Subtotal vertebrectomy and spinal fusion for cervical spondylotic myelopathy

A Comparison of Clinical and Functional Outcomes Following Anterior, Posterior, and Combined Approaches for the Management of Cervical Spondylotic Myelopathy

BACKGROUND

The key determinants when planning surgery in patients with CSM are the direction of compression, number of levels, sagittal alignment and instability. However there is no literature that compares the clinical and functional outcomes following different approaches in patients selected for surgery.

AIMS

Prospective non-randomized study that aims to compare the clinical and functional outcomes following surgical approaches with the goal of planning the optimal surgical strategy.

MATERIAL AND METHODS

75 patients- 61 males and 14 females (mean age: 64.2 years) with CSM underwent spinal decompression using an anterior (30), posterior (35) or combined approach (10).The surgical approach was selected based on the above mentioned key determinants. Functional disability was measured using the modified Japanese Orthopaedic Association score for myelopathy. Based on this the recovery rate was calculated. The mean followup duration was 21 months (range 6-72 months).

RESULTS

The preoperative mJOA score was 11.01 and the functional disability was graded as mild in 15, moderate in 50 and severe in 10. Postoperatively, the mJOA score improved to 16.41.The overall recovery rate was 77.25%.Patients with mild deficits/disability preoperatively had a significantly better recovery (<0.01) than those with more severe disability. There was comparable improvement in the functional status within the groups with the recovery rates were 83.37%, 76.6% and 64.13%.The blood loss, operative time and peri-operative complication rate were significantly higher with a combined surgery (33%) as compared to anterior (13.3%) or posterior approaches 14.8%.

CONCLUSIONS

Outcomes are excellent following surgery for CSM.The best recovery is seen in patients with mild to moderate functional disability at the time of surgery.

Biomechanics of Hybrid Anterior Cervical Fusion and Artificial Disc Replacement in 3-Level Constructs: An In Vitro Investigation

Background

The ideal surgical approach for cervical disk disease remains controversial, especially for multilevel cervical disease. The purpose of this study was to investigate the biomechanics of the cervical spine after 3-level hybrid surgery compared with 3-level anterior cervical discectomy and fusion (ACDF).

Material/Methods

Eighteen human cadaveric spines (C2-T1) were evaluated under displacement-input protocol. After intact testing, a simulated hybrid construct or fusion construct was created between C3 to C6 and tested in the following 3 conditions: 3-level disc plate disc (3DPD), 3-level plate disc plate (3PDP), and 3-level plate (3P).

Results

Compared to intact, almost 65~80% of motion was successfully restricted at C3-C6 fusion levels (p<0.05). 3DPD construct resulted in slight increase at the 3 instrumented levels (p>0.05). 3PDP construct resulted in significant decrease of ROM at C3-C6 levels less than 3P (p<0.05). Both 3DPD and 3PDP caused significant reduction of ROM at the arthrodesis level and produced motion increase at the arthroplasty level. For adjacent levels, 3P resulted in markedly increased contribution of both upper and lower adjacent levels (p<0.05). Significant motion increases lower than 3P were only noted at partly adjacent levels in some conditions for 3DPD and 3PDP (p<0.05).

Conclusions

ACDF eliminated motion within the construct and greatly increased adjacent motion. Artificial cervical disc replacement normalized motion of its segment and adjacent segments. While hybrid conditions failed to restore normal motion within the construct, they significantly normalized motion in adjacent segments compared with the 3-level ACDF condition. The artificial disc in 3-level constructs has biomechanical advantages compared to fusion in normalizing motion.

Cervical Myelopathy Secondary to Ossification of the Posterior Longitudinal Ligament in a Caucasian Patient

Cervical myelopathy consequent on ossification of posterior longitudinal ligament (OPLL) is very rare in Caucasians. A 65-year-old Anglo-Saxon woman developed progressive gait disturbance, paresthesia in both legs and urinary urge incontinence. Radiological examination showed OPLL from fifth to seventh cervical vertebral level; the dense OPLL was graphically displayed by three-dimensional computerized tomography. Medial corpectomy, C5 to C7, and removal of OPLL, with subsequent fusion C4 to Tl using a free fibula graft resulted in clinical improvement. Three dimensional computerized tomographic imaging is a valuable diagnostic procedure in OPLL.

Changes in the range of motion of the cervical spine and adjacent segments at ≥24 months after uninstrumented corpectomy for cervical spondylotic myelopathy

BACKGROUND

Few clinical studies have described the changes in the range of motion (ROM) of the cervical spine and adjacent segments following central corpectomy. We aimed to quantify the changes in range of motion (ROM) of the cervical spine and the adjacent segments at ≥24 months following uninstrumented central corpectomy (CC) for cervical spondylotic myelopathy (CSM) and to determine the contribution of the adjacent segments to the compensation for loss of motion of the cervical spine following CC.

METHODS

Preoperative and follow-up lateral cervical spine radiographs of 36 patients who underwent CC for CSM between 2001 and 2007 were compared for the ROM of the subaxial cervical spine, superior and inferior adjacent segment. Anterior osteophytes as seen on the radiographs were classified according to Nathan's grading system.

RESULTS

The mean duration of follow-up was 48.5 months. At follow-up, the total cervical spine ROM decreased by 18.3° ± 2.2° (p < 0.001), the superior adjacent segment ROM increased by 2.3° ± 0.9° (p = 0.01) and the inferior adjacent segment ROM, measured in 20 cases, increased by 6.2° ± 1.7° (p = 0.01). The superior adjacent segment showed a 70% increase, whereas the inferior adjacent segment showed a 110% increase in mobility. Nathan's grade at the superior or inferior adjacent segment increased in 12 cases.

CONCLUSIONS

CC significantly reduces the motion of the cervical spine and increases the adjacent segment mobility at intermediate follow-up. The inferior adjacent segment shows greater compensation of motion as compared to the superior adjacent segment in our series. Adjacent segment degeneration as estimated by Nathan's grade was seen in one-third of the cases.

Laser-assisted anterior cervical corpectomy versus posterior laminoplasty for cervical myelopathic patients with multilevel ossification of the posterior longitudinal ligament

OBJECTIVE

This study reports on the comparative results of a series of patients with multilevel cervical ossification of the posterior longitudinal ligament (OPLL) who were treated with laser-assisted anterior corpectomy or laminoplasty.

METHODS

Forty-eight patients (21 patients with anterior corpectomy and 27 patients with laminoplasty) with cervical OPLL involvement of three or more vertebral bodies were retrospectively reviewed. Both pre- and postoperatively neurological status was graded according to the Nurick grading system. The anteroposterior (AP) diameter change at the narrowest part of the spinal canal, the change in the regional and the overall cervical Cobb's angle, and the change in cervical range of motion (ROM) were all measured. The mean follow-up periods were 21.8 mo and 29.1 mo for the corpectomy and laminoplasty patients, respectively.

RESULTS

The mean changes in the pre- to postoperative Nurick grades were 1.9 for the corpectomy group and 1 for the laminoplasty group (p < 0.05). The mean changes in the pre- to postoperative spinal canal AP diameters were 9.1 mm and 4.11 mm, respectively, for the corpectomy group and the laminoplasty group (p < 0.05). The mean changes of the regional Cobb's angle were 1.7 degrees and -3.1 degrees (p = 0.06), and the mean changes of the overall cervical Cobb's angle were 1.1 degrees and -1.6 degrees , respectively, for the corpectomy group and the laminoplasty group (p > 0.05). The changes in the cervical degree of ROM were -19.6 degrees and -19.7 degrees , respectively, for the corpectomy group and the laminoplasty group (p > 0.05).

