limit of the indicated SD/PW ratio and a means to determine the optimal screw diameter to enhance pullout strength.

The Current Status of Spinal Posttraumatic Deformity: A Systematic Review

STUDY DESIGN

Systematic Review.

OBJECTIVE

To systematically analyze the definitions and descriptions in literature of "Spinal Posttraumatic Deformity" (SPTD) in order to support the development of a uniform and comprehensive definition of clinically relevant SPTD.

METHODS

A literature search in 11 international databases was performed using "deformity" AND "posttraumatic" and its synonyms. When an original definition or a description of SPTD (Patient factors, Radiological outcomes, Patient Reported Outcome Measurements and Surgical indication) was present the article was included. The retrieved articles were assessed for methodological quality and the presented data was extracted.

RESULTS

46 articles met the inclusion criteria. "Symptomatic SPTD" was mentioned multiple times as an entity, however any description of "symptomatic SPTD" was not found. Pain was mentioned as a key factor in SPTD. Other patient related parameters were (progression of) neurological deficit, bone quality, age, comorbidities and functional disability. Various ways were used to determine the amount of deformity on radiographs. The amount of deformity ranged from not deviant for normal to >30°. Sagittal balance and spinopelvic parameters such as the Pelvic Incidence, Pelvic Tilt and Sacral Slope were taken into account and were used as surgical indicators and preoperative planning. The Visual Analog Scale for pain and the Oswestry Disability Index were used mostly to evaluate surgical intervention.

CONCLUSION

A clear-cut definition or consensus is not available in the literature about clinically relevant SPTD. Our research acts as the basis for international efforts for the development of a definition of SPTD.

Transpedicular bi-vertebrae wedge osteotomy in treatment of post-tubercular spinal deformity: a retrospective study

Background

In the late stage of spinal tuberculosis, the bony destruction and vertebral collapse often leads to significant kyphosis, presenting clinically as a painful gibbus deformity, with increased instability, vertebral body translations and increased risk of neurologic involvement. Spinal osteotomy is thought to be suitable for most patients with severe rigid kyphosis. The aim of this study was to evaluate the efficacy of transpedicular bi-vertebrae osteotomy technique in the patients with Pott’s kyphosis and other post-tubercular spinal deformity.

Methods

Between January 2012 and December 2015, 18 patients with post-tubercular spinal deformity underwent the transpedicular bi-vertebrae wedge osteotomy, with a minimum follow up of 27.0 months. Preoperative and postoperative kyphotic angle, sagittal plane parameters (TK for thoracic deformity, TLK for thoracolumbar and LL for lumbar deformity) and sagittal vertical axis (SVA) were measured. Oswestry Disability Index (ODI), Visual analog scale (VAS) and modified American Spinal Injury Association grading (ASIA) of preoperative and final follow-up were documented and compared.

Results

The average operation time was 305 minutes (range, 200–430 minutes) with a mean intraoperative blood loss of 425 mL (range, 200-700 mL). The kyphotic angles decreased from 80.3° (range, 28.5°-130.8°) preoperatively to 26.1° (range, 7.0°-63.3°) at the final follow-up (P<0.01). The mean VAS score was reduced from preoperative 5.2(range, 2-9) to 0.9(range, 0-2, P<0.01) and the ODI improved from 55.3% (range, 46%-76%) to 6.3% (range, 2%-18%, P<0.01). At final follow-up, there was radiographic evidence of solid fusion at the osteotomy site and fixed segments in all patients. Neurological function improved from ASIA scale D to E in 7 patients, C to D in 3 patients.

Conclusions

Our results suggest that transpedicular bi-vertebrae wedge osteotomy is a safe and effective treatment option for post-tubercular spinal deformity. This technique achieves satisfying correction and fusion rates with adequate decompression of neurological elements.

Modified grade 4 osteotomy for the correction of post-traumatic thoracolumbar kyphosis: A retrospective study of 42 patients

Many surgical procedures have been developed for the treatment of post-traumatic thoracolumbar kyphosis. But there is a significant controversy over the ideal management. The aim of this study was to illustrate the technique of modified grade 4 osteotomy for the treatment of post-traumatic thoracolumbar kyphosis and to evaluate clinical and radiographic results of patients treated with this technique.From May 2013 to May 2018, 42 consecutive patients experiencing post-traumatic thoracolumbar kyphosis underwent the technique of modified grade 4 osteotomy, and their medical records were retrospectively collected. Preoperative and postoperative sagittal Cobb angle, visual analog scale (VAS), Oswestry disability index (ODI), and American Spinal Injury Association (ASIA) were recorded. The average follow-up period was 29.7 ± 14.2 months.The operation time was 185.5 ± 26.8 minutes, the intraoperative blood loss was 545.2 ± 150.1 mL. The Cobb angles decreased from 38.5 ± 3.8 degree preoperatively to 4.2 ± 2.6 degree 2 weeks after surgery (P < .001). The VAS reduced from 6.5 ± 1.1 preoperatively to 1.5 ± 0.9 at final follow-up (P < .001), and the ODI reduced from 59.5 ± 15.7 preoperatively to 15.9 ± 5.8 at final follow-up (P < .001). Kyphotic deformity was successfully corrected and bony fusion was achieved in all patients. Neurologic function of 7 cases was improved to various degrees.Modified grade 4 osteotomy, upper disc, and upper one-third to half of pedicle are resected, is an effective treatment option for post-traumatic thoracolumbar kyphosis. However, the long-term clinical effect still needs further studies.

A limited unilateral transpedicular approach for anterior decompression of the thoracolumbar spinal cord in elderly and high-risk patients

Background:

Surgical treatment for elderly patients with thoracolumbar (TL) kyphosis and spinal cord (SC) compression presents significant challenges due to compression location, the amount of deformity, and patient's medical status might not permit full correction of the deformity. In this series, we present a surgical approach that provides adequate decompression without the risks associated with a pedicle subtraction osteotomy/posterior vertebral column resection or an anterior corpectomy.

Methods:

Three patients presented with TL kyphosis and progressive neurologic symptoms. All had acute weakness; none were ambulatory. SC was compressed over the apex of kyphosis, and for some, there was spinal stenosis at the proximal junction of the TL spine. The surgical technique involved unilateral resection of the pars, pedicles, the posterior one-third of the lateral wall of the vertebral body, decancellation of the impinging kyphus, and finally resection of the posterior vertebral body wall compressing the SC followed by instrumentation and fusion two levels above and below the fused segments.

Results:

All patients survived the procedure and left the hospital after 10–22 days. Estimated blood loss was 653 ml. No deep infections occurred. One patient developed acute tubular necrosis but recovered fully. The other two showed improvement of one Frankel grade and were independent in the final follow-up. One patient developed acute tubular necrosis but recovered fully yet his neurologic status was unchaged. The other two showed improvement of one Frankel grade and were independent in the final follow-up.

Conclusion:

The procedure described presents a compromise that fits the more elderly patient that might not be able to tolerate major deformity correction and at the same time provides similar results in the short and medium term to more extensive procedures.

Early Lumbar Nerve Root Deficit After Three Column Osteotomy for Fixed Sagittal Plane Deformities in Adults

Background

Three-column osteotomy is an effective means of correcting fixed sagittal plane deformities. Deformity correction surgeries may be associated with early postoperative neurological deficits often presenting as palsies involving the lumbar roots. The objective was to retrospectively assess a subset of our series of adult deformity correction surgeries and analyze neurological deficits and associated patient and surgical factors.

Methods

Hospital records of 17 patients from a single center were examined. Inclusion criterion were adults (>18 years) who underwent a 3-column osteotomy (pedicle subtraction osteotomy) at the lumbar level for fixed sagittal plane deformities including positive sagittal balance, flat back syndrome, and posttraumatic kyphosis. These also included cases with associated degenerative lumbar scoliosis. Patients were divided in 2 groups: Group 1 with lumbar root deficit and Group 2 with no deficits. We examined the surgical details of the osteotomy, complications during surgery, and observed if the magnitude of correction in the sagittal or coronal plane bore any influence on the nerve deficit.

Results

All 17 patients had a single-level resection except 1 patient who had 2-level osteotomy; 23.5% (4 of 17) developed nerve deficit. Nerve deficit presented as bilateral foot drop (1); unilateral extensor hallucis longus (EHL) weakness (2); and unilateral quadriceps weakness (1). The patient with quadriceps weakness partially recovered to functional strength. Two patients with EHL weakness fully recovered; however, the patient with bilateral foot drop did not improve. L5-S1 interbody fusion was done in 3 of 4 cases in Group 1 and 4 of 13 cases in Group 2.

