Adult spinal deformity correction surgery using age-adjusted alignment thresholds: clinical outcomes and mechanical complication rates. A systematic review of the literature

PURPOSE

Adult spinal deformity (ASD) surgery gives good clinical outcomes but has a high rate of mechanical complications (MC). In 2016, Lafage described the age-adjusted alignment thresholds (AAAT) to adapt the correction in relation to patient's age proposing less aggressive corrections for the elderly population. The aim of this review was to clarify the effectiveness of AAAT to achieve good health-related quality of life (HRQoL) and their relationship with post-operative MC.

MATERIALS AND METHODS

We performed a review of the literature, including articles reporting data on post-operative HRQoL and MC rates in relation to the AAAT. Data were stratified according to whether they matched the AAAT, dividing the population in undercorrected (U), matched (M) and overcorrected (O). The quality of the included studies was assessed using the GRADE and MINORS systems.

RESULTS

Six articles reporting data from 1,825 patients were included. The different categories (U, M and O) had homogeneous pre-operative sagittal parameters (p > 0.05) that became statistically different after surgeries (p < 0.05). Proximal junctional kyphosis (PJK) was more frequent in the O group compared to U (p = 0.05). Post-operative HRQoL parameters were similar in the 3 groups (p > 0.05). The quality of the included studies was generally low with a high bias risk.

CONCLUSION

The results extrapolated from this review are interesting, as for the same HRQoL the U group had a lower MC rate. Unfortunately, the results are inconsistent, mainly because of the low quality of the included studies and the lack of reporting of some important patient- and surgery-related factors.

GAP score potential in predicting post-operative spinal mechanical complications: a systematic review of the literature

PURPOSE

In 2017, the GAP score was proposed as a tool to reduce mechanical complications (MC) in adult spinal deformity (ASD) surgery: the reported MC rate for the GAP proportioned category was only 6%, which is clearly lower to the MC rate reported in the literature. The aim of this study is to analyse if the most recent literature confirms the promising results of the original article.

MATERIALS AND METHODS

Using the PRISMA flow chart, we reviewed the literature to analyse GAP score capacity in predicting MC occurrence. We included articles clearly reporting ASD surgery MC stratified by GAP categories and the score's overall capacity to predict MC using the area under the curve (AUC). The quality of the included studies was evaluated using GRADE and MINORS systems.

RESULTS

Eleven retrospective articles (1,517 patients in total) were included. The MC distribution per GAP category was as follows: GAP-P, 32.8%; GAP-MD, 42.3%; GAP-SD, 55.4%. No statistically significant difference was observed between the different categories using the Kruskal-Wallis test (p = 0.08) and the two-by-two Pearson-Chi square test (P Vs MD, p = 0.300; P Vs SD, p = 0.275; MD Vs SD, p = 0.137). The global AUC was 0.68 ± 0.2 (moderate accuracy). The included studies were of poor quality according to the GRADE system and had a high risk of bias based on the MINORS criteria.

CONCLUSION

The actual literature does not corroborate the excellent results reported by the original GAP score article. Further prospective studies, possibly stratified by type of MC and type of surgery, are necessary to validate this score.

Factors influencing complications after 3-columns spinal osteotomies for fixed sagittal imbalance from multiple etiologies: a multicentric cohort study about 286 cases in 273 patients

PURPOSE

Spinal osteotomies performed to treat fixed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for fixed sagittal imbalance from multiple etiologies.

METHODS

The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicenter cohort of patients who underwent 3-columns (3C) spinal osteotomy, between January 2010 and January 2017. Clinical and radiological data were compared pre- and post-operatively. Complications and their risk factors were analyzed.

RESULTS

Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1 year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were significantly improved (p < 0.001). A total of 164 patients (59.2%) experienced at least 1 complication (277 complications). Complications-free survival rates were only 30% at 5 years. Most of those were mechanical (35.2%), followed by general (17.6%), surgical site infection (17.2%) and neurological (10.9%). Pre-operative neurological status [RR = 2.3 (1.32-4.00)], operative time (+ 19% of risk each additional hour) and combined surgery [RR = 1.76 (1.08-2.04)] were assessed as risk factors for overall complication (p < 0.05). The use of patient-specific rods appeared to be significantly associated with less overall complications [RR = 0.5 (0.29-0.89)] (p = 0.02).

CONCLUSION

Spinal 3C osteotomies were efficient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

Percutaneous Transpedicular Fixation by PEEK Polymer Implants Combined with Cementoplasty for Vertebral Compression Fractures: A Pilot Study

PURPOSE

To evaluate the feasibility and safety of percutaneous transpedicular fixation by PEEK polymer implants and cementoplasty for vertebral compression fracture (VCF).

MATERIALS AND METHODS

From February 2019 to December 2019, 6 consecutive patients (3 men and 3 women; mean age 55 ± 8 years; range 40-64 years) who had percutaneous transpedicular fixation with cementoplasty for the treatment of VCF (5 tumor lesions, 1 traumatic) were included. The procedure duration, length of hospital stay, and complications were reported. Visual analog scale (VAS) and the Oswestry disability index (ODI) for pain and disability were assessed before and 2 months after the procedure.

RESULTS

The mean procedure duration was 74 ± 47 min (range 20-140 min). The median length of hospital stay was 3 days (range 2-63) after the procedure. Only minor adverse events were reported (4 asymptomatic cement leakages) but no severe complications. No cases of procedural site fracture during follow-up were noted (median 198 days; range 78-238 days). The mean VAS score decreased from 6.2 ± 1.8 mm (median 6 mm; range 4-9 mm) before the procedure to 1.7 ± 2.1 mm (median 1; range 0-5 mm) after the procedure. The ODI decreased from 36 ± 14% (range 18-54%) before the procedure to 23 ± 10% (range 11-30%) at 2-months follow-up.

CONCLUSIONS

Percutaneous transpedicular fixation of VCF by PEEK implants with cementoplasty appears feasible and safe.

Revision after spinal stenosis surgery

PURPOSE

To make a literature review on spinal stenosis recurrence after a first surgery and edit rules to avoid this complication.