CONCLUSIONS

Direct decompression of the spinal cord by laser-assisted anterior cervical corpectomy was shown to be a better surgical option on long-term follow-up, yielding more recovery of neurological deficits, achieving adequate decompression of the spinal canal, and preventing the development of regional kyphosis at the operated level of the spine, in patients with multilevel cervical OPLL.

Cervical spondylotic myelopathy treated by oblique corpectomy: a prospective study

OBJECTIVE

Anterolateral partial oblique corpectomy (OC) aims to decompress the cervical spinal cord without subsequent fusion and saves the patient from graft-, instrument-, and fusion-related complications. Although it is a promising technique, there are few studies dealing with its efficacy and safety.

METHODS

In this prospective study, 40 consecutive patients underwent an OC (one to four levels from C3 to C7) for cervical spondylotic myelopathy; they ranged in age from 43 to 78 years (mean, 55 yr). The average follow-up period was 59 months (range, 24-98 mo). Clinical and radiological data were analyzed to assess the results and find possible factors related to outcomes.

RESULTS

Thirty-seven (92.5%) of the 40 patients improved by the 6-month follow-up examination according to the Japanese Orthopedic Association score. The improvement was the most prominent in lower extremity dysfunction. Recovery was positively correlated with the preoperative Japanese Orthopedic Association score (r = 0.37, P = 0.018). Permanent Horner's syndrome developed in four patients (10%). During the long-term follow-up period, neurological improvement was maintained and there were no signs of postoperative instability, posture change, or axial pain.

CONCLUSION

OC for treating multilevel cervical spondylotic myelopathy achieved good results with a low morbidity rate. The results of the current study suggest that OC is a good alternative to conventional median corpectomy and fusion techniques in selected cases.

USE OF VENTRAL PLATES FOR CERVICAL ARTHRODESIS

OBJECTIVE

Ventral cervical plates are used to increase the immediate postoperative rigidity of the spine after decompressive and reconstructive procedures. The evidence supporting this practice is reviewed.

METHODS

A computerized literature search of the database of the National Library of Medicine was conducted using PubMed. All relevant articles were reviewed and a critique was performed to explore the utility of ventral cervical plating.

RESULTS

Several randomized controlled trials of ventral cervical discectomy versus ventral cervical discectomy and fusion were identified. Three randomized controlled trials that included a differentiation between anterior cervical decompression and fusion, with and without plating, were identified. Many retrospective series, technical reports, and topical reviews were also identified.

CONCLUSION

There is little support in the literature for the medical usefulness of ventral cervical plates after single-level cervical fusion. There may, however, be a cost-benefit advantage to the use of such devices. In multilevel procedures and in the setting of traumatic instability, there seems to be an advantage to the use of cervical plates.

Laminoplasty: a review of its role in compressive cervical myelopathy

BACKGROUND CONTEXT

The currently accepted surgical treatments for compressive cervical myelopathy include both anterior and posterior decompression. Anterior approaches including multilevel discectomy with fusion or vertebral corpectomy with strut grafting, both with and without instrumentation, have enjoyed successful outcomes, but have been associated with select postoperative complications. Laminoplasty has been developed to decompress the spine posteriorly while avoiding the spinal destabilization seen after laminectomy.

PURPOSE

The purpose of this article is to provide a review of the various techniques, biomechanical basis, predictive value of imaging modalities, clinical outcomes, and postoperative complications associated with cervical laminoplasty.

STUDY DESIGN

A review of the literature.

METHODS

A comprehensive literature review using Medline was performed identifying relevant articles that addressed the techniques, clinical outcomes, and complications after cervical laminoplasty, as well as preoperative radiographic predictors of outcome.

RESULTS

The various modifications of cervical laminoplasty have generally been associated with excellent clinical outcomes when used for myelopathy secondary to cervical spondylosis or ossification of the posterior longitudinal ligament (OPLL). Recent long-term studies have identified issues with this technique including axial neck pain, canal restenosis, nerve root palsy, diminished cervical motion, and loss of cervical lordotic alignment.

CONCLUSIONS

Cervical laminoplasty remains a reliable procedure for posterior decompression of the spine, but the optimal approach to cervical myelopathy must take into account both patient and disease characteristics, as well as the capabilities and experience of the surgeon.

Hollow cylindrical polymethylmethacrylate strut for spinal reconstruction after single-level cervical corpectomy

Object

This prospective study was conducted to assess the safety of using a cylindrical polymethylmethacrylate (PMMA) strut for fusion and reconstruction of the cervical spine after single-level cervical corpectomy. The authors describe the clinical results obtained in patients after surgery.

Methods

Fifty-four patients underwent single-level cervical corpectomy, fusion, and spinal reconstruction that involved the placement of hollow cylindrical PMMA struts. In each patient, the spine was reinforced with anterior cervical plates. The PMMA struts were filled with autologous bone obtained from the resected vertebral body. Follow-up radiographic evaluation involved plain lateral dynamic radiographs and computed tomography (CT) scans. Neurological status was assessed pre- and postoperatively using the Nurick Scale. A total of 46 patients (85.1%) attended follow-up visits for a minimum of 2 years. Spinal stability was documented in all patients on 12-month plain dynamic lateral radiographs; in 37 patients (80.4%), complete osseous fusion was demonstrated on the 12-month CT reconstructions. In the remaining nine patients, complete fusion had been achieved by 24 months. The overall mean preoperative Nurick grade was 2.94 ± 0.97, and this improved significantly to 1.71 ± 0.77 (p < 0.05) by 24 months. There were no complications related to the hollow cylindrical PMMA strut.

Conclusions

The findings of this preliminary study indicate that hollow cylindrical PMMA struts can be safely used in cervical fusion after single-level corpectomy and that the clinical results are satisfactory. The hollow cylindrical PMMA strut is a good substitute for spinal reconstruction and fusion when combined with plate fixation in patients who have undergone anterior cervical single-level corpectomy.

Maintenance of graft compression in the adult cervical spine

It is generally advised that the graft inserted in adult cervical spine should be pre-loaded with a compressive force or that the screws are inserted in a divergent orientation, in order to maximise compression and the chance of graft incorporation (Truumees et al. in Spine 28:1097-1102, 2003). However, there is little evidence that a compressive force is maintained once the force applicator has been removed, or that the divergent screws enhance compression. This study compared the maintenance of applied pre-load force, across cervical spine graft, between standard anterior plating technique with pre-load and divergent screws and a novel plate technique, which allows its application prior to removal of the force applicator. Six intact adult cadaveric human cervical spines were exposed by standard surgical technique. A Casper type distracter was inserted across the disc space of interest, the disc was removed. In 14 experiments, following the disc removal, an autologous iliac crest bone graft was inserted under distraction, together with a strain gauge pressure transducer. A resting output from the transducer was recorded. The voltage output has a linear relationship with compressive force. A standardised compressive force was applied across the graft through the "Casper type" distracter/compressor (7.5 kg, torque). The pre-load compressive force was measured using a torque drill. Then two different procedures were used in order to compare the final applied strain on the bone graft. In eight experiments (procedure 1), the "Casper type" distracter/compressor was removed and a standard anterior cervical plate with four divergent screws was inserted. In six experiments (procedure 2), a novel plate design was inserted prior to removal of the distracter/compressor, which is not possible with the standard plate design. A final compressive force across the graft was measured. For the standard plate construct (procedure 1), the applied compression force is significantly greater than resting (SO/SC)--P=0.01, but the compression force is not maintained once the compressor is removed (SO/SR)--P=0.27. Final bone graft compression after plate insertion is not significantly different to the resting state (SO/SF)--P=0.16 (Wilcoxon's sign test for paired observation). Application of the plate tended to offload the graft; the final compressive force is 170+/-100% less than the resting force. None of the applied force was maintained (mean 9.5+/-8.8%). For the new plate (procedure 2), the end compressive force (SF) measured across the graft was greater than the resting force (SO) (P<0.001). Further, the novel plate application increased the compressive force on the graft by 712+/-484%. The final bone graft compression using a novel plate, which allows its application prior to removal of the force applicator, is significant (SO/SF)--P=0.01. Here, 77+/-10% of the applied pre-load was maintained. The difference between the plates is significant (P<0.001). Conclusions are as follows: (1) Applied pre-load is not maintained across a graft once the force applicator is removed. (2) Divergent screws with a plate do not compress graft and rather tend to offload it. (3) Compressive force may be maintained if the plate is applied prior to the force applicator removal.