Conclusions

Nerve deficits after 3-column corrective osteotomies occurred in 23% cases. All but 1 case had significant improvement. Most nerve palsies are neuropraxia and unilateral and tend to recover. L5 weakness appears most common after high lumbar osteotomies. Significant correction of scoliosis at the osteotomy level (>50%) may be a reason for nerve palsy.

Clinical outcome and surgical strategies for late post-traumatic kyphosis after failed thoracolumbar fracture operation: Case report and literature review

RATIONALE

Thoracic-lumbar vertebral fracture is very common in clinic, and late post-traumatic kyphosis is the main cause closely related to the patients' life quality, which has evocated extensive concern for the surgical treatment of the disease. This study aimed to analyze the clinical outcomes and surgical strategies for late post-traumatic kyphosis after failed thoracolumbar fracture operation.

PATIENT CONCERNS

All patients presented back pain with kyphotic apex vertebrae between T12 and L3. According to Frankel classification grading system, among them, 3 patients were classified as grade D, with the ability to live independently.

DIAGNOSES

A systematic review of 12 case series of post-traumatic kyphosis after failed thoracolumbar fracture operation was involved.

INTERVENTIONS

Wedge osteotomy was performed as indicated-posterior closing osteotomy correction in 5 patients and anterior open-posterior close correction in 7 patients.Postoperatively, thoracolumbar x-rays were obtained to evaluate the correction of kyphotic deformity, visual analog scales (VAS) and Frankel grading system were used for access the clinical outcomes.

OUTCOMES

All the patients were followed up, with the average period of 38.5 months (range 24-56 months). The Kyphotic Cobb angle was improved from preoperative (28.65 ± 11.41) to postoperative (1.14 ± 2.79), with the correction rate of 96.02%. There was 1 case of intraoperative dural tear, without complications such as death, neurological injury, and wound infection. According to Frankel grading system, no patient suffered deteriorated neurological symptoms after surgery, and 2 patients (2/3) experienced significant relief after surgery. The main VAS score of back pain was improved from preoperative (4.41 ± 1.08) to postoperative (1.5 ± 0.91) at final follow-up, with an improvement rate of 65.89%.

LESSONS

Surgical treatment of late post-traumatic kyphosis after failed thoracolumbar fracture operation can obtain good radiologic and clinical outcomes by kyphosis correction, decompression, and posterior stability.

Pedicle subtraction osteotomy and disc resection with cage placement in post-traumatic thoracolumbar kyphosis, a retrospective study

Background

It is estimated that upwards of 50,000 individuals suffer traumatic fracture of the spine each year, and the instability of the fractured vertebra and/or the local deformity results in pain and, if kyphosis increases, neurological impairment can occur. There is a significant controversy over the ideal management. The purpose of the study is to present clinical and radiographic results of pedicle subtraction osteotomy and disc resection with cage placement in correcting post-traumatic thoracolumbar kyphosis.

Methods

From May 2010 to May 2013, 46 consecutive patients experiencing post-traumatic thoracolumbar kyphosis underwent the technique of one-stage pedicle subtraction osteotomy and disc resection with cage placement and long-segment fixation. Pelvic incidence (PI), pelvic tilt (PT), sagittal vertical axis (SVA), and sagittal Cobb angle were measured to evaluate the sagittal balance. Oswestry disability index (ODI), visual analog scale (VAS), and general complications were recorded.

Results

The average surgical time was 260 min (240–320 min). The mean intraoperative blood loss was 643 ml (400–1200 ml). The maximum correction angle was 58° with an average of 47°, and the SVA improved from +10.7 ± 3.5 cm (+7.2 to + 17.1 cm) to +4.1 ± 2.7 cm (+3.2 to + 7.6 cm) at final follow-up (p < 0.01). PT reduced from preoperative 27.2 ± 5.3° to postoperative 15.2 ± 4.7° (p < 0.01). The VAS changed from preoperative 7.8 ± 1.6 (5.0–9.0) to 3.2 ± 1.8 (2.0–5.0) (p < 0.01). Clinical symptoms and neurological function were significantly improved at the final follow-up. All patients completed follow-up of 41 months on average.

Conclusions

Pedicle subtraction osteotomy and disc resection with cage placement and long-segment fixation are effective and safe methods to treat thoracolumbar post-traumatic kyphosis.

Modified closing-opening wedge osteotomy for the treatment of sagittal malalignment in thoracolumbar fractures malunion

BACKGROUND CONTEXT

Many techniques have been described for the surgical treatment of rigid posttraumatic thoracolumbar kyphosis, but none is well adapted to the modified shape of the wedged vertebra.

PURPOSE

The study aimed to describe the modified closing-opening wedge osteotomy (MCOWO), a new osteotomy technique that adapts to the triangular shape of the wedged apical vertebra of the deformity.

STUDY DESIGN

A retrospective assessment of the degree of correction before and after the MCOWO was carried out.

PATIENT SAMPLE

Ten patients presenting rigid posttraumatic thoracolumbar kyphosis were enrolled in this study.

OUTCOME MEASURES

We used preoperative and postoperative whole spine radiographs to assess the sagittal plane parameters, and computed tomography scan for measurement of the vertebral segment height at the osteotomy level, spinal cord length, aorta length, and fusion rate.

METHODS

Ten patients underwent the MCOWO at T12 or L1. The procedure involves removing the postero-superior triangular corner of the wedged vertebra and transforming it to a shape similar to a trapezoid.

RESULTS

The patients' mean age was 36.6±7.5 years, the mean time between the fracture and the surgery was 12.2±5.6 months, and the mean follow-up was 30.6±5 months. In all patients, statistically significant improvement was observed in the sagittal plane after surgery. The thoracolumbar angle improved from 52±6° preoperatively to 7.1±5.7° at the last follow-up. Mean osteotomy angle was 38.1±2.6°, mean spinal cord shortening was 1.2±0.2 cm, and mean aorta lengthening was 2.3±0.4 cm. All the patients showed complete fusion at 2 years, and none required revision surgery. Two patients presented a temporary unilateral weakness that recovered completely within 3 months after the surgery.

CONCLUSIONS

The MCOWO is an interesting procedure for patients with posttraumatic thoracolumbar kyphosis. The modified osteotomy is adapted to the modified shape of the compressed vertebra. Spinal cord shortening and aorta lengthening were well tolerated in all patients.

Clinical and radiological outcomes of modified posterior closing wedge osteotomy for the treatment of posttraumatic thoracolumbar kyphosis

OBJECT

Most thoracolumbar fractures have a good healing outcome with adequate treatment. However, posttraumatic thoracolumbar kyphosis can occur in a proportion of thoracolumbar fractures after inappropriate treatment, osteoporosis, or osteonecrosis of the vertebral body. There are several surgical options to correct posttraumatic thoracolumbar kyphosis, including anterior, posterior, and combined approaches, which are associated with varying degrees of success. The aim of this study was to assess the use of a modified closing wedge osteotomy for the treatment of posttraumatic thoracolumbar kyphosis and to evaluate the radiographic findings and clinical outcomes of patients treated using this technique.

METHODS

Thirteen consecutive patients with symptomatic posttraumatic thoracolumbar kyphosis were treated using a modified closing wedge osteotomy. The mean patient age was 62 years. The kyphosis apex ranged from T-10 to L-2. The sagittal alignment, kyphotic angle, neurological function, visual analog scale for back pain, and Oswestry Disability Index were evaluated before surgery and at follow-up.

RESULTS

The mean preoperative regional angle was 27. 4°, and the mean correction angle was 29. 6°. Sagittal alignment improved with a mean correction rate of 58. 3%. The mean surgical time was 275 minutes, and the mean intraoperative blood loss was 1585 ml. The intraoperative complications included 2 dural tears, 1 nerve root injury, and 1 superficial wound infection. The mean visual analog scale score for back pain improved from 6. 6 to 2, and the Oswestry Disability Index score decreased from 55. 4 to 22. 6 at the last follow-up. All patients achieved bony anterior fusion based on the presence of trabecular bone bridging at the osteotomy site.