METHODS

We conducted two separate PUBMED searches to evaluate the revision post-stenosis and degenerative scoliosis surgery using the terms: lumbar vertebrae/surgery, spinal stenosis, spine, scoliosis and reoperation. The resulting papers were categorized into three groups: (1) those that evaluated reoperation post-simple decompression; (2) those that evaluated spinal decompression and fusion for short (3 levels or less) or long (more than 3 levels) segment spinal fusion; and (3) those diagnosing the stenosis during the surgery.

RESULTS

(1) We found 11 relevant papers that only looked at revision spine surgery post-laminectomy for spinal stenosis. (2) We found 20 papers looked at reoperation post-laminectomy and fusion amongst which there were two papers specifically comparing long-segment (> 3 level) and short-segment (3 or less levels) fusions. (3) In the unspecified group, we found only one article. Fifteen articles were excluded as they were not specifically looking at our objective criteria for revision surgery. In regard to revision post-adult deformity surgery, we found 18 relevant articles.

CONCLUSIONS

After this literature review and analysis of post-operative stenosis, it seems important to provide some advice to avoid revision surgeries more or less induced by the surgery. It looks interesting when performing simple decompression without fusion in the lumbar spine to analyse the risk of instability induced by the decompression and facet resection but also by a global balance analysis. Regarding pre-operative stenosis in a previously operated area, different causes may be evocated, like screw or cage malpositionning but also insufficient decompression which is a common cause. Intraoperatively, the use of neuromonitoring and intraoperative CT scan with navigation are useful tool in complex cases to avoid persisting stenosis. Pre-op analysis and planning are key parameters to decrease post-op problems. These slides can be retrieved under Electronic Supplementary Material.

Meta-analysis of the effects of genetic polymorphisms on intervertebral disc degeneration

INTRODUCTION

Chronic low back pain is a significant public health issue. Both its direct and indirect cost represents tens of billions of US dollars. Although chronic low back pain can be the result of many factors, the predominant cause is disc degeneration. Recent studies have shown genetic involvement in up to 74% of cases. This study aimed to evaluate genetic risk factors of disc degeneration by performing a systematic analysis of association studies. The objective is to provide a guide for practice by assessing the clinical relevance of current information.

METHODS AND MATERIALS

We performed a meta-analysis of 3122 items collected from 6 databases. 74 articles were selected according to our inclusion criteria. 18 (24%) could be grouped into 16 meta-analyses of 16 mutations in 12 genes. The statistics of the meta-analysis were conducted through Revman 5.1 software.

RESULTS

The items included are 10,250 cases and 14,136 controls. The GOLD range from 3.42 to 0.38. Two alleles were significantly associated with disc degeneration: IL-6 rs1800797 and MMP-9 rs17576 and one proved to be protective: IL-6 rs1800795. 13 meta-analyses did not yield significant results and methodological heterogeneity.

DISCUSSION

The results highlight the lack of methodological rigor in most of the studies. The absence of international clinical and radiological classification of early disc degeneration, limits the homogeneity of studies. Understanding which populations are predisposed to this significant public health problem may change our approach to diagnostic and therapeutic methods. This work opens up enormous opportunities to provide a genetic solution and consider new diagnostic and therapeutic means to this public health problem.

Maverick total disc arthroplasty performs well at 10 years follow-up: a prospective study with HRQL and balance analysis

PURPOSE

The treatment of low back pain associated to Disc Degenerative Disease (DDD) is still controversial. Segmental Fusion is the gold standard, but many studies have reported that motion-preserving devices bring substantial clinical benefits to patients. Concerns on the associated complications and on the long-term clinical effectiveness of such instrumentations are still present and have led recently to a decrease of the number of Lumbar Total Disk Replacements (TDR). The objective of this prospective study is to present the clinical and radiographic outcomes of the Maverick Lumbar disk prostheses (Medtronic, TE, Memphis, USA) at long-term follow-up.

METHODS

Prospective, single center study of clinical outcome of the treatment with Maverick lumbar Prosthesis of patients with low back pain from DDD resistant to conservative treatment. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Patients were examined preoperatively and at 3 months, 2 and 10 years post-operatively. Visual analog scale (VAS), Oswestry disability index (ODI) and 36-Item Short Form Health Survey questionnaire were assessed to study clinical outcomes. Radiographic studies allowed measurements of range of motion, adjacent segment disease and pelvic and lumbar parameters.

RESULTS

From an initial cohort of 87 patients who underwent TDR between 2003 and 2007 with the Maverick prosthesis, 61 were available at Final follow-up (70%). The clinical outcomes measured by VAS and ODI showed a significant improvement in all the postoperative stages of the follow-up (FU). At 10 years-FU, ODI experienced a mean decrease of 21.1 points, VAS for back pain decreased up to 3.85 and substantial clinical benefit was reached for 55.6% of the patients. Although Mobility of the prosthesis was preserved in 76.8% of the cases, TDR was not clearly protective against ALD.

CONCLUSIONS

A significant, clinically relevant, and lasting reduction of back pain has been achieved in patients who underwent a total disk arthroplasty or a Hybrid construct with Maverik prosthesis. TDR is a safe and effective technique to decrease pain in patients with one or two levels of DDD.

Insufficient restoration of lumbar lordosis and FBI index following pedicle subtraction osteotomy is an indicator of likely mechanical complication

PURPOSE

Pedicle subtraction osteotomies (PSO) enable correction of spinal deformities but remain difficult and are associated with high complication rates. This study aimed to prospectively review different post-operative complications and mechanical problems in patients who underwent PSO as treatment for sagittal imbalance as sequelae of degenerative disc disease or previous spinal fusion.

METHOD

This was a descriptive prospective single center study of 63 patients who underwent sagittal imbalance correction by PSO. Radiographic analysis of pre- and post-operative pelvic and spinal parameters was completed based on EOS images following 3D modeling. Global and sub-group analyses were completed based on the Roussouly classification. A systematic analysis of post-operative complications was conducted during hospital stay and at follow-up visits.

RESULTS

Complications included 15 cases (20.2%) of bilateral leg pain, with transient neurological deficit in 6 cases (9.5%), and 9 cases (12.5%) of early surgical site infections. Intra-operative complications included five tears of the dura mater and two cases of excessive blood loss (>5,000 mL). Two mortalities occurred from major intracerebral bleeds in the early post-operative period. Mechanical complications were principally non-union (9 cases) and junctional kyphosis (3 cases). All 19 post-operative complications (28.1%) were revised at an average of 2 years following surgery. All mechanical complications were found in the patients who had insufficient imbalance correction and this was mainly associated with high PI (>60°) or a moderate PI (45-60º) combined with excess FBI pre-operatively that remained >10° post-operatively.