Functional outcome after central corpectomy in poor-grade patients with cervical spondylotic myelopathy or ossified posterior longitudinal ligament

OBJECTIVE

We studied the long-term functional outcome in poor-grade patients (Nurick Grades 4 and 5) with cervical spondylotic myelopathy (CSM) or ossified posterior longitudinal ligament after central corpectomy (CC). We sought to determine whether there were any prognostic factors that could predict functional outcome in these patients.

METHODS

Functional outcome data were collected for 72 patients (68 men and 4 women; mean age, 49.7 yr; range, 30-67 yr) with CSM (60 patients) or OPLL (12 patients) of Nurick Grades 4 (55 patients) and 5 (17 patients). Uninstrumented CC was performed at 1 level in 12 patients, at 1 level combined with a discoidectomy at another level in 4 patients, at 2 levels in 50 patients, and at 2 levels plus a discoidectomy in 5 patients. The age at presentation (< or =50 yr or >50 yr), grade before surgery (4 or 5), the number of levels operated (1 or >1), diagnosis (CSM or ossified posterior longitudinal ligament), and duration of myelopathic symptoms (< or =12 mo or >12 mo) were studied for their effect on the functional outcome noted at the last follow-up. Functional outcome was graded as poor (no change in Nurick grade), fair (improvement of one Nurick grade), good (improvement of two Nurick grades), and cure (follow-up Nurick grade of 0 or 1).

RESULTS

The follow-up ranged from 9 to 104 months (mean, 36.3 mo). One patient died 3 weeks after CC after surgery for a perforated duodenal ulcer. There was transient operative morbidity in 12 patients (16.9%). The mean Nurick score improved from 4.24 to 2.47 (P < 0.001). Of the 54 patients (76%) who improved in their Nurick grade, the functional outcome was graded as fair in 13 patients (18.3%), good in 24 patients (33.8%), and cure in 17 patients (23.9%). The functional outcome was poor in 17 patients (23.9%). Functional improvement after CC was uniformly correlated with myelopathic symptoms of 12 months' duration or shorter. The other favorable prognostic indicators for improvement after CC were a diagnosis of CSM and preoperative Nurick Grade 5; however, patients with a preoperative Nurick grade of 4 were more likely to experience a cure.

CONCLUSION

More than three-fourths of patients with poor-grade CSM improve in their functional status after CC, with nearly 24% of patients obtaining a cure. Because patients with a duration of myelopathic symptoms of 12 months or less had the best functional outcome, early decompressive surgery should be offered to patients with poor-grade CSM.

The biomechanical effects of cervical multilevel oblique corpectomy

STUDY DESIGN

A repeated-measures flexibility test was performed in vitro using human cadaveric spines.

OBJECTIVES

To compare changes in cervical biomechanics associated with multilevel oblique corpectomy and standard grafted corpectomy with or without plating.

SUMMARY OF BACKGROUND DATA

Standard multilevel plated and unplated corpectomies are susceptible to instability in vitro. The authors are unaware of any previous research on the biomechanics of multilevel oblique corpectomy. METHODS.: Six human cadaveric cervical spine specimens (C3-T1) were tested: 1) normal; 2) after 2-level multilevel oblique corpectomy; 3) after expanding multilevel oblique corpectomy to represent standard grafted and plated corpectomy; and 4) after removing the anterior plate. Pure moments were applied to induce flexion, extension, lateral bending, and axial rotation while recording motion stereophotogrammetrically.

RESULTS

Compared to normal, the range of motion after multilevel oblique corpectomy increased 15% during flexion, 18% during extension, 11% during lateral bending, and 18% during axial rotation. These increases were about one-third of the increases observed after standard corpectomy without plating. Multilevel oblique corpectomy caused few alterations in locations of axes of rotation and coupling patterns, whereas standard corpectomy with or without plating significantly altered these parameters in several instances.

CONCLUSIONS

Multilevel oblique corpectomy (without graft) induced significantly less instability and altered kinematics less than standard unplated corpectomy with graft. Multilevel oblique corpectomy allowed significantly more motion than standard plated corpectomy with graft. However, the goal of standard corpectomy is fusion. Our results indicate that plating significantly limits spinal mobility after 2-level corpectomy, improving the environment for fusion.

Anterior decompression for cervical spondylotic myelopathy

Cervical spondylotic myelopathy is a clinical entity that manifests itself due to compression and ischemia of the spinal cord. The goal of treatment is to decompress the spinal cord and stabilize the spine in neutral, anatomical position. Since the obstruction and compression of the cord are localized in front of the cord, it is obvious that an anterior surgical approach is the preferred one. The different surgical procedures, complications, and outcome are discussed here.

Surgery for postarthrodesis adjacent–cervical segment degeneration

Anterior cervical decompression and fusion has gained popularity because of its applicability to a variety of cervical spine disorders. The authors of long-term follow-up studies have demonstrated the development of degenerative changes in segments adjacent to fusion. So-called adjacent-segment disease causes symptomatic deterioration in up to 25% of the patients who have undergone anterior cervical decompression and fusion for cervical spondylotic myelopathy. The causes of this condition are debated in the literature. The authors provide a review of the available literature on the pathogenesis, prevention, and treatment of postarthrodesis adjacent-segment degenerative disease.

Graft migration or displacement after multilevel cervical corpectomy and strut grafting

STUDY DESIGN

A retrospective review of consecutive patients with graft migration or displacement after anterior cervical corpectomy surgery was performed.

OBJECTIVES

To examine the associated risk factors and results of treatment among patients who sustained graft displacement or migration after anterior cervical corpectomy surgery.

SUMMARY OF BACKGROUND DATA

Graft migration or displacement after anterior cervical corpectomy is a potential complication that may require revision surgery, but because of the low incidence, the factors associated with graft movement and the results of treatment are not well defined.

METHODS

All patients who had undergone a cervical corpectomy were examined for graft migration or displacement. None of the patients had a previous cervical laminectomy or prior posterior cervical surgery. All the patients were treated with autogenous strut grafting after decompression.