CONCLUTIONS

The modified posterior closing wedge osteotomy technique achieves satisfactory kyphosis correction with direct visualization of the circumferentially decompressed spinal cord, as well as good fusion with less blood loss and fewer complications. It is an alternative method for treating patients with posttraumatic thoracolumbar kyphosis.

Anterior D-rod and titanium mesh fixation for acute mid-lumbar burst fracture with incomplete neurologic deficits: A prospective study of 56 consecutive patients

BACKGROUND

Anterior decompression and reconstruction have gained wide acceptance as viable alternatives for unstable mid-lumbar burst fracture, but there are no mid and long term prospective studies regarding clinical and radiologic results of mid-lumbar burst fractures.

MATERIALS AND METHODS

An Institutional Review Board-approved prospective study of 56 consecutive patients of mid-lumbar burst fractures with a load-sharing score of 7 or more treated with anterior plating was carried out. All patients were evaluated for radiologic and clinical outcomes. The fusion status, spinal canal compromise, segmental kyphotic angle (SKA), vertebral body height loss (VBHL), and adjacent segment degeneration was examined for radiologic outcome, whereas the American Spinal Injury Association scale, the visual analog scale (VAS), and the employment status were used for clinical evaluation.

RESULTS

The patients underwent clinical and radiologic followup for at least 5 years after the surgery. At the last followup, there was no case of internal fixation failure, adjacent segment degeneration, and other complications. Interbody fusion was achieved in all cases. The average fusion time was 4.5 months. No patient suffered neurological deterioration and the average neurologic recovery was 1.3 grades on final observation. Based on VAS pain scores, canal compromise, percentage of VBHL and SKA, the difference was statistically significant between the preoperative period and postoperative or final followup (P < 0.05). Results at postoperative and final followup were better than the preoperative period. However, the difference was not significant between postoperative and final followup (P > 0.05). Thirty-four patients who were employed before the injury returned to work after the operation, 15 had changed to less strenuous work.

CONCLUSION

Good mid term clinicoradiological results of anterior decompression with D-rod and titanium mesh fixation for suitable patients with mid-lumbar burst fractures with incomplete neurologic deficits can be achieved. The incident rate of complications was low. D-rod is a reliable implant and has some potential advantages in L4 vertebral fractures.

Percutaneous pedicle screw placement in the thoracic spine: A cadaveric study

STUDY DESIGN

A cadaveric study to determine the accuracy of percutaneous screw placement in the thoracic spine using standard fluoroscopic guidance.

SUMMARY OF BACKGROUND DATA

While use of percutaneous pedicle screws in the lumbar spine has increased rapidly, its acceptance in the thoracic spine has been slower. As indications for pedicle screw fixation increase in the thoracic spine so will the need to perform accurate and safe placement of percutaneous screws with or without image navigation. To date, no study has determined the accuracy of percutaneous thoracic pedicle screw placement without use of stereotactic imaging guidance.

MATERIALS AND METHODS

Eighty-six thoracic pedicle screw placements were performed in four cadaveric thoracic spines from T1 to T12. At each level, Ferguson anterior-posterior fluoroscopy was used to localize the pedicle and define the entry point. Screw placement was attempted unless the borders of the pedicle could not be delineated solely using intraoperative fluoroscopic guidance. The cadavers were assessed using pre- and postprocedural computed tomography (CT) scans as well as dissected and visually inspected in order to determine the medial breach rate.

RESULTS

Ninety pedicles were attempted and 86 screws were placed. CT analysis of screw placement accuracy revealed that only one screw (1.2%) breached the medial aspect of the pedicle by more than 2 mm. A total of four screws (4.7%) were found to have breached medially by visual inspection (three Grade 1 and one Grade 2). One (1.2%) lateral breach was greater than 2 mm and no screw violated the neural foramen. The correlation coefficient of pedicle screw violations and pedicle diameter was found to be 0.96.

CONCLUSIONS

This cadaveric study shows that percutaneous pedicle screw placement can be performed in the thoracic spine without a significant increase in the pedicle breach rate as compared with standard open techniques. A small percentage (4.4%) of pedicles, especially high in the thoracic spine, may not be safely visualized.

Efficiency of ligamentotaxis using PLL for thoracic and lumbar burst fractures in the load-sharing classification

The use of pedicle screws for short-segment implants has been known to be dangerous in patients who score a 7 or higher on McCormack's classification. The efficiency of ligamentotaxis of the posterior longitudinal ligament (PLL) and short-segment implants and fusion in relation to McCormack's classification has not been proven. The purpose of this study was to compare the clinical and radiological results of indirect decompression using PLL ligamentotaxis between patients with a high- (score of 7 or higher) or low-grade (score of 6 or less) fracture. Eighteen patients (19 levels) in the low-grade fracture group were compared with 23 patients (27 levels) in the high-grade fracture group. Clinical outcomes were measured using the Oswestry Disability Index (ODI) and visual analog scale (VAS) scores; radiologic measures were determined using the spinal canal area and mean sagittal diameter; and the complications were evaluated and compared. A significant improvement in each groups was found in the mean pre- and postoperative spinal canal area, mean sagittal diameter, Cobb's angle, and anterior vertebral height compression rate. A significant difference was found between the 2 groups in the mean pre- and postoperative spinal canal area, mean sagittal diameter, and anterior vertebral height compression rate. Moreover, the VAS and ODI scores continued to significantly improve at the last follow-up in each group. No difference was found in the prevalence of complications. Despite a high score, no significant difference was found in the clinical and radiological results and the complications. Therefore, indirect decompression using PLL ligamentotaxis was found to be a useful technique for patients who recieve a high McCormack's classification score.

Parafusos pediculares: estruturas anatômicas em risco no tratamento da escoliose idiopática

OBJETIVO: Avaliar a posição das estruturas anatômicas em risco durante a inserção de parafusos pediculares na coluna torácica e sua relação com a variação do ângulo de Cobb. MÉTODOS: Os parâmetros estudados foram: a medida do ângulo de Cobb nas radiografias e a posição da medula espinhal, da cavidade pleural e aorta na ressonância nuclear magnética em relação a uma linha de 40mm criada para simular o parafuso pedicular nas cinco vértebras apicais. RESULTADOS: A distância da aorta ao corpo vertebral e o ângulo de segurança do lado convexo apresentaram diferença estatística quando relacionados com a variação do ângulo de Cobb medido. CONCLUSÃO: Os resultados apresentados sugerem maior risco de lesão da artéria aorta com o aumento do ângulo de Cobb e aumento do risco na inserção de parafusos pediculares no lado convexo da curvatura, quando se considera o ângulo de segurança.

Post-traumatic deformity: prevention and management

Traumatic spinal column injuries (SCI) can result in devastating deformities that often have long-term impact on the patient's quality of life. These deformities result in pain and occasionally neurological deficits. The deformities affecting adults often differ slightly from those in the pediatric population. In adults, injuries to the spinal column frequently result in a sagittal plane deformity, such as kyphosis or lordosis. However, in children, spinal cord injuries often cause coronal deformities, such as scoliosis. Patients with post-traumatic spinal column deformities may present acutely immediately after the injury, many years after the inciting event, or at any time in-between. Patients with post-traumatic spinal deformity initially complain of pain at the site of the deformity, but with time may complain of pain above or below the deformity as a result of degenerative changes. Any change or worsening of neurological status is a worrisome complaint, and often these patients require surgical intervention. Procedures such as fusions and spinal column osteotomies have shown promising results in treating patients with post-traumatic spinal deformities and have been shown to improve their quality of life.

Simultaneous posterior and anterior approaches with posterior vertebral wall preserved for rigid post-traumatic kyphosis in thoracolumbar spine

STUDY DESIGN

A retrospective study.

OBJECTIVE

To evaluate the radiological and clinical results of simultaneous surgery with preservation of the posterior vertebral wall for rigid post-traumatic kyphosis in the thoracolumbar spine.

SUMMARY OF BACKGROUND DATA

Management of rigid post-traumatic kyphosis has been a challenge for surgeons. Current widely used posterior osteotomy procedures have the disadvantages of significant invasiveness, spinal column shortening, and instrumentation-related complications.

METHODS

From 2004 to 2009, 21 patients with rigid post-traumatic kyphosis in the thoracolumbar spine (T11-L2) were managed in our hospital. Average kyphotic angle was 45.2° ± 11.2° (range, 31°-67°). The surgical technique used was posterior and anterior circumferential release and anterior corpectomy with posterior vertebral wall preservation and short segmental instrumentation. Preoperative and postoperative kyphotic angle was measured to assess the degree of kyphosis correction and maintenance. Changes in low back pain were assessed by Japanese Orthopaedic Association scores.