CONCLUSION

Infection and neurologic complications following PSO are relatively common, and frequently reported in the literature. The principal cause of mechanical complications, such as non-union or junctional kyphosis, was insufficient sagittal correction, characterized by post-operative FBI >10°. The risks of insufficient correction are greater in patients with higher pelvic incidence and those patients who required very high correction.

[Sagittal balance of the spine: a therapeutic revolution]

In humans, the erect position and bipedal walk is possible because of a balance between pelvic and spinal parameters. The most important pelvic parameter is the pelvic incidence which represents the base on which the spine lies. With aging, thoracic kyphosis increases, lumbar lordosis decreases, compromising the spino-pelvic balance. Compensatory phenomenons are possible, but rely mostly on the amplitude of pelvic incidence. Analysis of spino-pelvic parameters and detection of a compensated or uncompensated sagittal imbalance are mandatory before any therapeutic action is undertaken for a degenerative pathology of the spine.

Sagittal balance parameters influence indications for lumbar disc arthroplasty or ALIF

Chronic lower back pain is a potentially incapacitating condition associated with disc degeneration. Although therapy is primarily pharmaceutical, surgery comprising arthrodesis constitutes an alternative. Anterior intersomatic lumbar arthrodesis (ALIF, anterior interbody lumbar fusion) is the reference approach, although total disc arthroplasty may also be undertaken. Analysis of pelvic and spinal parameters provides the best indication of sagittal balance.

MATERIALS AND METHODS

This was a prospective study in a continuous series of 99 patients presenting chronic lower back pain due to disc disease. Pelvic incidence, sacral slope, pelvic tilt, spino-sacral angle (SSA) and the four back types in the Roussouly classification were studied in radiographs of the whole spine under load using an EOS imaging system.

RESULTS

The pre-operative SSA value for the study population was 126.09° ± 8.45° and the mean spine tilt angle was 90° compared with 95° in healthy subjects. Following surgery, the SSA was considerably increased in the discal arthroplasty, resulting in a significantly more balanced spinal position. In the group of patients undergoing arthrodesis using the ALIF technique, no such significant improvement was found despite the use of a lordosis cage. We showed that in cases of low pelvic incidence, it was necessary to maintain a Roussouly type 1 or 2 back without increasing lordosis. The results demonstrated the value of L4-L5 disc prostheses in these subjects. L5-S1 arthrodesis seemed a more suitable approach for treating patients with elevated sacral slope (back type 3 or 4). This new type of analysis of sagittal parameters should be performed prior to all surgical procedures involving lumbar prostheses.

Pelvic parameters: origin and significance

INTRODUCTION

The adoption by humans of an upright position resulted in broadening and verticalisation of the pelvis together with the appearance of characteristic spinal curves, has profoundly modified the structure of the muscles supporting the spine.

MATERIAL

In order to characterise the sagittal balance of the pelvis, it is necessary to define parameters based on notable biomechanical forces involved in the transmission of constraints. The angle of incidence was constructed to enable reproducible analysis of the anatomical characteristics of the pelvis in the sagittal plane. The angle of incidence is the algebraic sum of two complementary angles: pelvic tilt (PT) and sacral slope (SS). Since the value of incidence is fixed for any given patient, the sum of pelvic tilt and sacral slope is a constant value: when one increases, the other necessarily decreases.

RESULT

The position of the lumbar spine, attached to the sacral plateau, is thus affected by the pelvic tilt and by the sacral slope. Consequently, the pelvic parameters affect the entire underlying sagittal spinal profile.

CONCLUSION

Global spinal balance involves harmonisation of lumbar lordosis and thoracic kyphosis taking into account the pelvic parameters.

Sagittal imbalance cascade for simple degenerative spine and consequences: algorithm of decision for appropriate treatment

INTRODUCTION

The main objective of all the sagittal compensating mechanisms is to allow a subject to stand and keep an erect position.

MATERIALS AND METHODS

The cascade of compensating mechanisms appears progressively with the increasing amount of imbalance of the spine until compensation is no longer possible. The loss of lumbar lordosis can be considered as the initiating event of sagittal imbalance. This loss of the normal lordosis pushes the C7 plumb line forward.

RESULTS

The assessment of sagittal balance has to include to be complete: a parameter measuring the global balance of the trunk, either C7 plumb line and sacral plateau, the position of the pelvis rotation by the pelvic tilt, and a description of the position of the lower limbs. Those three parameters have been taken into account by the newly described method called full balance integrated (FBI). This evaluation is easily done on a sagittal full spine standing X-ray from C2 to the pelvis, including the first 10 cm of the femur.

CONCLUSION

Three questions to answer: What is the value of the pelvis incidence? Is the patient balanced? Are there compensatory mechanisms?

Correlation of clinical outcome and spinopelvic sagittal alignment after surgical treatment of low-grade isthmic spondylolisthesis

INTRODUCTION

The aim of this prospective study was to assess the sagittal alignment of the spine and pelvis before and after surgical treatment of isthmic spondylolisthesis with flat sacrum. At the same time, the functional outcome was analyzed and correlation examined.

MATERIALS AND METHODS

This study comprises analysis of 30 subjects (mean age 43 years) with isthmic spondylolisthesis and an average follow-up of 2.5 years after posterior spinal fusion. Radiological spinopelvic parameters were measured and functional evaluation was made using the Oswestry Disability Index.

RESULTS

Significant improvement toward more normal values for PT and SS in relation to PI was observed after surgery. Pelvic incidence was unaffected by surgery. Correction of the spinosacral angle shows that the anterior tilt with anterior sagittal imbalance due to spondylolisthesis may be corrected by reduction and fusion of the slipped level. Functional outcome was satisfactory with a statistically significant difference between preoperative values and final follow-up values. The sub-group of patients with insufficient restoration of sagittal balance parameters had less good outcomes than the others.

DISCUSSION AND CONCLUSION

Surgical management of low- and mid-grade isthmic spondylolisthesis showed good clinical outcome with restoration of correct values for the pelvic position-dependent parameters, i.e., pelvis tilt, sacral slope, C7 plumb line position and SSA.