RESULTS

Over a 25-year period, 249 consecutive patients underwent one- to five-level anterior cervical corpectomies and strut grafting. All the patients were fused using autogenous bone grafts (iliac crest or fibula). During the postoperative period, 16 of the patients (10 women and 6 men; average age, 61.4 years) experienced migration of their grafts. The average follow-up period was 4.7 years (range, 2-12 years). The graft migration rates increased with more levels of fusion (odds ratio of 1.65 for having a displaced graft with each additional level): 4 of 95 single-level grafts, 4 of 76 two-level grafts, 7 of 71 three-level grafts, and 1 of 6 for four-level grafts. Of the 16 patients with graft migration, 14 had procedures involving a corpectomy of C6 with a fusion inferiorly extending to the C7 vertebral body (P = 0.001, statistically significant difference). Of these 16 patients, 5 underwent revision surgeries acutely for displacement and associated fracture of the inferior graft and vertebral body junction. None of the patients sustained a neurologic or respiratory complication as a result of graft migration ordisplacement. All of the patients went on to successfulfusion.

CONCLUSIONS

This study demonstrated that a greater number of vertebral bodies removed and a longer graft are directly related to an increased frequency of graft displacement. Graft displacement may require revision surgery, but no patient in this study experienced a permanent adverse result from this complication. Corpectomies involving a fusion ending at the C7 vertebral body were associated with a higher rate of graft migration.

Vertebral autograft used as bone transplant for anterior cervical corpectomy: technical note

OBJECTIVE

In this prospective patient study, we used a surgical technique for autograft bone fusion during anterior cervical corpectomy (ACC) in patients experiencing cervical spondylotic myelopathy. We packed the resected bone material of the corpectomy into a titanium mesh cage. To evaluate the efficacy of our autograft technique, we analyzed the results according to neurological outcome, radiological outcome, and complications.

METHODS

Between 1995 and 1998, 27 ACC operations were performed for cervical spondylotic myelopathy caused by multisegmental cervical spondylosis. In all patients, decompression of the cervical canal and/or spinal nerve roots was performed by a median cervical corpectomy by an anterior approach. After the ACC was completed, a titanium mesh cage, which was variable in diameter and length, was filled with morselized and impacted bone material from the cervical corpectomy and was then implanted. An anterior cervical plate was placed in all patients to achieve primary stability of the cervical vertebral column. Age, sex, pre- and postoperative myelopathy, number of decompressed levels, radiological results, and complications were assessed. The severity of myelopathy was graded according to the scoring system of the Japanese Orthopaedic Association.

RESULTS

Symptomatic improvement of neurological deficits was achieved in 80% of the patients. The mean preoperative Japanese Orthopaedic Association score improved from 13.1 to 15.2 postoperatively (P < 0.05). No patient demonstrated worsening of myelopathic symptoms. Radiological follow-up studies demonstrated complete bony fusion in all patients. A vertical movement of 2.25 +/- 0.43 mm of the titanium cage into the adjacent vertebral bodies was observed in 24 patients. In patients with either a lordotic or neutral cervical spinal axis postoperatively, the axis remained unchanged during the entire follow-up period.

CONCLUSION

The results of this study demonstrate that transplantation of autograft bone material harvested during the ACC integrated well in the cage and in the adjacent vertebral bodies. Thus, complications associated with explantation of autograft material from other donor sites, e.g., the iliac crest, could be avoided. The early postoperative and midterm follow-up periods provided no evidence of morphological or functional instability of the operated cervical segments when this autograft technique was used in combination with cervical instrumentation.

Anterior cervical corpectomy and strut graft fusion using a different method

BACKGROUND CONTEXT

Strut graft fusion after corpectomy is frequently indicated for certain pathologies in the cervical spine. The "key-hole" technique and "dove-tail" technique are the popular methods used to insert the strut graft at present. Segmental collapse secondary to seating of the graft on cancellous bone and cord injury from placement or dislodgement the graft are our concerns. Our method was designed to solve these possible problems without affecting the arthrodesis.

PURPOSE

To evaluate the results of this method that allows the graft to seat on both the hard end plate and cancellous bone of the upper and lower contacting vertebrae in a easy and safe way after varying levels of corpectomy in the cervical spine.

STUDY DESIGN

A retrospective clinical and radiographic study conducted by an independent observer was performed on 23 patients treated with this different strut grafting method after cervical corpectomy, with at least 2 years of follow-up.

PATIENT SAMPLE

A total of 23 patients from 1983 to 1994 underwent fusion using our strut grafting method with fibular allograft packed with autogenous bone. No augmented internal instrumentation was used in all these patients. The patients with an incomplete record or less than 2 years of follow-up were excluded beforehand.

OUTCOME MEASURES

Clinical outcome was assessed by a score based on three factors: neck pain, dependence on medicine and ability to return to work. The total score of these factors was seven. A score from 0 to 3 was defined as satisfactory, and a score from 4 to 7 was defined as unsatisfactory. The result of graft fusion, collapse of interbody height and loss of lordotic angle corrected by the graft were evaluated through the radiographic studies.

METHODS

The operative technique creates a notch in the anterior cortex and end plate of the respective superior and inferior vertebraes. Cylinder allograft filled with autogenous cancellous bone was used as bone graft for all patients. The bone graft is cut with corresponding pegs at both ends. The graft is inserted into the corpectomy space with the pegs inserted into the notches and the remainder of the graft placed onto the preserved superior and inferior bony end plates.

RESULTS

Twenty patients achieved successful fusion (87%). On average, the loss of anterior and posterior interbody height was 2.79 mm and 2.93 mm, respectively. The average loss of lordotic correction was 2.83 degrees. Eighty-three percent achieved satisfactory clinical outcomes. There were no neurologic injuries encountered during the operation. Partial graft dislodgment occurred in two patients (8.7%).

CONCLUSIONS

This different method of strut grafting after cervical corpectomy has proven its safety and efficacy in its fusion and clinical results.

Surgical options for the treatment of cervical spondylotic myelopathy

Cervical spondylotic myelopathy is a disease of the cervical spinal cord that results from circumferential compression of the degenerative cervical spine, often in a congenitally narrow spinal canal. Surgical recommendations must be based on patient characteristics, symptoms, function, and neuroradiologic findings. ACDF is an excellent option for one- or two-level spondylosis without retrovertebral disease. Anterior corpectomy and strut grafting may provide an improved decompression and is ideal for patients with kyphosis or neck pain. Laminectomy historically yields poor results from late deformity and late neurologic deterioration but yields improved results with good surgical technique. Laminoplasty was developed to address cervical stenosis of three or more segments and compares favorable with anterior corpectomy and fusion for neurologic recovery. Laminoplasty has a lower complication rate than corpectomy and strut grafting but has a higher incidence of postoperative axial symptoms.

Role of corpectomy in cervical spondylosis

The management of cervical spondylosis has evolved over the past several decades. Surgical decompressive and stabilization techniques have become more widely accepted for use in patients with intractable pain or neurological deficits. Advances in neuroimaging, surgical technique, and surgery-related technology including the operating microscope and anterior fixation devices have all contributed to the expanding role of surgery for the treatment of this condition. In this paper the author will focus on the role of corpectomy as a surgical option for managing cervical spondylosis.

Cervical spinal stenosis: outcome after anterior corpectomy, allograft reconstruction, and instrumentation

OBJECT

The authors undertook a retrospective single-institution review of 261 patients who underwent anterior cervical corpectomy, reconstruction with allograft fibula, and placement of an anterior plating system for the treatment of cervical spinal stenosis to assess fusion rates and procedure-related complications.