RESULTS

All patients were successfully managed with this procedure without major complications. Most patients (19 of 21) were instrumented with anterior-only fixation, while posterior interspinal wire was added in 2 patients with osteoporosis. The mean blood loss was 470 mL (range, 300-700 mL). Patients were followed for an average of 32 months (range, 6-70 mo) postoperatively. Back pain was relieved to some degree in all patients and the improvement in Japanese Orthopaedic Association scores was 76.9% ± 7.9. Average kyphotic angle was 6.0° ± 5.7° (range, -2 to 17) immediately after surgery and 7.2° ± 5.8° (range, -3 to 17) at final follow-up. Average of 1° of correction loss was documented and all patients obtained solid fusion uneventfully.

CONCLUSION

This technique is indicated for most patients with rigid post-traumatic kyphosis in the thoracolumbar spine and can yield satisfactory clinical results not only in terms of pain relief, kyphosis correction, vertebral height restoration, and spinal canal integrity preservation, but also in reducing the risk of excessive bleeding and spinal cord injury.

Anterior versus posterior approach in the treatment of chronic thoracolumbar fractures

The purpose of this study was to compare the results of anterior approach vs posterior approach in the treatment of chronic thoracolumbar fractures. A total of 36 patients with chronic thoracolumbar fractures were divided into 2 groups. Group A was treated by an anterior approach and group B was treated by a posterior approach. During the minimum 24-month follow-up period (range, 24-62 months), all patients were prospectively evaluated for clinical and radiologic outcomes. Intraoperative blood loss, operative time, operative complications, pulmonary function, Frankel scale, and American Spinal Injury Association (ASIA) motor score were used for clinical evaluation, and Cobb angle was examined for radiologic outcome. All patients in this study achieved solid fusion, with significant neurologic improvement. Operative time, perioperative blood loss, ASIA score on admission and at final follow-up, and complications of respiratory tract infection and intercostal nerve pain were not significantly different between the 2 groups (P>.05), but complications of hemopneumothorax, abdominal distension, and constipation were fewer in group B (P<.05). Postoperative pulmonary function (P<.05) and correction of posttraumatic kyphosis were better in group B (P<.05).

Comparison between pedicle subtraction osteotomy and anterior corpectomy and plating for correcting post-traumatic kyphosis: a multicenter study

Kyphosis is a common sequel of inadequately managed thoracolumbar fractures. This study compares between pedicle subtraction osteotomy (PSO) and anterior corpectomy and plating (ACP) for correcting post-traumatic kyphosis. Forty-three patients with symptomatic post-traumatic kyphosis of the thoracolumbar spine were treated with PSO and prospectively followed for a minimum of 2 years. Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) were used to assess clinical improvement and radiographs were obtained at 2, 6, 12 and 24 months. The recorded clinical and radiological outcomes were compared to a control group of 37 patients, who were treated earlier by the same authors with ACP. The mean correction of the kyphotic angle was 29.8° for the PSO group and 22° for the ACP group (P = 0.001). PSO group showed significantly better improvement in the VAS score and the ODI. At final follow-up, patients reported very good satisfaction (93% in PSO vs. 81% in ACP) and good function (90% in PSO vs. 73% in ACP). Complications in the PSO group included pulling out of screws and recurrence of deformity requiring revision and longer fixation (1 patient), and transient lower limb paraesthesia (2 patients). Recorded complications in the ACP group included an aortic injury (1 patient) that was successfully repaired, pseudarthrosis (1 patient), persistent graft donor site morbidity (3 patients), and incisional hernia (1 patient). PSO and ACP are demanding procedures. PSO seems to be equally safe but more effective than ACP for correcting post-traumatic kyphosis.

[Imaging features of post-traumatic spine and cord lesions]

The imaging evaluation of post-traumatic spine and cord injuries is part of the global management of chronically handicapped patients. Diagnosis and follow-up MR imaging of cord lesions allows differentiation of static lesions from progressive lesions that could require surgical intervention. Follow-up CT imaging is helpful in the evaluation of spine lesions to distinguish between late complications (deformity, malunion, pseudoarthrosis, complications related to surgical hardware) and lesions secondary to the handicap (neurogenic spinal arthropathy).

Alignment of pedicle screws with pilot holes: can tapping improve screw trajectory in thoracic spines?

Pedicle screws are placed using pilot holes. The trajectory of pilot holes can be verified by pedicle sounding or radiographs. However, a pilot hole alone does not insure that the screw will follow the pilot hole. No studies have characterized the risk of misalignment of a pedicle screw with respect to its pilot hole trajectory. The objective of this study was to measure the misalignment angles between pedicle screws and pilot holes with or without tapping. Six human cadaveric thoracic spines were used. One hundred and forty pilot holes were created with a straight probe. Steel wires were temporarily inserted and their positions were recorded with CT scans. The left pedicles were tapped with 4.5 mm fluted tap and the right pedicles remained untapped. Pedicle screws (5.5 mm) were inserted into the tapped and untapped pedicles followed by CT scans. The trajectories of pilot holes and screws were calculated using three-dimensional vector analysis. A total of 133 pilot holes (95%) were inside pedicles. For the untapped side, 14 out of 68 (20%) screws did not follow the pilot holes and were outside the pedicles. For the tapped side, 2 out of 65 (3%) did not follow and breached the pedicles. The average misalignment angles between the screw and pilot hole trajectory were 7.7 degrees +/- 6.5 degrees and 5.6 degrees +/- 3.2 degrees for the untapped side and tapped side, respectively (P < 0.05). Most pedicle screws had lateral screw breach (13 out of 16) whereas most pilot holes had medial pedicle breach (6 out of 7). Tapping of pilot holes (1 mm undertap) helps align pedicle screws and reduces the risk of screw malposition. Although most pedicle screws had lateral breach, the risk of medial pedicle breach of the pilot holes must be recognized.

Delayed posttraumatic thoracolumbar spinal deformities: diagnosis and management

Approximately 50,000 traumatic injuries resulting in fractures of the bony spinal column occur annually in the United States. Although some of these lesions are clearly unstable and mandate urgent surgical treatment for stabilization, less severe injuries may be managed initially with bracing and serial imaging to evaluate bony healing and alignment. A proportion of these injuries will require delayed surgical intervention to correct a posttraumatic deformity. In addition, inadequate or ineffective acute spinal stabilization can also result in the progression of delayed spinal deformities. The management of these lesions is frequently complicated by scarring in the body cavities from the inciting trauma or any subsequent surgical interventions, epidural scar formation and spinal cord tethering, solid fusion into the deformed state, medical comorbidities associated with paralysis, and compromised spinal cord function. With these factors in mind, surgical management of these frequently kyphotic deformities can be performed via a posterior approach with osteotomies or a combined anterior approach and posterior procedures.

Surgical management of posttraumatic thoracolumbar kyphosis

BACKGROUND CONTEXT

Spine trauma is relatively common, and each year approximately 10,000 to 17,000 people in the United States will sustain a spinal cord injury and approximately 150,000 to 160,000 will fracture their spinal column. Posttraumatic spinal deformity is a common potential complication of spinal injury and poses one of the greatest challenges in spinal surgery.

PURPOSE

To provide a comprehensive and current review of posttraumatic deformity focusing on the epidemiology, clinical and radiographical presentation, treatment options, and prognosis.

STUDY DESIGN/SETTING

A thorough review of the English literature on the management of posttraumatic deformity was performed. Pertinent articles were identified by using PubMed and a review of publications by the American Academy of Orthopaedic Surgeons.

METHODS

Each article was reviewed, and findings were analyzed to formulate a concise review of current treatment methods for posttraumatic deformity.

RESULTS

Successful treatment of posttraumatic deformity is dependent on careful patient selection and appropriate surgical intervention, which should be considered in the presence of significant or increasing deformity, increasing back and/or leg pain, "breakdown" at levels above or below the deformity, pseudarthrosis or malunion, and increasing neurological deficit. The goals of surgery should be to decompress the neural elements if neurological claudication or a neurological deficit is present, to recreate normal sagittal contours and balance, and to optimize the chances for successful fusion; these goals can be achieved through an all-anterior, all-posterior, or a combined anterior/posterior approach assuming that close attention is paid to using the appropriate bone-grafting techniques, selecting technically sound segmental instrumentation, and providing appropriate biomechanical environment for maintenance of correction and successful fusion.