Equilibrium of the human body and the gravity line: the basics

INTRODUCTION

Bipedalism is a distinguishing feature of the human race and is characterised by a narrow base of support and an ergonomically optimal position thanks to the appearance of lumbar and cervical curves.

MATERIALS

The pelvis, adapted to bipedalism, may be considered as the pelvic vertebra connecting the spine to the lower limbs. Laterally, the body's line of gravity is situated very slightly behind the femoral heads laterally, and frontally it runs through the middle of the sacrum at a point equidistant from the two femoral heads.

RESULTS

Any abnormal change through kyphosis regarding the spinal curves results in compensation, first in the pelvis through rotation and then in the lower limbs via knee flexion. This mechanism maintains the line of gravity within the base of support but is not ergonomic. To analyse sagittal balance, we must thus define the parameters concerned and the relationships between them.

CONCLUSION

These parameters are as follows: for the pelvis: incidence angle, pelvis tilt, sacral slope; for the spine: point of inflexion, apex of lumbar lordosis, lumbar lordosis, spinal tilt at C7; for overall analysis: spino-sacral angle, which is an intrinsic parameter.

Total disc arthroplasty: consequences for sagittal balance and lumbar spine movement

This in vivo biomechanical study was undertaken to analyze the consequences for sagittal balance and lumbar spine movement in three different lumbar disc prostheses. A total of 105 patients underwent total disc replacement in three different centers. The Maverick prosthesis was used in 46 patients, the SB Charité device was used in 49 patients and the Prodisc device was utilized in 10 patients. The analysis was computer assisted, using Spineview and Matlab softwares. The intra and inter-observer reliability and measurement uncertainty was performed. The analysis of lateral X-ray films in flexion-extension allowed to measure the prosthesis positioning, the range of motion (ROM), the localization of the mean center of rotation (MCR), the vertebral translation and the disc height, for each prosthesis device. The sagittal balance was analyzed on a full spine film. The parameters studied were described by Duval-Beaupère. The results were compared to the data found in literature, and compared to 18 asymptomatic volunteers, and 61 asymptomatic subjects, concerning the sagittal balance. The prostheses allowed an improvement of the ROM of less than 2 degrees. The ROM of L5-S1 prostheses ranged from 11.6 to 15.6% of the total lumbar motion during flexion-extension. At L4-L5 level, the ROM decreased when there was an arthrodesis associated at the L5-S1 level. There was no difference of ROM between the three prostheses devices. The MCR was linked to the ROM, but did not depend on the prosthesis offcentering. The disc height improved for any prosthesis, and decreased in flexion or in extension, when the prosthesis was offcentered. An increase of translation indicated a minor increase of the ROM at L4-L5 level after Maverick or SB Charité implantation. The L5-S1 arthrodesis was linked with an increase of the pelvic tilt. The lumbar lordosis curvature increased between L4 and S1, even more when a prosthesis was placed at the L3-L4 level. Total disc arthroplasty is useful in the surgical management of discogenic spinal pathology. The three prostheses studied allowed to retorate the disc height, the ROM, without disrupting the sagittal balance, but induced modification of the lumbar curvature.

Incidence de la situation anatomique de la bifurcation ilio-cave lors de la mise en place d’une prothèse discale

PURPOSE OF THE STUDY

The retroperitoneal mini-invasive anterior approach to the lumbar spine is widely used for disc excision and insertion of a prosthetic disc. A large operating window is needed. Venous wounds constitute one of the most serious complications. We analyzed the angle and position of the iliocaval on the preoperative angio-MRI in search for correlations with the intraoperative findings. Our aim was to determine whether the preoperative angio-MRI gives indications concerning the operative difficulty and the best strategy for prosthesis fitting.

MATERIAL AND METHOD

This prospective study included 35 consecutive patients who underwent surgery for implantation of a Maverick disc prosthesis. Average patient age was 46.7 years. The indication for surgery was isolated degenerative discopathy with invalidating chronic low back pain without alteration of the muscle masse or facet joints. A preoperative angio-MRI was performed with T1 spin-echo sequences for the coronal slices and T2 axial slices passing through the upper extremity of the L5-S1 disc. We searched for correlations between the MRI and operative findings. Elements studied were those used in the Capellades classification: height of the iliocaval junction (high, very high, low, very low), position of the common iliac vein (lateral, intermediate, medial), angle formed by the two common iliac veins.

RESULTS

The lateral position was the most frequent (31.5%). The average junction angle was 65 degrees). The only position where it was not possible to "pass" under the iliocaval junction was for a very low medial localization with a narrow angle (45 degrees).

DISCUSSION

Our series included a homogenous group comparable with other series in the literature. The junction angle for very low medial localizations is of considerable importance because it is impossible to fit the implant in the L5-S1 under the iliocaval junction if the angle is over 60 degrees.

CONCLUSION

The position of the iliocaval junction, and particularly its angle, are of considerable importance for insertion of an L5-S1 disc prosthesis. The preoperative angio-MRI provides information on the potential difficulty of the insertion. In addition, with this preoperative information, the patient can be warned that it may not be possible to insert the implant so that a therapeutic alternative may be proposed.

[Video-assisted mini-thoracotomy for surgical treatment of thoracolumbar junction fractures]

PURPOSE OF THE STUDY

There are several solutions for the treatment of fractures of the thoracolumbar junction (classical anterior, posterior, combined approaches). The advent of video-assisted minimally invasive techniques has helped minimize complications. The aim of this work was to analyze the clinical and radiological outcome in a prospective series of 20 patients who underwent video-assisted mini-thoracotomy for the treatment of thoracolumbar junction fractures.

MATERIAL AND METHODS

This prospective study included 20 patients, mean age 43.3 years, with at least one year follow-up. All patients presented a normal neurological examination (Frankel E). Fractures were classified Magerl A (n = 19) and B (n = 1). Corporectomy/correction (aided with an endodistractor in the last nine cases) was performed with grafting and osteosynthesis. Perioperative and postoperative complications were noted. Focal kyphosis and regional angulation were noted before and after the operation and at last follow-up using the Stagnara system.