METHODS

Between October 1989 and June 1995, 261 patients with cervical stenosis underwent cervical corpectomy, allograft fibular bone fusion, and placement of instrumentation for spondylosis (197 patients), postlaminectomy kyphosis (27 patients), acute fracture (25 patients), or ossification of the posterior longitudinal ligament (12 patients). All patients suffered neck pain and cervical myelopathy or radiculopathy refractory to medical management. Of the procedures, 133 involved a single vertebral level (two disc levels and one vertebral body), 96 involved two levels, 31 involved three levels, and a single patient underwent a four-level procedure. Clinical and radiographic outcomes were assessed postoperatively and at 6-month intervals. The mean follow-up period was 25.7 months (range 24-47 months). Successful fusion was documented in 226 patients (86.6%). A stable, fibrous union developed in 33 asymptomatic patients (12.6%), whereas an unstable pseudarthrosis in two patients (0.8%) required reoperation. There were no cases of infection, spinal fluid leakage, or postoperative hematoma. Complications included transient unilateral upper-extremity weakness (two patients), dysphagia (35 transient and seven permanent), and hoarseness (35 transient and two permanent). In 14 patients (5.4%) radiological studies demonstrated evidence of hardware failure.

CONCLUSIONS

Cervical corpectomy with fibular allograft reconstruction and anterior plating is an effective means of achieving spinal decompression and stabilization in cases of anterior cervical disease. Symptomatic improvement was achieved in 99.2% of patients. In their series the authors found a fusion rate of 86.6% and rates of permanent hoarseness of 3.4%, dysphagia of 0.7%, and an instrumentation failure rate of 5.4%.

Single-stage anterior-posterior decompression and stabilization for complex cervical spine disorders

OBJECT

To evaluate the applicability and safety of single-stage combined anterior-posterior decompression and fusion for complex cervical spine disorders, the authors retrospectively reviewed 72 consecutive procedures of this type performed using a uniform technique at a single center.

METHODS

The indications for decompression and stabilization included: postlaminectomy kyphosis (15 patients), trauma (19 patients), spondylosis and congenital stenosis (32 patients), and ossification of the posterior longitudinal ligament (six patients). All patients underwent anterior cervical corpectomies in which allograft fibula and plates were placed, with 89% of patients undergoing two- or three-level procedures (range one-four levels). Lateral mass plating with autograft (morselized iliac crest) fusion was performed in all patients while the same anesthetic agent was still in effect. A hard cervical collar was used postoperatively in all patients (mean 13 weeks). All patients were followed for a minimum of 2 years (mean 29 months). Fusion was determined to be successful in all 72 patients (100%). Although the short-term morbidity rate reached 32%, the significant long-term morbidity rate was only 5%. At the 2-year follow-up examination, anterior cervical plate dislodgment was seen in one patient, and 16 of the 516 lateral mass screws implanted were observed to have partially backed out. However, there were no cases of nerve root injury, strut graft extrusion, or anterior plate or screw fracture. There were no clinically significant hardware complications and no patient required repeated operation.

CONCLUSIONS

The combined single-stage anterior-posterior decompression, reconstruction, and instrumentation procedure represents a viable option in the treatment of a select group of patients with complex cervical spinal disorders. The technique provides immediate rigid stabilization of the cervical spine, prevents anterior plate failure or strut graft extrusion, and eliminates the need for halo immobilization postoperatively. Furthermore, a higher rate of fusion is achieved with this combined approach than with the anterior approach alone.

Single-stage anterior–posterior decompression and stabilization for complex cervical spine disorders

Object

To evaluate the applicability and safety of single-stage combined anterior–posterior decompression and fusion for complex cervical spine disorders, the authors retrospectively reviewed 72 consecutive procedures of this type performed at their respective institutions.

Methods

The indications for decompression and stabilization included: postlaminectomy kyphosis (15 patients), trauma (19 patients), spondylosis and congenital stenosis (32 patients), and ossification of the posterior longitudinal ligament (six patients). All patients underwent anterior cervical corpectomies in which allograft fibula and plates were placed, with 89% of patients undergoing two- or three-level procedures (range one–four levels). Lateral mass plating with autograft (morselized iliac crest) fusion was performed in all patients while the same anesthetic agent was still in effect. A hard cervical collar was used postoperatively in all patients (mean 13 weeks). All patients were followed for a minimum of 2 years (mean 29 months).

Fusion was determined to be successful in all 72 patients (100%). Although the short-term morbidity rate reached 32%, the significant long-term morbidity rate was only 5%. At the 2-year follow-up examination, anterior cervical plate dislodgment was seen in one patient, and 16 of the 516 lateral mass screws implanted were observed to have partially backed out. However, there were no cases of nerve root injury, strut graft extrusion, or anterior plate or screw fracture. There were no clinically significant hardware complications and no patient required repeated operation.

Conclusions

The combined single-stage anterior–posterior decompression, reconstruction, and instrumentation procedure represents a viable option in the treatment of a select group of patients with complex cervical spinal disorders. The technique provides immediate rigid stabilization of the cervical spine, prevents anterior plate failure or strut graft extrusion, and eliminates the need for halo immobilization postoperatively. Furthermore, a higher rate of fusion is achieved with this combined approach than with the anterior approach alone.

A new surgical technique: open-window corpectomy in the treatment of ossification of the posterior longitudinal ligament and advanced cervical spondylosis: technical note

OBJECTIVE

To achieve satisfactory cervical spinal cord decompression with minimal removal of bone.

METHODS

The open-window corpectomy technique is designed to remove a minimal amount of bone and achieve satisfactory decompression. With the use of a high-speed drill under a surgical microscope, only the dorsal surface of the corpus is removed after appropriate microdiscectomies. This leaves the anterior and the lateral portions of the vertebral corpus intact.

RESULTS

In a 15-month period, a total of 11 patients were treated with this technique. Five patients improved, and the remaining six patients remained the same neurologically during a mean follow-up period of 8.3 months. No complications were observed in any patients.

CONCLUSION

The open-window corpectomy provides satisfactory spinal cord decompression in a biomechanically sound manner.

Complications of buttress plate stabilization of cervical corpectomy

STUDY DESIGN

A retrospective analysis of 14 patients treated with cervical corpectomy and buttress plate fixation.

OBJECTIVES

To determine the complications of buttress plate fixation following multilevel cervical corpectomies.

SUMMARY OF BACKGROUND DATA

Buttress plate fixation of multilevel cervical corpectomy has recently been reported. Biomechanical data suggests that it is preferable to long plates spanning the entire corpectomy site. There are no clinical studies that have specifically addressed the complications of this type of plate fixation.

METHODS

The records and radiographs of all patients who had undergone cervical buttress plate fixation following anterior cervical corpectomy for myelopathy were independently reviewed. Twelve of the patients had three-level corpectomies and two had two-level corpectomies. All patients had placement of a short plate at the inferior end of the construct with sufficient overhang to act as a buttress against graft extrusion. Three patients underwent posterior cervical fusion in addition to the anterior procedure.

RESULTS

Graft extrusion. One patient had complete graft extrusion on the third post-operative night. A second patient who had undergone circumferential fusion had minimal plate dislodgement secondary to graft settling. Pseudarthrosis. Three patients had pseudarthroses. Two of these required revision posterior surgery. Neurologic. None of the patients suffered neurologic complications. With the exception of the one patient who died, the rest of the patients all improved by at least one Nurick grade.

CONCLUSION

The most catastrophic complication in the present series was plate dislodgement causing airway compromise and eventually resulting in death. Surgeons who utilize these types of buttress plates without additional posterior instrumentation should be aware of the potential complications of buttress plate fixation.