CONCLUSIONS

Posttraumatic spinal deformity is a common complication of spinal injury, and it is therefore essential for patients with vertebral column injuries to have a careful initial evaluation, close follow-up, and early intervention when needed. Once posttraumatic deformity is present, successful outcome is achievable assuming a thorough, systematic, and technically well-executed surgical intervention is performed.

Correction of Late Traumatic Thoracic and Thoracolumbar Kyphotic Spinal Deformities Using Posteriorly Placed Intervertebral Distraction Cages

Objective:

To assess the safety and stability of thoracic or thoracolumbar deformity correction from a solely posterior approach with placement of modular anterior cages and posterior segmental fixation in one operation.

Methods:

Twenty-eight patients who failed brace trial for 6 months or longer were included in the series. All patients had progressive neurological deficit and/or deformity progression at time of operation. All patients underwent a single operation in the prone position. Segmental fixation was accompanied by anterior column reconstruction using modular cages avoiding nerve root sacrifice. Stackable cages were used for high thoracic deformity. Deformity, Cobb angle, visual analog pain score, and x-ray evaluation of fusion ensued for mean follow-up period of 31 months.

Results:

Patients achieved a mean sagittal deformity correction of 13.3 degrees ± 7.4 standard deviation. Improved or maintained American Spinal Injury Association scores were noted in all patients. The mean time of operation was 334 minutes ± 85 standard deviation, or 6 to 7 hours. At a mean follow-up of 31 months (range, 12–36 mo), the following complications were noted: subsidence greater than 2.5 mm (n = 3), cage migration requiring revision (n = 1), brachial plexopathy from malpositioning (n = 1), and intraoperative cerebrospinal fluid leak managed via lumbar drain (n = 2). Plain and dynamic radiographic evidence of maintained deformity correction was noted in 27 patients.

Conclusion:

Delayed kyphotic deformity correction of the thoracolumbar spine is achieved via a posterior-only approach. At a mean follow-up period of 31 months, sagittal angles remained acceptable. Improved fusion criteria and patient numbers will be required to determine fusion and loss of correction rates over time.

Neurologic complications of lumbar pedicle subtraction osteotomy: a 10-year assessment

STUDY DESIGN

Clinical, radiographic, and outcomes assessment focusing on neurologic complications in patients undergoing pedicle subtraction osteotomy (PSO). Clinical data were collected prospectively. Radiographic analysis was performed retrospectively.

OBJECTIVE

To evaluate intraoperative and postoperative neurologic deficits following lumbar PSOs in order to determine risk factors, treatment strategies, and patient outcome.

SUMMARY OF BACKGROUND DATA

Although technically demanding, PSOs have been increasingly used to restore lumbar lordosis and correct sagittal deformity. Although some reports have commented on various complications of the procedure, to our knowledge, there have been no studies focusing on neurologic complications of the osteotomy.

METHODS

An analysis of 108 consecutive patients with an average age of 54.8 +/- 14.0 years and treated with a lumbar PSO at 1 institution over a 10-year period (1995-2005) was performed. Medical records, radiographs, and neuromonitoring data were analyzed. Clinical outcome was assessed using the Oswestry Disability Index and the Scoliosis Research Society (SRS)-24 instruments.

RESULTS

A total of 108 PSOs were performed. Following surgery, lumbar lordosis increased from -17.1 degrees +/- 19.3 degrees to -49.3 degrees +/- 14.7 degrees (P < 0.000), and sagittal balance improved from 131 +/- 73 mm to 23 +/- 48 mm (P < 0.000). Intraoperative and postoperative deficits (defined as motor loss of 2 grades or more or loss of bowel/bladder control) were seen in 12 patients (11.1%) and were permanent in 3 patients (2.8%). With time motor function improved by 1 grade in 2 patients and all 3 were able to ambulate. Intraoperative neuromonitoring did not detect the deficits. In 9 patients, additional surgical intervention consisted of central enlargement and further decompression. Deficits were thought to be due to a combination of subluxation, residual dorsal impingement, and dural buckling.

CONCLUSION

Intraoperative or postoperative neurologic deficits are relatively common following a PSO; however, in a majority of cases, deficits are not likely to be permanent.

Minimum 5-year follow-up surgical results of post-traumatic thoracic and lumbar kyphosis treated with anterior instrumentation: comparison of anterior plate and dual rod systems

STUDY DESIGN

A retrospective follow-up study of post-traumatic thoracic and lumbar kyphosis after anterior instrumentation with anterior plate and dual rod systems.

OBJECTIVE

To investigate the outcome of anterior vertebrectomy, anterior strut grafting, and anterior instrumentation in patients with > 30 degrees sagittal contour deformity.

SUMMARY OF BACKGROUND DATA

Post-traumatic kyphosis may lead to mechanical pain due to the impairment of physiologic sagittal contours as well as cosmetic complaints.

METHODS

Forty patients with post-traumatic kyphosis were followed for a minimum of 5 years. Mean age was 44.7 +/- 12.4 years (range, 18-65 years); 18 were female and 22 were male. All patients underwent anterior vertebrectomy and decompression; anterior fusion was carried out with costal or iliac ala grafts. Patients were randomly assigned into 2 treatment groups: correction and internal fixation was performed by using either plate-screw (n = 20) or double rod-screw (n = 20). Patients were also evaluated clinically by using Pain and Functional Assessment Scale (PFA) and SRS-22 questionnaire.

RESULTS

Before surgery, the mean value for local sagittal contours was 51.4 degrees +/- 13.8 degrees; after surgery, it was reduced to 7.0 degrees +/- 7.6 degrees, resulting in an 88.7% +/- 11.3% correction (P = 0.00). At the last follow-up visit, a mean correction loss of 1.4 degrees +/- 1.8 degrees was found. A statistically significant improvement in local kyphosis angles and PFA scores was found after surgery and at the last visit. In 92.5% of the patients (n = 36), pain completely resolved; and in the remaining 3 patients, it is markedly reduced. Neurologic improvement was achieved in all of the 24 patients with neural claudication and other neurologic findings. Solid fusion mass was obtained in all patients. The type of instrumentation system did not differ significantly in terms of kyphotic deformity correction rates, correction losses, PFA scores, and SRS-22 scores. Final PFA scores showed a statistically significant correlation with SRS-22 scores (r = -0.918, P < 0.01). Final pain, function, mental status, self image and satisfaction domain scores and total SRS-22 score were > or = 4. The time from trauma to operation and the severity of kyphotic deformity were inversely correlated with postoperative correction rates. On the other hand, these 2 parameters were positively correlated with both final PFA and final SRS-22 scores (P < 0.01).

CONCLUSIONS

In light of the present study's findings, we suggest that the technique of anterior decompression, strut grafting, and anterior instrumentation is an effective method for the treatment of post-traumatic kyphotic deformity and that the success of the technique depends on the time from trauma to operation and the severity of baseline deformity, regardless of the type of instrumentation.

Posterior spinal shortening for paraparesis following vertebral collapse due to osteoporosis

STUDY DESIGN

Retrospective case series.

OBJECTIVES

To assess the efficacy of posterior spinal shortening for paraparetic patients following vertebral collapse owing to osteoporosis, especially on instrumentation loosening.

SETTING

Department of orthopaedic surgery, Jichi Medical University Hospital and Omiya Medical Center in Japan.

METHODS

The clinical records and radiographs of 13 patients with paraparesis following vertebral collapse owing to osteoporosis treated with posterior spinal shortening were retrospectively reviewed to evaluate the usefulness of this method. Assessment of the clinical course was done by direct examination in all cases. Ambulatory ability was divided into four categories.

RESULTS

Upon final observation, nine cases were able to walk with a cane or crutch, one case remained in gait training, two cases remained unable to stand and one case with urinary incontinence improved in urinary function. In one case, paralysis deteriorated. Vertebral compression fracture of the end vertebrae that were fixed occurred in three cases complicated with rheumatoid arthritis.

CONCLUSION

The posterior spinal shortening can be a choice for treating delayed paraparesis following vertebral collapse owing to osteoporosis.