RESULTS

The arthrodesis had fused at last follow-up in all patients. There were three cases of alelectasia which regressed in two months. Overall outcome showed satisfactory angular correction which was maintained at last follow-up. The gain in focal kyphosis was 13.71 degrees on average in the immediate postoperative period and persisted at last follow-up (13.31degrees). The gain in corrected regional angulation was 14 degrees in the immediate postoperative period and 14 degrees at last follow-up. The gain in focal kyphosis and regional angulation was two-fold greater with the endodistractor than with external maneuvers.

DISCUSSION

The complication rate was very low. Corrections obtained were comparable with those reported in the literature and persisted over time.

CONCLUSION

Bearing in mind the learning curve, there are fewer complications with the video-assisted minimally invasive approach than with classical thoracotomy or anterior surgery. This is true for perioperative and early and late postoperative complications. The correction achieved is satisfactory and lasting. A specific ancillary is essential for the reduction and for fitting the anterior graft without lost of correction. This technique combines the best results achieved with thoracotomy (Onimus) with a limited rate of complications.

Clinical results of Maverick lumbar total disc replacement: two-year prospective follow-up

Disc prosthesis is the new treatment for degenerative disc disease in the lumbar spine. Key to assessing the interest in this new motion technique is evaluating the results in terms of functional and radiologic outcomes. This prospective study reports the outcome of 64 Maverick devices implanted between January 2002 and November 2003. The degree of improvement was equivalent to that obtained with anterior fusion cages using the mini-invasive technique. Radiographic follow-up in this series showed a degree of mobility close to normal. The technique is safe because the intra- and postoperative complication rate is low. The Oswestry score improved for 75% of patients. This improvement is significantly correlated with facet arthrosis and muscle fatty degeneration.

Postoperative deep wound infections in adults after spinal fusion: management with vacuum-assisted wound closure

OBJECTIVE

Vacuum-assisted wound closure (VAC) exposes the wound bed to negative pressure, resulting in removal of edema fluid, improvement of blood supply, and stimulation of cellular proliferation of reparative granulation tissue. It has been used to treat open wounds in the extremities, open sternal wounds, pressure ulcers, and abdominal wall wounds. This study retrospectively reviewed instrumented spine fusions complicated by surgical wound infection and managed by a protocol including the use of VAC in order to evaluate the efficacy of applying vacuum therapy on patients with deep spine infections and exposed instrumentation.

METHODS

Twenty consecutive patients with deep wound infections after undergoing spinal fusion procedures were studied. There were 12 men and 8 women with an average age of 55 years (31-81 years). Eight patients had undergone concomitant anterior and posterior arthrodesis, nine patients had a posterior spinal fusion, and three patients had a transforaminal lumbar interbody fusion. Seven patients had a decompression with exposed dura. Sixteen patients presented with a draining wound within the first 6 weeks postoperatively (average 24 days). There were four patients who presented with back pain and temperature after 1 year postoperatively (average 3 years). All patients were taken to the operating room for irrigation and debridement followed by placement of the VAC with subsequent delayed closure of the wound.

RESULTS

There was an average of 1.8 (1-8) irrigation and debridement procedures prior to placement of the VAC. Once the VAC was initiated, there was an average of 2.2 (2-3) procedures until and including closure of the wound. The wound was closed an average of 7 days (5-14 days) after the placement of the initial VAC in the wound. All patients tolerated the VAC without adverse effects. All patients were kept on a 6-week course of intravenous antibiotic therapy. The average follow-up was 10 months (6-24 months). There were no cases of uncontrolled sepsis once the VAC was initiated. All patients achieved a clean closed wound without removal of instrumentation at a minimum follow-up of 6 months.

CONCLUSION

VAC therapy is an effective adjunct in closing complex deep spinal wounds with exposed instrumentation.

Dislocations with intervertebral disc prosthesis: two case reports

To date, only three cases of artificial disc prosthesis dislocation have been reported in the literature. We present in detail two additional cases of prosthesis dislocation and discuss the surgical interventions undertaken that resulted in a good clinical outcome in both patients.

Vertebroplasty for osteoporotic spine fracture: prevention and treatment

There is a relatively high prevalence of osteoporotic vertebral compression fractures (VCFs) in the elderly population, especially in women aged 50 or older. The result of these VCFs is increased morbidity and mortality in the short and long term. Medical treatment of these fractures includes bed rest, orthotics, analgesic medication and time. Percutaneous vertebroplasty (PVP) consists of percutaneous injection of biomaterial, such as methylmethacrylate, into the VCF to produce stability and pain relief. Biomechanical testing has shown that PVP can restore strength and stiffness of the vertebral body to the pre-fracture levels. Clinical results show immediate and maintained pain relief in 70-95% of the patients. Possible major complications include cement leakage into the spinal canal or into the venous system. Additionally, percutaneous vertebroplasty may alter the normal loading behavior of the adjacent vertebral body, and there is an increased risk of adjacent segment VCF. Kyphoplasty is a new technique, which introduces a balloon into the vertebral body transpedicularly to reduce the VCF while creating a cavity for the cement injection. This technique has the benefit of kyphosis reduction as well as less cement leakage. Research continues into the development of injectable biomaterials that are resorbable and allow for new bone formation. Vertebroplasty and kyphoplasty are safe and effective in the treatment of osteoporotic VCFs. They may allow for a faster return to function, and thus avoid the morbidity associated with medical treatment.

Lumbar lateral interbody cage with plate augmentation: in vitro biomechanical analysis