Anterior cervical reconstruction using titanium cages with anterior plating

STUDY DESIGN

A preliminary outcome assessment study of titanium cage implants with anterior cervical plating in anterior cervical reconstruction.

OBJECTIVES

To evaluate the efficacy and safety of using titanium cage implants and anterior plating in cervical reconstruction.

SUMMARY OF BACKGROUND DATA

Anterior decompression and interbody fusion is a widely accepted surgical treatment for patients with cervical spondylosis. Tricortical iliac crest autograft has been the gold standard but is associated with morbidity at the bone graft donor site, whereas allograft fibula is associated with pseudarthrosis. Problems such as pseudarthrosis, graft collapse, and extrusion still persist with the accepted method of harvesting and implanting bone autografts.

METHODS

Thirty-four patients were treated by channel corpectomy followed by placement of a titanium cage packed with autogenous bone graft from the vertebral bodies to reconstruct the anterior column. An anterior cervical plate was added in 30 of 34 cases that involved decompression of two or more levels. The follow-up period ranged from 24 to 56 months, with an average follow-up period of 32 months, and included examination and radiography.

RESULTS

Six months after surgery, there was radiographic evidence of fusion in 97% of the patients. Eighty-eight percent of the patients (30 of 34) did not experience any complications (neither cage dislodgment nor hardware failure). Four patients had complications that included pseudarthrosis (1), extruded cage (1), cage in kyphosis (1), and radiculopathy (1).

CONCLUSIONS

Titanium cages provide immediate strong anterior column support with minimum hardware complications and avoid bone graft-site morbidity. Titanium cages, with concomitant use of anterior plating, offer an effective and safe alternative to bone autografts.

Multisegmental cervical spondylotic myelopathy and radiculopathy treated by multilevel oblique corpectomies without fusion

OBJECTIVE

The description of the technique of multilevel oblique corpectomy (MOC) without fusion in the treatment of spondylotic myelopathy and radiculopathy and the analysis of the results of this technique from a series of 101 cases are presented.

METHODS

MOC is performed using an anterolateral approach with control of the vertebral artery. The vertebral bodies are drilled obliquely from the lateral side toward the opposite posterolateral corner. More than half of the vertebral bodies are preserved, and no fusion procedure is required. The series of patients from 1992 through 1997 included 54 men and 47 women, with an average age of 57.9 years, who presented with myelopathy (n = 66) or radiculopathy (n = 35). MOC was realized on one to five levels from C2-C3 to C7-T1. Follow-up data were obtained by performing dynamic roentgenography, computed tomography, and magnetic resonance imaging 2 months, 1 year, and 3 years after surgery.

RESULTS

The results (Japanese Orthopedic Association score) were improvement in 82% of the patients, worsening in 8%, and stabilization in 10%. Better results were observed in younger patients (<50 yr). No relation between results and duration of symptoms or number of levels could be established. One death occurred as a result of multiorgan failure. No late deterioration was observed; however, three patients with particular features showed delayed instability requiring fusion.

CONCLUSION

MOC is a safe and efficient technique. It must be applied for patients with anterior compression and straight or kyphotic axis of the spine. No fusion is required regardless of the number of levels, providing there are no soft discs and there is no preoperative instability.

Anterior cervical corpectomy for cervical spondylotic myelopathy

OBJECTIVE

To evaluate the efficacy of anterior surgery for the treatment of cervical spondylotic myelopathy, we have reviewed our experience with anterior cervical corpectomy (ACC) at the University of Florida, specifically analyzing neurological outcomes and complications. These results have been compared with historical control subjects receiving laminectomy or "no treatment."

METHODS

Between 1982 and 1992, 93 ACC operations were performed for the primary diagnosis of cervical spondylotic myelopathy. This consecutive series of patients was reviewed retrospectively. Age, gender, pre- and postoperative myelopathy severity, number of levels decompressed, and neurological complications were assessed. Myelopathy severity was graded using the Nurick myelopathy grading system. The average follow-up period was 39 months (range, 2-137 mo).

RESULTS

Symptomatic improvement was achieved for 92% of patients (F = 28.9, df = 2172, P < 0.001). Nurick scores reflected improvement for 86% of patients, with the conditions of 13% remaining unchanged and only one patient showing worsening. Preoperative myelopathy severity was weakly correlated with age (P < 0.05) but was not correlated with gender or number of levels decompressed. Similarly, postoperative myelopathy severity was not significantly correlated with age, gender, preoperative myelopathy severity, or number of levels decompressed. ACC-treated patients showed an average improvement of 1.24 points on the Nurick scale, compared with an improvement of 0.07 points for patients treated with laminectomy (P < 0.001) and a deterioration of 0.23 points for patients undergoing conservative treatment (P < 0.001). Complications were slightly more likely to occur in older patients (P < 0.05). The number of levels decompressed was not significantly correlated with complications. Only one permanent neurological complication was seen in this series of patients.

CONCLUSION

We conclude that ACC is a safe and effective treatment for cervical spondylotic myelopathy. In an average of 39 months, ACC showed improved results in terms of myelopathy scores, compared with historical control subjects receiving either no treatment or laminectomy. Age, gender, preoperative myelopathy severity, and extent of disease were not negative predictors of clinical outcomes.

Anterior cervical decompression and arthrodesis for the treatment of cervical spondylotic myelopathy. Two to seventeen-year follow-up

We reviewed the cases of 108 patients with cervical spondylotic myelopathy who had been managed with anterior decompression and arthrodesis at our institution. Operative treatment consisted of anterior discectomy, partial corpectomy, or subtotal corpectomy at one level or more, followed by placement of autogenous bone graft from the iliac crest or the fibula. At the latest follow-up examination, thirty-eight of the eighty-two patients who had had a preoperative gait abnormality had a normal gait, thirty-three had an improvement in gait, six had no change, four had improvement and later deterioration, and one had a worse gait abnormality. Of the eighty-seven patients who had had a preoperative motor deficit, fifty-four had complete recovery; twenty-six, partial recovery; six, no change; and one had a worse deficit. The average grade according to the system of Nurick improved from 2.4 preoperatively to 1.2 (range, 0.0 to 5.0) postoperatively. A pseudarthrosis developed in sixteen patients, thirteen of whom had had a multilevel discectomy. Only one of thirty-eight arthrodeses that had been performed with use of a fibular strut graft was followed by a non-union. An unsatisfactory outcome with respect to pain was significantly associated with pseudarthrosis (p < 0.001). The development of complications other than non-union was associated with a history of one previous operative procedure or more (p = 0.005). Recurrent myelopathy was rare, but when it occurred it was associated with a pseudarthrosis or stenosis at a new level. The strongest predictive factor for recovery from myelopathy was the severity of the myelopathy before the operative intervention--that is, better preoperative neurological function was associated with a better neurological outcome. Anterior decompression and arthrodesis with autogenous bone-grafting can be performed safely, and is associated with a high rate of neurological recovery, functional improvement, and pain relief, in patients who have cervical spondylotic myelopathy.