Wedge Osteotomy for Treating Post-traumatic Kyphosis at Thoracolumbar and Lumbar Levels

Local post-traumatic kyphosis may impair spinal sagittal balance and result in severe disability. The goal of this study is to evaluate posterior closing wedge osteotomy at the level of injury, by comparing thoracolumbar (T12-L1) and lumbar (L2-4) spinal levels. Thirteen consecutive patients had surgery in an average 13 months after the initial injury. There were 8 thoracolumbar and 5 lumbar deformities. Nine patients already had posterior fixation. Eight patients had preoperative neurological deficits. Sagittal correction was assessed in terms of regional angulation (RA) and effective regional deformity (ERD), which was defined as the difference between the actual RA and the physiological RA for the level. The average follow up was 2.1 years. The average RA passed from 43.8 degrees (31 to 55) to 2.2 degrees (-5 to 7) after surgery. It was 5.3 degrees (-4 to 12), at follow-up. RA and surgical correction were not significantly different between thoracolumbar and lumbar groups. The average ERD was 47.2 degrees (24 to 66) preoperatively and 8.6 degrees (-5 to 37) at follow-up. The ERD passed from 41.8 degrees (24 to 54) to 0.5 degrees (-5 to 6) in the thoracolumbar group, and from 55.8 degrees (50 to 66) to 21.6 degrees (17 to 37) in the lumbar group. The ERD was significantly different initially (P=0.014) and after surgery (P=0.06). The anatomical result was complete in the thoracolumbar group, because the correction of the deformity at this level does not require more than correction of the vertebral body kyphosis. On the contrary, due to adjacent disc damage, the technique did not fully restore the physiological regional lordosis at lower levels.

Biomechanical comparison of anatomic trajectory pedicle screw versus injectable calcium sulfate graft-augmented pedicle screw for salvage in cadaveric thoracic bone

Many salvage options for failed thoracic pedicle screws exist including the use of a different trajectory or the augmentation of the screw with polymethylmethacrylate cement. Although polymethylmethacrylate immediately increases the construct stiffness and the pull-out strength, it may cause bone necrosis, toxin relaxation, and/or neural injury. On the other hand, calcium sulfate bone grafts have a high potential for biologic incorporation and no thermal damage effect. In the current study, polyaxial pedicle screws were first inserted with a straightforward approach on both sides in 17 fresh human cadaveric thoracic vertebrae. The maximal insertion torque for each screw was measured and then the pull-out strengths were recorded. Afterward, these pedicle screws were randomly assigned to be replaced either by graft augmentation or by anatomic trajectory technique for salvage. The graft-augmented screws were placed using the previous holes. The maximum insertional torque for each anatomic trajectory screw was measured. Finally, the pull-out strengths of the revision screws were recorded. The mean maximum insertional torque decreased with the anatomic trajectory salvage technique when compared with the straightforward approach, 0.23 versus 0.38 Nm, respectively (P=0.003). The anatomic trajectory revision resulted in decreased pull-out strength when compared with the pull-out strength of the straightforward technique, 297 versus 469 N, respectively (P=0.003). The calcium sulfate graft augmentation increased the pull-out strength when compared with the pull-out strength of the straightforward technique, 680 versus 477 N, respectively (P=0.017). The mean pull-out strength ratio of revised screw to original was 0.71 for anatomic trajectory and 1.8 for graft-augmented screws, a statistically significant difference (P=0.002).

Pedicle subtraction osteotomy for rigid post-tuberculous kyphosis

We studied 15 patients with healed tuberculosis of the spine and a resultant kyphosis. We selected only those with no neurological deficit and performed a wedge resection of the vertebra using a transpedicular approach. The wedge was removed from the apex of the deformity. For those with a neurological deficit, we chose the conventional anterior debridement and decompression with 360° circumferential fusion. At a mean follow-up of 26.8 months (8 to 46) the outcome was good with an increase in the mean Oswestry Disability Index from 56.26 (48 to 62) pre-operatively to 11.2 (6 to 16) at the latest follow-up.

Combined anterior plus posterior stabilization versus posterior short-segment instrumentation and fusion for mid-lumbar (L2-L4) burst fractures

STUDY DESIGN

Prospective randomized study. OBJECTIVES.: To compare the results of the combined anterior-posterior surgery (Group A) with posterior "short-segment" transpedicular fixation (SSTF) (Group B) in mid-lumbar burst fractures.

SUMMARY OF BACKGROUND DATA

There are no comparative randomized clinical studies on the outcome following operative treatment of mid-lumbar fractures.

METHODS

Forty consecutive patients with L2-L4 fresh single A3-type/AO burst fractures and load sharing score up to 6 were randomly selected to underwent either combined one-stage anterior stabilization with mesh cage and SSTF (Group A) or solely SSTF with intermediate screws in the fractured vertebra (Group B). Kyphotic Gardner angle, anterior and posterior vertebral body height (PVBHr, AVBHr), spinal canal encroachment (SCE), SF-36, VAS, and Frankel classification were used.

RESULTS

The follow-up observation averaged 46 and 48 months for Group A and B, respectively. Operative time, blood loss, and hospital stay were significant more in Group A. More surgical complications were observed in the Group A. After surgery, VAS was reduced to 4.3 and 3.6 for Group A and Group B, respectively. The SF-36 domains Role physical and Bodily pain improved significantly only in Group B (P = 0.05) and (P = 0.06), respectively. Correction of AVBHr, PVBHr, and spinal canal clearance was similar in both groups. Spinal canal clearance did not differ between the two groups, but it was continuous until the last evaluation in Group B. The final Gardner angle loss of correction averaged 2 degrees and 5 degrees for Group A and Group B, respectively. The posttraumatic Gardner deformity did not significantly improve by SSTF at the final evaluation in the spines of Group B. Gardner angle correlated significantly with SCE in Group B and Group A in all three periods and in the last evaluation, respectively. Frankel grade did not correlate with loss of correction of AVBHr and PVBHr in Group A, while it significantly correlated with loss of PVBHr correction and SCE in the patients of Group B. There was no neurologic deterioration after surgery in any patient. VAS and SF-36 scores did not significantly correlate with the loss of kyphotic angle correction and AVBHr, PVBHr at the final observation in any patient of both groups.

CONCLUSIONS

SSTF offered similar significant short-term correction of posttraumatic deformities associated with mid-lumbar A3-burst fractures, but better clinical results as compared to combined surgery. However, SSTF did not significantly maintain the after surgery achieved correction of local posttraumatic kyphosis at the final evaluation. Thus, SSTF is not recommended for operative stabilization of fractures with this severity.

Effects of pilot hole preparation technique on pedicle screw fixation in different regions of the osteoporotic thoracic and lumbar spine

OBJECT

The authors evaluated the effects of pilot hole preparation technique on insertional torque and axial pullout resistance in osteoporotic thoracic and lumbar vertebrae.

METHODS

Using a probe technique and fluoroscopy, 102 pedicle screws were placed in 51 dual-energy x-ray absorptiometry-proven osteoporotic thoracic and lumbar levels. Screws were inserted using the same-size tapping, one-size-under tapping, or no-tapping technique. Insertional torque and axial pullout resistance were measured. Analysis of variance, Fisher exact test, and regression analysis were performed. Same-size tapping decreased pullout resistance in the lumbar spine. There was no effect on pullout resistance in the thoracic spine. Pullout resistance values were lower for all insertion techniques in the upper thoracic spine. Insertional torque and bone mineral density correlated with pullout resistance in the thoracic and lumbar spine.

CONCLUSIONS

Tapping decreased pedicle screw pullout resistance in the osteoporotic human lumbar spine, although it did not affect pullout strength in the thoracic spine. Tapping decreased insertional torque in upper thoracic levels. Surgeons should optimize overall construct rigidity when placing thoracic pedicle screws in patients with spinal segment osteoporosis.

Apical lordosating osteotomy and minimal segment fixation for the treatment of thoracic or thoracolumbar osteoporotic kyphosis

STUDY DESIGN

Retrospective review.

OBJECTIVE

To assess the effectiveness of apical lordosating osteotomy (ALO) and minimal segment fixation through a posterior approach for correcting thoracic or thoracolumbar osteoporotic kyphosis (OK).

SUMMARY OF BACKGROUND DATA

Current surgical options for OK involve a risk of complex surgery in elderly patients, graft problems (e.g., graft dislodgement, subsidence, pseudarthrosis), and instrumentation problems (e.g., adjacent-segment failure, implant pullout). A posterior-only approach was used to make the surgery less invasive and safer.