Many studies have concluded that stand alone cages provide limited stabilization to the spine, and this primary stabilization decreases postoperatively due to various factors. A supplemental fixation may, therefore, be needed to improve the stability. Extensive biomechanical analysis was performed in the present study to further evaluate the stabilization achieved by a laterally inserted cage and the role of an anterior lateral supplemental fixation. Eight human cadaver functional spinal units were subjected sequentially to four different test conditions: (1) intact, (2) instrumented laterally with a long cylindrical threaded cage, (3) the same cage supplemented with a lateral fixation plate, the plate being firmly connected to the cage, and (4) removal of the connection between the plate and the cage. Pure moments were applied to each specimen in a quasi static manner, ranging from -7 Nm to 7 Nm in flexion/extension, lateral bending and axial rotation. Three-dimensional segmental motions were simultaneously recorded under each loading condition. Statistical analysis was carried out on the motion parameters, including the range of motion (ROM) and the neutral zone (NZ). Inter-group comparisons were made using the Friedman test and the Wilcoxon test. The results showed that the stand alone lateral cage provided stabilization by increasing segmental stiffness above that of the intact spine. The stiffness increase ratios were: 1.6 in flexion/extension ( P=0.07), 1.3 in lateral bending ( P=0.4) and 1.0 in axial rotation ( P=0.67). A supplemental plate provided significant reinforcement of the stabilization. The stiffness increase ratios relative to the intact spine were: 3.1 in flexion/extension ( P=0.012), 5.0 in lateral bending ( P=0.012) and 2.3 in axial rotation ( P=0.012). After removal of the connection between the cage and the plate, the stiffness ratios were: 2.7 in flexion/extension ( P=0.027), 4.6 in lateral bending ( P=0.027) and 2.1 in axial rotation ( P=0.027). Globally, the cage alone increased the segmental stiffness above that of the intact spine by a factor of 1.1 ( P=0.39), with the supplemental plate, segmental stiffness increased by a factor of 3.1 ( P<0.01), and the unconnected cage/plate increased stiffness by a factor of 3.0 ( P=0.02). Supplementation of the lateral cage with an anterolateral plate was thus shown to provide significant additional stabilization in all directions, which may potentially compensate for the postoperative decrease in segmental stability.

Minimally invasive endoscopic approach to the cervicothoracic junction for vertebral metastases: report of two cases

The anterior cervicothoracic junction is difficult to expose and many techniques have previously been described. Most of them require an extensile exposure, which can lead to significant morbidity. The aim of this study is to present a less invasive approach, allowing the same exposure on the spine as a larger one. The approach begins with the same incision as the Smith-Robinson technique: a blunt dissection of the posterior face of the manubrium is performed with the finger. An endoscope is inserted through 10-mm trocars, one above the manubrium and the second through the second rib space. The upper mediastinal space is exposed; the dissection is performed on the left side, between the esophagus and trachea medially, between the innominate vein and brachio-cephalic artery distally, and between the left common carotid and internal jugular vein laterally. The recurrent nerve must be protected. Two patients with spine metastases underwent this new approach. A strut graft was fixed anteriorly after decompression of the spinal cord. Levels T1-T3 can be well exposed through this approach, allowing complete vertebral body removal at level T1 or T2. After body removal, the posterior longitudinal ligament is well exposed, allowing complete release of the spinal cord. The use of the endoscope is the key to providing a good view of the spine without an extensile exposure. This new approach is technically feasible. The exposure is sufficient for vertebral body resection and reconstruction by strut graft. The procedure is less aggressive and painful than sternotomy.

[Interbody arthrodesis of the lumbar vertebrae using retroperitoneal videoendoscopy. A preliminary study of 38 cases]

AIM OF THE STUDY

To report a series of 38 patients presenting retroperitoneoscopic inter-body fusion of the lumbar spine from L2 to L5, performed between 1995 and 1998.

PATIENTS AND METHODS

This series included 25 women and 13 men aged from 16 to 74 years (mean age: 48.5 years). Surgery was performed in 32 patients for primary degenerative or post-operative instability of the lumbar spine, in five patients for painful sequels of burst fracture, and in one patient for sequels of disc infection. The main complaint was lumbar pain but a real sciatic pain was present in nine patients and was not a contraindication for this surgery. Standard X-rays were performed for each patient, and MRI performed in 30 patients confirmed the diagnosis and was also useful in determining vascular abnormalities. A cast immobilisation of the lumbar spine was done as a preoperative test in every patient.

RESULTS

Forty-two levels were fused: 31 with a cage filled with cancellus bone and screwed between the end plates, and 11 with cancellus bone alone or in association with bone substitute, such as beta TCP. Post-operative complications included only a transient paresthesia of the thigh in two cases and a chyloretroperitoneum spontaneously resolutive. After 2.3 months of plaster immobilisation with a follow-up of 11.4 months, patient satisfaction rate was 84.5%, with 68.5% reporting no further back pain. The improvement was estimated by Prolo score. Fusion was considered effective by X-ray examination in all patients with an increase in the intervertebral space of 35% and a recovery of the local lordosis of 15%.

CONCLUSION

Retroperitoneoscopic surgery is an elegant and secure method for lumbar interbody fusion of L2 to L5 with very few postoperative complications.

Evolution of the local calcium content around irradiated beta-tricalcium phosphate ceramic implants: in vivo study in the rabbit

To evaluate whether dissolved calcium from tricalcium phosphate implants contributes to osseous wound healing in bone defects, the authors used nuclear radioactivated materials. Six months after irradiation, the calcium was still radioactive. Samples of the material were prepared and placed in rabbit condyles for 1, 3 and 9 months. Over time the condyles were retrieved and treated for histology or radiocounting. Measurements of the radioactivity of the slices and histomorphometry of the implants and surrounding tissues were performed. The authors observed that the radioactivity decreased regularly. Connective tissue had penetrated the pores and totally invaded the implants, first at the periphery of the implants, then inside the pores. Comparison of the results of radioactivity and histomorphometry suggest that part of the calcium from the implants was re-used specifically in the new osseous tissue.

Tri-calcium phosphate ceramics and allografts as bone substitutes for spinal fusion in idiopathic scoliosis as bone substitutes for spinal fusion in idiopathic scoliosis: comparative clinical results at four years

The authors present the results of a comparative study of two series of posterolateral arthrodeses for scoliosis performed using COTREL DUBOUSSET instrumentation. Fifty-four consecutive patients underwent surgery for idiopathic scoliosis using the same technique. Thirty received a graft consisting of a mixture of corticocancellous autologous and allogenic bone frozen at -80 degrees, and 24 patients were grafted with a mixture of cortico-cancellous autologous bone and sticks of tricalcium phosphate (TCP, Biosorb, SBM, Lourdes, France). All patients were seen at three, six and twelve months, then once a year for at least four years with clinical and radiological evaluation at each visit. At the final follow up visit, no radiologic signs of pseudoarthrosis were found in either group with a minimum follow-up of 4 years. The appearance of bone callus was considered satisfactory at 6 months in all cases; moreover callus seemed to be more important in the TCP series, although this assessment was subjective. TCP resorption was total after 2 years, while allograft fragments were visible on x-rays after 2 years. Minor mechanical complications occurred but did not influence the results. Loss of correction was 8% of that initially obtained in the allograft group and 2% in the TCP group. Loss of correction did not progress after 6 months in the TCP group and after 2 years in the allograft group. Based upon this experience, the use of synthetic bone substitutes such as TCP would appear to be a valuable alternative to allografts in posterolateral spinal arthrodesis for idiopathic scoliosis, and it would eliminate the risk of viral contamination inherent to allograft implantation. To our knowledge, there have been no previous comparative studies concerning the use of tricalcium phosphate versus allograft in the literature.