Multilevel anterior cervical corpectomy and fibular allograft fusion for cervical myelopathy

This study was conducted to determine the safety and efficacy of multilevel anterior cervical corpectomy and stabilization using fibular allograft in patients with cervical myelopathy. Thirty-six patients underwent this procedure for cervical myelopathy caused by spondylosis (20 patients), ossified posterior longitudinal ligament (four patients), trauma (one patient), or a combination of lesions (11 patients). The mean age (+/- standard deviation) of the patients was 58 +/- 10 years and 30 of the patients were men. The mean duration of symptoms before surgery was 30 +/- 6 months and 11 patients had undergone previous surgery. Prior to surgery, the mean Nurick grade of the myelopathy was 3.1 +/- 1.4. Seventeen patients also had cervicobrachial pain. Four vertebrae were removed in six patients, three in 19, and two in 11 patients. Instrumentation was used in 15 cases. The operative mortality rate was 3% (one patient) and two patients died 2 months postoperatively. Postoperative complications included early graft displacement requiring reoperation (three patients), transient dysphagia (two patients), cerebrospinal fluid leak treated by lumbar drainage (three patients), myocardial infarction (two patients), and late graft fracture (one patient). One patient developed transient worsening of myelopathy and three developed new, temporary radiculopathies. All patients achieved stable bone union and the mean Nurick grade at an average of 31 +/- 20 months (range 0-79 months) postoperatively was 2.4 +/- 1.6 (p < 0.05, t-test). Cervicobrachial pain improved in 10 (59%) of the 17 patients who had preoperative pain and myelopathy improved at least one grade in 17 patients (47%; p < 0.05). Twenty-six surviving patients (72%) were followed for more than 24 months and stable, osseous union occurred in 97%. These results show that extensive, multilevel anterior decompression and stabilization using fibular allograft can be achieved with a perioperative mortality and major morbidity rate of 22% and with significant improvement in pain and myelopathy.

Anterior cervical allograft arthrodesis and instrumentation: multilevel interbody grafting or strut graft reconstruction

This retrospective study evaluated a single surgeon's series of patients treated by multilevel cervical disc excision (two or three levels), allograft tricortical iliac crest arthrodesis, and anterior instrumentation. The objective of this retrospective study was to compare fusion success and clinical outcome between multilevel Smith-Robinson interbody grafting and tricortical iliac strut graft reconstruction, both supplemented with anterior instrumentation in the cervical spine. The incidence of nonunion for cervical discectomy and fusion varies widely depending on the number of disc levels involved, type of bone graft used, and whether the anterior grafting is supplemented with instrumentation. An alternative to multilevel interbody fusion is corpectomy and strut grafting, in which the incidence of nonunion has been reported to be 27% with autograft and 41% with allograft. Sixty-four consecutive patients who underwent allograft tricortical iliac crest reconstruction and anterior cervical plating were studied. The average follow-up was 39 months. There were 38 patients in the discectomy and interbody grafting group and 26 patients in the corpectomy and strut graft reconstruction group. Pseudoarthrosis occurred in 42% of the anterior cervical interbody fusion patients and 31% of the corpectomy patients. Nonunion in two-level interbody fusions occurred in 36% of the patients as compared to 10% for patients with one-level corpectomies; while 54% of patients with three-level interbody fusions and 44% of patients with two-level corpectomies were noted to have pseudoarthrosis. Higher percentages of nonunion were noted in multilevel interbody grafting than in corpectomy with strut grafting and when more vertebral levels were involved. These radiographic and clinical findings underscore the shortcomings of multilevel anterior cervical allograft reconstruction with plating. Corpectomy may be the preferred method when multiple disc levels are fused. In addition, anterior corpectomy affords decompression of significant osteophytes in a safer and quicker manner. In retrospective studies, there is a need for long-term follow-up before accurate statements can be made about the study population.

Rigid internal fixation with lateral mass plates in multilevel anterior and posterior reconstruction of the cervical spine

STUDY DESIGN

A retrospective clinical and radiographic analysis was performed on 17 patients with multilevel cervical disease who were treated with anterior and posterior reconstruction with a new rigid, segmental, internal fixation system applied to the lateral masses.

OBJECTIVES

To determine the applicability, safety, and clinical efficacy of an instrumentation system used as a cervical lateral mass plate in the management of complex spinal disorders.

SUMMARY OF BACKGROUND DATA

Cervical disorders involving three or more levels present a difficult reconstruction problem, especially if the posterior elements are deficient. Segmental fixation with lateral mass plating provides an alternative method to situations that would otherwise require a halo.

METHODS

Seventeen patients treated by a single surgeon underwent cervical reconstruction surgery involving three or more levels. All patients had anterior decompression and reconstruction and a posterior fusion with rigid internal fixation with a device applied to the lateral masses of the cervical vertebrae. Patients were reviewed clinically and radiographically to determine the efficacy and safety of this method of fixation.

RESULTS

Of the 15 patients with adequate follow-up data that were studied, the condition of 13 patients, (87%) was improved, that of one patient (6.7%) was the same, and that of another (6.7%) was worse after surgical intervention. Sagittal alignment was restored to within 5 degrees of the preoperative lordosis in active extension by the modified Cobb method and the Gore method. No patient had radiographic nonunion. One patient had a sensory radiculopathy associated with an overpenetrated lateral mass screw that partially resolved after hardware removal. One patient had asymptomatic loosening of a C7 lateral mass screw.

CONCLUSIONS

Segmental posterior fixation with lateral mass plating provides more rigid immobilization than traditional techniques, allows restoration and maintenance of spinal alignment, obviates the need for halo immobilization, and is associated with a low incidence of neurovascular injury.

Corpectomy for multi-level cervical spondylosis and ossification of the posterior longitudinal ligament

The choice of a surgical approach for multi-level cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) is still a controversial issue. While most of the surgeons are still performing decompression by laminectomy, some are doing multi-level anterior decompression. Few neurosurgeons are performing decompression by corpectomy. We have treated 26 patients by median cervical corpectomy during the last 4 years. These patients were followed up for a mean period of 25 months. Twenty one (80%) patients had a good outcome, 2 patients remained unchanged and 3 expired. Review of the literature and our experience indicates that patients with CSM and OPLL should be operated by median cervical corpectomy (anterior approach).

Cervical spondylotic myelopathy: surgical decision making

Cervical spondylotic myelopathy can produce a variety of clinical signs and symptoms secondary to neural compromise and biomechanical involvement of the spine. The surgical treatment of cervical spondylotic myelopathy remains a controversial issue after many years of study, evolution, and refinement. Several ventral, dorsal, or combined approaches have been defined. The complications associated with ventral approaches and the concerns about kyphosis following dorsal approaches led to the development of a variety of laminoplasty procedures. This paper reviews the biomechanical basis of cervical spondylotic myelopathy and its effect on choosing the appropriate surgical approach.

Spinal shortening in scoliosis surgery, A case with transitory paraplegia

STUDY DESIGN

A case involving a 16-year-old patient with idiopathic adolescent double-major scoliosis is presented. The curve was so rigid that a shortening surgery was done to reduce neurologic risk.

OBJECTIVE

To advise surgeons who are considering this kind of surgical procedure to reduce the neurologic risk involved in correcting scoliosis, may be more dangerous than other, more traditional modes. SUMMARY OF BACKGROUND DATE: The two-stage procedure for anterior resection of a vertebral body followed by posterior resection and fusion by shortening the spine with instrumentation has been reported to be a safe and effective method of correcting deformities and other spinal pathologies.

METHODS

Surgical treatment consisted of two anterior approaches, thoracic lumbotomy and thoracofrenolumbotomy, in which all the discs between 75 and L4 and the vertebral body of T8 were resected, followed by a posterior resection. In the third surgery (posterior resection) a full T8 vertebrectomy was completed, and the gap between the adjacent vertebrae was closed. Then a traditional CD configuration with rod rotation was used, and a thoracoplasty of the rib hump was done.