METHODS

A total of 26 consecutive patients (average age 71.5 years, range 65-81) with thoracic or thoracolumbar OK underwent ALO. Mean follow-up was 3.2 years (range 2.1-6.1). Radiographic studies, complications, and patient satisfaction were assessed.

RESULTS

Mean operating time was 137 minutes, and mean blood loss was 717 mL. In 8 patients with thoracic hyperkyphosis, mean Cobb angle was corrected from 82.7 degrees (range 75 degrees-97 degrees) to 25.8 degrees (range 18 degrees-30 degrees), indicating normal kyphosis. In 18 patients, thoracolumbar kyphosis of 56.3 degrees (range 47 degrees-71 degrees) was corrected to -1.8 degrees (range -11 degrees to 7 degrees). Sagittal imbalance was 12.1 cm before surgery and 4.9 cm afterward. Satisfactory correction was achieved in all patients, without anterior release. Local kyphosis was corrected to -9.1 degrees from 53.6 degrees, and mean vertebral kyphosis to -26.6 degrees from 17.7 degrees. In 17 patients with neurologic deficit, Frankel grades improved after surgery. No major complication occurred. All patients had improved pain, self-image, and overall satisfaction.

CONCLUSIONS

ALO and minimal segments fixation appear to hold promise for the treatment of thoracic or thoracolumbar OK, and may be safer with fewer complications. A larger series with more patients and surgeons is needed for confirmation.

Management of posttraumatic kyphosis: surgical technique to facilitate a combined approach

This report describes a variation of the "posterior-anterior-posterior" surgical techniques to correct posttraumatic kyphosis of the thoracic and lumbar spine with the USS internal fixator. This modification is based on the use of "temporary screws" to mark the entrance of the pedicles in the first stage of the operation (posterior approach, with the patient in prone position). Approaching both columns of the spine simultaneously facilitates correction of the kyphotic defect and permits 360 reconstruction of the spine.

Probing for thoracic pedicle screw tract violation(s): is it valid?

BACKGROUND

Preparation of the thoracic pedicle screw tract is a critical step prior to the placement of screws. The ability to detect pedicle wall violation(s) by probing prior to insertion of thoracic pedicles screws, however, has not been studied. The purpose of this study was to evaluate the inter- and intraobserver agreement and the accuracy in detecting thoracic pedicle screw tract violation(s) among surgeons at various levels of training.

METHODS

With use of a straightforward trajectory, under direct visualization, 108 thoracic pedicle screw tracts (54 cadaveric thoracic vertebrae) were prepared in a standard fashion, followed by tapping with a 4.5-mm cannulated tap. A deliberate pedicle violation was randomly created by an independent investigator in either the anterior, the medial, or the lateral wall in 65 pedicles. Following this, four blinded, independent surgeons at various levels of training probed the specimens on three separate occasions to determine if a breach was present (1,296 discrete data points). Surgeon findings were then recorded as breach present or absent and, if present, breach location. The Cohen kappa correlation coefficient (kappa a) and 95% confidence interval were used to assess the accuracy of the observers and the inter- and intraobserver agreement.

RESULTS

The mean accuracy over three iterations, the validity in detecting the breach location, and the intraobserver agreement varied by level of training and experience, with the most experienced observer (observer 1) scoring the best and the least experienced observer (observer 4) scoring the worst. The three most senior surgeons had good intraobserver agreement. Interobserver agreement was low between the four observers.

CONCLUSIONS

An observer's ability to accurately detect the presence or absence of a pedicle tract violation and the breach location, if present, is dependent on the surgeon's level of training. Probing the pedicle tract prior to placement of pedicle screws in the thoracic spine is likely a learned skill that improves with repetition and experience.

Surgical correction of kyphosis: posterior total wedge resection osteotomy in 32 patients

BACKGROUND

Many surgical procedures have been developed for the treatment of kyphoscoliosis. We present our experience of one technique for posterior total wedge resection osteotomy, with clinical and radiographic results. This is a one-stage solution which results in a shortened posterior column and reduced tension on the spinal cord in rigid angular kyphosis.

PATIENTS AND METHODS

Between 1990 and 2000, we treated 32 patients with rigid local kyphosis by posterior wedge osteotomy and instrumentation. The etiology was congenital malformation in 17 cases, infection in 11 and previous laminectomy in 4 cases. The osteotomy is performed at the apex of the kyphotic deformity and covers two vertebrae. The upper and lower borders of the osteotomy are right inferior to the transverse processes of the upper and lower vertebrae respectively. The apex of the posteriorly based triangular osteotomy is either at the anterior vertebral body or anterior longitudinal ligament.

RESULTS

The mean preoperative angle of local kyphosis was 72 (25-112) degrees mainly at the thoracolumbar region, and it improved to a mean of 23 (0-48) degrees after an average follow-up of 57 (24-108) months. The mean preoperative sagittal plumbline imbalance of 5.5 (2-12) cm was improved to 1.2 (-2-3.5) cm postoperatively. The mean loss of correction since operation was 3.4 (0-11) degrees. Radiographically, solid anterior and posterior fusion was achieved in all patients by 6 months. 1 patient had irreversible paraplegia and 2 others had transient nerve root injury postoperatively.

INTERPRETATION

Posterior total wedge resection osteotomy eliminates the need for anterior procedure and does not cause tractional force on the spinal cord, since the posterior column is shortened. This is an effective one-stage procedure, especially for the treatment of sharp and rigid kyphosis.

Prevention and management of iatrogenic flatback deformity

The most common cause of iatrogenic flatback syndrome is Harrington distraction instrumentation extending into the lower lumbar spine. Other common causes and exacerbating factors include failure to enhance regional lordosis during lumbar fusion for degenerative spondylosis, development of pseudarthrosis or postoperative loss of correction, development of kyphosis at the thoracolumbar junction, development of degeneration and decompensation cephalad or caudad to a prior fusion, and hip flexion contractures. Prevention of flatback syndrome involves preoperative assessment of sagittal balance, avoidance of distraction instrumentation and extension of long fusions into the lower lumbar spine, enhancement of physiologic lordosis during lumbar fusions, and intraoperative positioning with the hips extended. Treatment of flatback syndrome involves corrective pedicle subtraction or Smith-Petersen osteotomies with segmental instrumentation. Polysegmental osteotomies and vertebral column resection may be utilized in cases of sloping global sagittal imbalance and related severe coronal imbalance, respectively. Following surgical treatment, sagittal balance is generally improved with fair-to-good clinical outcomes, high patient satisfaction, and moderately high perioperative complication rates.

Clinical outcome and radiographic results after surgical treatment of post-traumatic thoracolumbar kyphosis following simple type A fractures

The surgical management of post-traumatic thoracolumbar kyphosis remains controversial. The need for combined procedures is subject to debate, especially for post-traumatic kyphosis after simple type A fractures. The aim of this retrospective study was to evaluate radiographic findings, patient satisfaction and clinical outcome after mono-segmental surgical treatment using an anterior procedure alone (group 1, n = 10 patients) and using a one-stage combined anterior and posterior procedure (group 2, n = 15 patients) for post-traumatic thoracolumbar kyphosis after simple type A fractures. The main indication for surgery was pain. There were no statistically significant differences between the patients in the two groups concerning age, cause of injury, time interval between trauma and surgery, preoperative kyphosis and preoperative back pain score. For all these 25 patients, complete follow-up data were available for retrospective evaluation. The median follow-up was 17 years in group 1 and 8 years in group 2. Radiographic documentation and classification was made on the basis of standing antero-posterior and lateral views and computed tomographic scans. Fractures were categorized according to the Magerl classification. Kyphotic deformity was assessed on lateral radiographs using the Cobb method. Kyphosis angles were measured preoperatively, directly postoperatively, and at final follow-up. For clinical evaluation, the back pain scoring system of Greenough and Fraser was used. Patients were requested to score their status prior to trauma, preoperatively and at follow-up. The Wilcoxon test was used for statistical analysis ( P < 0.05 is significant). In all cases radiographic union was achieved. Median kyphosis in group 1 was corrected from 23 degrees preoperatively to 12 degrees postoperatively ( P < 0.01) and was 11 degrees at follow-up. Median kyphosis in group 2 was corrected from 21 degrees pre-operatively to 12 degrees postoperatively ( P < 0.01) and was 12 degrees at follow-up. The median back score in group 1 changed from 66 points before the trauma to 23 points ( P < 0.01) preoperatively and 35 points at follow-up ( P < 0.01). The median back score in group 2 changed from 67 points before the trauma to 20 points ( P < 0.01) preoperatively and 38 points at follow-up ( P < 0.01). In group 2, four patients had complaints due to annoying prominence of the dorsal instrumentation. In all these cases the dorsal instrumentation was removed. Statistical analysis in this series of ten patients with anterior spondylodesis compared with 15 patients with combined one-stage spondylodesis did not reveal objective advantages of the combined procedure as far as the outcome of radiographic correction of kyphosis or patient outcome is concerned. It is therefore concluded that in cases of post-traumatic thoracolumbar kyphosis after simple type A fractures, mono-segmental correction using an anterior procedure alone, with spondylodesis, is the surgical procedure of choice.