Distal rupture of the tendon of biceps brachii. Evaluation by MRI and the results of repair

We report ten cases of rupture of the distal part of the tendon of biceps brachii in patients aged from 27 to 58 years. MRI allowed assessment of the degree of retraction of the tendon which was related to the integrity of the bicipital expansion. When the retraction exceeded 8 cm the expansion was always ruptured. When there was doubt, or in longstanding injury, MRI allowed the lesions to be defined. Surgical repair was by reinsertion on the radial tuberosity at one or two fixation points in eight patients and reinsertion on the anterior brachial muscle in one. The other patient refused surgery. The MRI findings were confirmed at operation. Use of fixation points allowed minimal intervention, thereby reducing the risk of damaging the radial nerve. One year after operation, dynamometric evaluation of the strength of flexion and supination confirmed that the best results were obtained by reinsertion to the radial tuberosity.

DISTAL RUPTURE OF THE TENDON OF BICEPS BRACHII

We report ten cases of rupture of the distal part of the tendon of biceps brachii in patients aged from 27 to 58 years. MRI allowed assessment of the degree of retraction of the tendon which was related to the integrity of the bicipital expansion. When the retraction exceeded 8 cm the expansion was always ruptured. When there was doubt, or in longstanding injury, MRI allowed the lesions to be defined.

Surgical repair was by reinsertion on the radial tuberosity at one or two fixation points in eight patients and reinsertion on the anterior brachial muscle in one. The other patient refused surgery. The MRI findings were confirmed at operation. Use of fixation points allowed minimal intervention, thereby reducing the risk of damaging the radial nerve. One year after operation, dynamometric evaluation of the strength of flexion and supination confirmed that the best results were obtained by reinsertion to the radial tuberosity.

[Acromio-clavicular joint cyst. Surgical treatment]

A chronic cyst of the acromioclavicular joint was treated in 3 patients who were followed up for an average period of 26 months. All three were over 60 years old and presented with a massive rupture of the rotator cuff with a subnormal range of passive motion; active motion was variably affected and was painful. The patients underwent resection of one cm of the lateral end of the clavicle, together with resection of the cyst and synovectomy of the upper part of the pathologic humero-acromial joint; the coraco-acromial ligament was left in place. With a mean follow-up of 26 months, the 3 patients have significant pain relief and no cyst has recurred. The authors propose a mechanism to explain the persistence of the cysts in patients with massive rotator cuff tear: elevation of the arm brings the humeral head upwards and forces synovial fluid into the acromioclavicular joint through a perforation in the frayed capsule; this communication is later obstructed by synovial fringes which prevent drainage of the fluid. Excision of the synovium cures the problem.

Traumatic tear of the rotator interval

We studied 10 patients with capsular tear of the glenohumeral joint in the rotator interval -- the triangular space separating the supraspinatus and subscapular tendons. The patients, manual laborers and athletic people, had no previous shoulder pain. Tears appeared after forced internal rotation caused by trauma. The pain was anterior and radiated distally. Pain was absent at rest but recurred immediately after activity was resumed. On examination, range of motion was normal. Hawkins' impingement sign and the palm-up test usually caused pain. Radiographic findings were normal. Arthrography showed leakage of contrast medium into the subscapularis fossa. The tear was not visualized with ultrasonography or magnetic resonance imaging. Eight patients underwent an operation consisting of minimal acromioplasty with coracoacromial ligament resection, coracoidplasty, and suture of the rotator interval. All patients had relief of pain and return of full function.

A study of the fasciocutaneous vascularisation of the arm. Surgical applications

The data on the fasciocutaneous vascularisation of the medial aspect of the arm are incomplete in the literature. This study presents the methodology and results of an anatomic study on 19 upper limbs with arterial injection. The vascularisation of the upper part of this region is provided in 68% of cases by the superficial fasciocutaneous branch (SFCB) of the superior ulnar collateral artery (SUC), that of the middle and lower part by 3-4 fasciocutaneous pedicles originating from the SUC which are prolonged distally by the recurrent posterior ulnar artery. The SFCB has important relations with the ulnar nerve; it travels dorsal to the nerve in 64% of cases and then allows the raising of a distally-pedicled ulnar flap with a 3:1 ratio. In other anatomic configurations, a flap with retrograde flow supplied by the inferior pedicles of the SUC can always be raised. Its ratio is then 2:1. this flap allows coverage of all cases of posterior or anterior losses of substance at the elbow. These results supplement the data required for the raising of a distally-pedicled medial brachial flap, but also of a proximally-pedicled superior medial brachial flap and of a free superior medial brachial flap transposed by microsurgical means.

Epicondylitis after treatment with fluoroquinolone antibiotics

We report two cases of epicondylitis of the elbow occurring after treatment with fluoroquinolone antibiotics. Both patients had intense pain which appeared very shortly after the first dose of the drug and was not relieved by conservative treatment. Ultrasonography revealed extensive inflammatory lesions with pseudonecrotic areas. MRI confirmed the lesions and also showed a subclinical abnormality of the adjoining tendons. The persistent nature of the pain was the indication for surgical release of the extensor mechanism. After operation pain disappeared completely and the patients were able to return to their normal activities. Lesions of the tendo Achillis are a well-known side-effect of treatment with fluoroquinolone. Our two cases show that such lesions may occur elsewhere. They also indicate the need for caution when prescribing these antibiotics to patients at risk of tendon lesions, such as top-level sportsmen or patients on dialysis or steroid treatment.