RESULTS

During the intraoperative wake-up test, the patient did not move her inferior extremities, and it was necessary to partially reverse the shortening of the gap produced by the vertebrectomy. The preoperative and postoperative curves measured 90 degrees/86 degrees and 25 degrees/27 degrees, respectively.

CONCLUSIONS

This procedure appears to be more dangerous than traditional surgery. Partial vertebrectomy as a closing wedge osteotomy of the convexity may be a less risky procedure. The practice of not using bone graft in the intervertebral spaces does not seem to contribute to spinal shortening and increases the pseudoartosis risk.

On the pathogenesis of the radiculopathy complicating multilevel corpectomy

Postoperative fifth cervical radiculopathy has been described after cervical corpectomy. One explanation for this complication is thought to be the factor of traction on cervical roots caused by a shifting of the spinal cord consequent to decompression. This theory is supported by our experience with 176 patients undergoing corpectomies for whom a lesser width of decompression all but eliminated the complication.

Anterior decompressive microsurgery and osteosynthesis for the treatment of multi-segmental cervical spondylosis. Pathophysiological considerations, surgical indication, results and complications: a survey

Surgical treatment of cervical myelopathy due to multi-segmental cervical spondylosis (MSCS) is currently performed by either anterior or posterior approaches. Considering the complex nature of the underlying disease involving more than one cervical segment, as well as the patho-biomechanical features of the spondylotic cervical spine, adequate decompression of the spinal cord and correction of hypermobility should be achieved by surgery in one stage, in order to achieve positive immediate and long-term benefit for the patient suffering from progressive myelopathy. Recently, anterior decompressive surgery, consisting of single or multi-level vertebrectomy, microsurgical epidural decompression and osteo-synthesis has emerged as an aggressive therapeutic approach for the treatment of MSCS. Based on the experience of a series of 92 patients with progressive cervical myelopathy due to MSCS operated on using the above described combined techniques, as well as the results from a limited number of clinical studies of anterior decompressive surgery in MSCS patients from the literature, the pathophysiological considerations, surgical indications, surgical technique as well as clinical results and complications of anterior surgery in patients with MSCS are reviewed and discussed.

Surgical treatment for cervical spondylitic myelopathy

The long-term outcome of cervical spondylitic myelopathy after surgical treatment was retrospectively reviewed and critically evaluated in 100 patients with documented cervical myelopathy treated between 1978 and 1988 at our institution. Eighty-four patients were available for long-term study. The median duration of follow up was 7.35 years (range 3 to 9.5 years). There were 67 men and 17 women; their ages ranged from 27 to 86 years. The duration of preoperative symptoms ranged from 1 month to 10 years. Preoperative functional grade as evaluated with the Nurick Scale for the group was 2.1. Thirty-three patients with primarily anterior cord compression, one- or two-level disease, or a kyphotic neck deformity were treated by anterior decompression and fusion. Fifty-one patients with primarily posterior or cord compression and multiple-level disease were treated by posterior laminectomy. There was no difference in the preoperative functional grade in these two groups. The patients in the posterior treatment group were older (59 vs 55 years). There was no surgical mortality from the operative procedures; morbidity was 3.6%. Of the 33 patients undergoing anterior decompression and fusion, 24 showed immediate functional improvement and nine were unchanged. Of the 51 patients who underwent posterior laminectomy, 35 demonstrated improvement, 11 were unchanged, and five were worse. Six patients, one in the anterior group and five in the posterior group, demonstrated early deterioration. Late deterioration occurred from 2 to 68 months postoperatively. Four (12%) patients who had undergone anterior procedures had additional posterior procedures, and seven (13.7%) patients who had undergone posterior procedures had additional decompressive surgery. The final functional status at last follow-up examination for the 33 patients in the anterior group was improved in 18, unchanged in nine, and deteriorated in six. Of the 51 patients who underwent posterior decompression, 19 benefited from the surgery, 13 were unchanged, and 19 were worse at last follow up than before their initial surgical procedure. Age, severity of disease, number of levels operated, and preoperative grade were not predictive of outcome. The only factor related to potential deterioration was the duration of symptoms preoperatively. The results indicate that with anterior or posterior decompression, long-term outcome is variable, and a subgroup of patients, even after adequate decompression and initial improvement, will have late functional deterioration.

Marie François Xavier Bichat (1771-1802)

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Management of cervical spondylotic myelopathy and radiculopathy

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Oblique transcorporeal approach to anteriorly located lesions in the cervical spinal canal

The technique of obliquely drilling out the postero-lateral part of the cervical vertebral bodies is described. It uses the antero-lateral (retro carotico-jugular) approach to control and displace the vertebral artery postero-laterally and to expose the lateral aspect of the vertebral bodies. It provides, through a wide field and with minimal retraction of the carotid artery and the internal jugular vein, an extensive view of the anterior aspect of the spinal cord. It has already been used to treat 15 anterior lesions compressing the spinal cord including neurinomas and osteophytes.

Spondylectomy, microsurgical decompression and osteosynthesis in the treatment of complex disorders of the cervical spine

In 44 patients with complex degenerative, traumatic, neoplastic and infectious disorders of the cervical spine an aggressive surgical approach was used, consisting of spondylectomy, radical microsurgical decompression and osteosynthesis. The patient group consisted of 23 patients with multisegmental cervical spondylosis, 9 patients with primary or metastatic malignant tumour disease spread along the cervical spine, 6 patients with complex cervical trauma and 6 patients with infection affecting one or more cervical segments. Considering the heterogeneity of the group of patients treated, a multitude of neurological symptoms and signs were present. Excruciating pain was the predominant symptom in 84% of the patients, followed by sensory and motor signs of varying degrees in 77% and 65% respectively. Involvement of the long tracts was present in 51%, gait disturbance in 49% and bladder disfunction in 28%. Considering the nature of the underlying disease, in the group with multisegmental cervical spondylosis (MSCS), advanced cervical myelopathy was the predominant clinical symptom, whereas in those patients with trauma, tumour or infection, pain was the leading symptom, followed by disturbed motor and/or sensory function. Altogether 59 vertebrae have been removed in the 44 patients. In 28 patients spondylectomy was performed at one level, in 15 patients at two levels and in one female tumour patient at three levels. In 34 patients an iliac crest bone graft was used and in 10 patients bone cement. Within the observation period, solid fusion was achieved in all patients. In one tumour patient screw loosening was demonstrable at follow-up, but the fusion remained stable. 2 patients with infectious disease required re-operation due to significant loosening of screws and plates. However, after re-stabilization solid fusion was achieved. Considering amelioration of specific pre-operative symptoms and signs, excruciating pain responded best to the stabilizing procedure, with improvement in over 90% of the patients, followed by improvement of sensory and motor deficits in 85% and 82% respectively. Improvement in pre-operative gait disturbance could be achieved in 81% of the patients, while disturbance of bladder function is less likely to improve after surgery with a positive response in only 58%. None of the patients became neurologically worse after surgery. With regard to the underlying disease, patients with MSCS and tumour had the best results with overall improvement in 62% and 75% respectively. While in patients with infection improvement could be achieved in 58%, improvement in trauma patients was demonstrable in only 34% while in 66% the pre-operative clinical status remained unchanged.(ABSTRACT TRUNCATED AT 400 WORDS)