Early surgery for thoracolumbar spine injuries decreases complications

BACKGROUND

The proper timing for surgical fracture repair is controversial. Early repair of long bone and cervical fractures reduces complications and is safe. Few studies exist to compare time to surgery with outcomes in thoracolumbar (TL) spine injuries.

METHODS

Patients with TL spine injuries were identified from the trauma registry and divided into two cohorts on the basis of Injury Severity Score (ISS). Cohorts were compared for infectious, respiratory, and total complications in patients who had early (<72 hours from injury) versus late (>72 hours from injury) surgical repair. A retrospective chart review was performed on High ISS patients (> or =15) to identify differences in resuscitation needs and neurologic, respiratory, and infectious complications.

RESULTS

Early surgery, Low ISS patients were younger, received fewer anterior repairs, and had shorter hospitalizations. Early patients in the High ISS cohort had significantly fewer total complications and shorter hospital and intensive care unit lengths of stay. Resuscitative requirements were similar for both surgery groups. More late surgery patients required ventilator support for noninfectious reasons. There was no difference in admission or postoperative neurologic status or the incidence of head injury.

CONCLUSION

Early surgery in severely injured patients with thoracolumbar spine trauma was associated with fewer complications and shorter hospital and intensive care unit lengths of stay, required less ventilator support for noninfectious reasons, and did not increase neurologic deficits.

Inter- and intraobserver reliability of computed tomography in assessment of thoracic pedicle screw placement

STUDY DESIGN

Reliability study of computed tomography imaging in 12 cadaver specimens instrumented with titanium or stainless steel thoracic pedicle screws.

OBJECTIVE

To evaluate inter- and intraobserver reliability of computed tomography scan in determining the accuracy of thoracic pedicle screw placement and to identify the differences in observers' agreement when viewing stainless steel versus titanium screws.

SUMMARY OF BACKGROUND DATA

Computed tomography is often used to assess the accuracy of pedicle screw placement. Accuracy of screw placement is important in the thoracic spine where pedicle morphometry increases the difficulty of screw placement (vital structures are at increased risk). The current literature lacks a critical evaluation of computed tomography reliability among observers.

METHODS

Twelve adult cadavers were instrumented with thoracic pedicle screws. Nine cadavers were instrumented with titanium screws and three with stainless steel screws. The spines were imaged with computed tomography. Three observers used a grading scale to score the extent of pedicle violation and independently scored the placement of each pedicle screw on three separate occasions. Interobserver and intraobserver agreement were determined by using the kappa statistic.

RESULTS

The mean kappa score for interobserver agreement for all 12 specimens (including titanium and stainless steel screws) was 0.51, which correlates with a moderate degree of agreement. Although the interobserver kappa statistics for titanium (kappa = 0.53) and stainless screws (kappa = 0.44) showed a moderate degree of agreement, the intraobserver reliability was substantial (kappa = 0.63). The mean intraobserver kappa for titanium screws was 0.63 and for stainless steel screws was 0.62.

CONCLUSIONS

Our data show that interobserver agreement is moderate and intraobserver agreement is substantial when computed tomography is used to assess placement of thoracic pedicle screws. We conclude that computed tomography is reliable for evaluating thoracic pedicle screw placement throughout the thoracic spine.

Anterior-posterior surgery versus posterior closing wedge osteotomy in posttraumatic kyphosis with neurologic compromised osteoporotic fracture

STUDY DESIGN

Retrospective study.

OBJECTIVES

To compare the surgical results between combined anterior-posterior procedures and posterior closing wedge osteotomy procedures in patients with posttraumatic kyphosis and neurologic compromise secondary to osteoporotic fractures.

SUMMARY OF BACKGROUND DATA

Combined anterior-posterior procedures are usually recommended in cases of kyphotic deformities with neurologic deficit secondary to osteoporosis. However, combined anterior-posterior surgery is associated with significant morbidity in elderly patients.

MATERIALS AND METHODS

Twenty-six patients with posttraumatic kyphosis and neurologic compromise secondary to osteoporotic fracture were indicated for operative intervention using either a combined anterior-posterior surgery (n = 11) or a posterior closing wedge osteotomy procedure (n = 15). The results of the two procedures were analyzed. The average patient age at the operation was 62.6 years (range: 50-82) with a 12:14 male-to-female ratio. Mean follow-up was 3.5 years (range: 2.1-5.4). Preoperative interval from injury to operation was 15.4 months (range: 1-36). There were 20 thoracolumbar (T12-L1) fractures and six lumbar fractures indicated for operative intervention.

RESULTS

In the combined anterior-posterior group, the mean operative time was 351 minutes with a mean blood loss of 2,892 mL. In the posterior closing wedge osteotomy group, the mean operative time was 215 minutes with blood loss of 1,930 mL. Eighteen patients showed a postoperative improvement in Frankel grading, 64% (7/11) in the combined anterior-posterior group, and 73% (11/15) in posterior closing wedge osteotomy group. There were no neurologic or vascular complications in either group. In the combined anterior-posterior group, there were five complications: two postoperative pneumonias, one superficial infection, and two distal screw loosening. There were only two complications in the posterior closing wedge osteotomy group: two distal screw loosening. One of the four cases of distal screw loosening required surgical revision. The other three cases were treated by bracing for more than 6 months.

CONCLUSIONS

Although technically demanding, the posterior closing wedge osteotomy procedure demonstrated a better surgical result with significant less mean operative time and mean blood loss (P < 0.05). It may be a better alternative than a combined anterior-posterior procedure in patients with posttraumatic kyphosis and neurologic compromise secondary to osteoporotic fracture.

Straight-forward versus anatomic trajectory technique of thoracic pedicle screw fixation: a biomechanical analysis

STUDY DESIGN

A biomechanical study on cadaveric thoracic vertebrae using pullout strength, insertional torque, and bone mineral density to determine the optimal sagittal trajectory of thoracic pedicle screws.

OBJECTIVE

To perform a biomechanical study on cadaveric thoracic vertebrae using insertional torque, pullout strength, and bone mineral density to determine the optimal biomechanical sagittal trajectory for placement thoracic pedicle screws. We compared the straight-forward (paralleling the vertebral endplate) with anatomic trajectory (directed along the true anatomic axis of the pedicle).

METHODS

Thirty cadaveric thoracic vertebrae were harvested and evaluated with dual-energy x-ray absorptiometry to assess bone mineral density. Matched, fixed-head pedicle screws were then randomly assigned by side and placed using the straight-forward or anatomic technique under fluoroscopic visualization while recording the maximum insertional torque. Pullout strength testing was then performed.

RESULTS

The maximum insertional torque for the straight-forward technique was 2.58 +/- 0.14 (SE) in pounds, whereas the anatomic technique averaged 1.86 +/- 0.14 (SE) in pounds (P = 0.0005). The maximum insertional torque at the neurocentral junction for the straight-forward technique averaged 1.89 +/- 0.17 (SE) in-lbs. (73% of maximum insertional torque), whereas the anatomic trajectory averaged 1.39 +/- 0.11 (SE) in pounds (75% of maximum insertional torque) (P = 0.007). The average pullout strength using a straight-forward trajectory was 611 +/- 50 (SE) N compared to the anatomic trajectory, which averaged 481 +/- 54 (SE) N (P = 0.034). The pullout strength correlated with mean bone mineral density for both the straight-forward (r = 0.461, P = 0.027) and anatomic (r = 0.598, P = 0.004) techniques.

CONCLUSIONS

The straight-forward technique results in a 39% increase in maximum insertional torque and a 27% increase in pullout strength compared to the anatomic technique. The maximum insertional torque at the neurocentral junction resulted in a 36% increase using the straight-forward technique versus the anatomic trajectory. Bone mineral density directly correlates with pullout strength for both techniques.