Influence of porosity on the mechanical resistance of hydroxyapatite ceramics under compressive stress

Calcium phosphate ceramics are biocompatible and may develop interactions with human living bone tissues. They are used clinically on the surface of orthopaedic implants to improve primary fixation or in the form of porous blocks. Their brittleness is often advanced as a limitation of their common clinical use. In order to study the influence of porosity on the mechanical strength of calcium phosphate ceramics, we have tested 150 cylindrical hydroxyapatite samples with open porosity. The total porous volume of the ceramics has been varied from 20% to 60% and the pore size from 5 microns to 400 microns. The result indicates that not only total porosity but also pore size can influence compressive strength, which is in good agreement with theoretical work. After mathematical treatment of the results, the experiments have been modelled in the form of a polynomial equation which can be used to predict and optimize mechanical strength. Moreover, this work supports the fact that compressive strength of controlled open porosity implants can be comparable with that of cancellous or cortical human bone, and suggests that porosity should be fitted to clinical application.

[Epicondylitis induced by fluoroquinolones in athletes. Apropos of 2 cases]

Epicondylitis occurred in two leisure athletes who were taking fluoroquinolones. No similar cases have been reported in the literature. In both cases, pain occurred early after initiating drug therapy. Pain was intense and was not controlled by usual care. Echography demonstrated major inflammatory lesions with pseudo-necrosis. Magnetic resonance imaging confirmed the lesions and gave evidence of infraclinical lesions of the adjacent tendons. Surgical disinsertion of the epicondyles with biopsy was indicated due to the persistent pain. Histological examination revealed unspecific lesions of hyalin degeneration and a few giant cells in one case. Pain disappeared after surgery and the patients were able to return to their work, but neither was able to continue his sports activity. Lesions of the Achilles tendon have been observed in patients taking fluoroquinolone and the two cases reported here confirm the possibility of other localizations. Care must therefore be taken when prescribing these antibiotics in patients at risk (dialysis patients, those on corticosteroids, high-performance athletes).

[Tissue and systemic diffusion of idrocilamide after cutaneous administration]

Experimental findings have demonstrated that idrocilamide exhibits antiinflammatory and muscle relaxant properties due at least in part to tissular effects. Percutaneous diffusion of a 10% glycero-alcoholic idrocilamide solution was studied in ten patients scheduled to undergo total knee replacement. Four 200-mg doses of idrocilamide were applied to the suprapatellar area at 12-hour intervals before surgery. Pain was evaluated using a visual analog scale before and after treatment. Surgery was performed 1.75 to 3.5 hours after the last idrocilamide dose. Idrocilamide was assayed using high performance liquid chromatography in tissue, plasma, and joint fluid specimens taken during the surgical procedure. Topical administration of idrocilamide on healthy skin produced significant concentrations of the drug in all the tissue specimens, including subcutaneous fat, muscle, tendon, synovium, and knee capsule. Tissue levels were consistently higher than synovial fluid and plasma levels, indicating that little systemic diffusion occurred. Idrocilamide levels in potential target tissues might influence clinical effects.

A new radiologic measurement for the diagnosis of Haglund's deformity

The authors describe a new method of radiologic measurement of "Haglund's deformity", based on a radiologic study of 31 feet operated for posterior heel pain and more especially for calcaneal tendinopathies related to deformity of the calcaneus, and on a series of 60 asymptomatic feet. This angular approach requires a lateral weight-bearing view and proved positive in 85% of symptomatic feet, with only 14% of false-positives in the control group. It thus proves markedly superior to previously described radiologic formulations, since it allows not only for the size and site of the deformity of the posterosuperior part of the calcaneus but also for the angle of verticalization of the latter.

Anatomic basis of the sural fascio-cutaneous flap: surgical applications

Studies of the fascio-cutaneous vascularization and innervation of the leg seem incomplete. After reviewing the classical findings, the authors report on their anatomic study 15 dissections. Perforating pedicles, originating from the peroneal artery (3 to 5) and posterior tibial artery (4 to 5) destined for the skin and fascia of the posterior aspect of the leg were constantly found. This study suggests the possibility of a distally based sural fascio-cutaneous flap, a flap which has been successfully constructed clinically.

[Anatomic and histologic study of the valves of the internal jugular veins]

In 200 dissections of internal jugular veins, the valves were investigated with regard to their constitution, their macroscopic and their microscopic anatomy. In 88% of the cases, an ostial valve was found. The cusp of each consists of two parts in 77%, of only one part in 16%, and in 7% of three parts. In 12% these valves are not found. The structure, the configuration, the topography of these valves are explained. The stroma of the valve consists of collagen and elastic fibrils. The surface of the luminal and parietal part is covered by endothelial cells with elastic and muscular fibers close to the attachment of the cusp to the vein wall.

[The distally based sural fascio-cutaneous flap. A new technic for the coverage of loss of substance of the lower leg]

Prognosis of compound open fractures has been transformed by the use of plastic surgery to cover wounds. However, loss of substance of lower third of leg remains a delicate problem frequently requiring the use of microsurgical techniques by experienced teams. The sural cutaneo-aponeurotic distal base flap, the subject of a detailed anatomical study by the authors, can resolve the problem without affecting muscle capital and at the price of minor esthetic sequelae. Results in two clinical cases confirm reliability of this flap.

The supra-transverse intermetatarsocapital bursa: a description and its relation to painful syndromes of the forefoot

Very many painful syndromes of the forefoot remain without a satisfactory explanation; although this region contains quite specific structures, it has suffered from the application of analogies with disorders of the hand. Among these specific components, the presence of the supra-transverse intermetatarsocapital bursa provides an explanation of such clinical entities as the acute syndrome of the second intermetatarsal space and gives fresh impetus to the debate on the etiopathogenesis of Morton's metatarsalgia. On the basis of 25 dissections, the authors studied the region between the metatarsal heads, confirming the presence of these bursae and specifying their site and size and particularly their relations with the common plantar digital nerve at its bifurcation into collateral nerves.

[Study of the sub-transversal intercapitometatarsal serous bursae]

About twenty five dissections of the forefoot, we have precised the presence of serosis burses, upper the profound transversal intermetatarsus ligament, in the intercapito metatarsus region. These burses, recently described by Bossley (New Zealand), are not described in the classical anatomic books. Variable in the first and forth spaces, they are always present in the second and third spaces, where their very anterior situation realizes a privileged connexion with the digital nerve, at its division. In precising the situation and the anatomic characteristics of these burses, this study contributes to clarify the etiology of some inflammatory or static pains of the foot.