Microsurgical treatment of lumbar disc herniation: follow-up of 237 patients

Validation of a surgical drill with a haptic interface in spine surgery

Real haptics is a technology that reproduces the sense of force and touch by transmitting contact information with real objects by converting human movements and the feel of the objects into data. In recent years, real haptics technology has been installed in several surgical devices. A custom-made surgical drill was used to drill into the posterior lamina to verify the time required for penetration detection and the distance the drill advanced after penetration. A surgeon operated with the drill and the same aspects were measured and verified. All experiments were performed on female miniature pigs at 9 months of age with a mean body weight of 23.6 kg (range 9-10 months and 22.5-25.8 kg, n = 12). There were statistically significant differences in the average reaction time and the distance travelled after penetration between a handheld drill and the drill with the penetration detection function (p < 0.001). The reaction time to detect penetration and the distance after penetration were both significantly improved when compared with those of the handheld surgical drill without the penetration detection function, with mean differences of 0.049 ± 0.019 s [95% CI 0.012, 0.086 s] and 2.511 ± 0.537 mm [95% CI 1.505, 3.516 mm]. In this study, we successfully conducted a performance evaluation test of a custom-made haptic interface surgical drill. A prototype high-speed drill with a haptic interface accurately detected the penetration of the porcine posterior lamina.

Return to work after lumbar disc herniation surgery: an occupational cohort study

Background and purpose - Lumbar disc herniation is a common surgically treated condition in the working-age population. We assessed health-related risk factors for return to work (RTW) after excision of lumbar disc herniation. Previous studies on the subject have had partly contradictory findings.Patients and methods - RTW of 389 (n = 111 male, n = 278 female; mean age 46 years, SD 8.9) employees who underwent excision of lumbar disc herniation was assessed based on the Finnish Public Sector Study (FPS). Baseline information on occupation, preceding health, and health-risk behaviors was derived from linkage to national health registers and FPS surveys before the operation. The likelihood of RTW was analyzed using Cox proportional hazard univariable and multivariable modelling.Results - 95% of the patients had returned to work at 12 months after surgery, after on average 78 days of sickness absence. Faster RTW in the univariable Cox model was associated with a small number of sick leave days (< 30 days) before operation (HR 1.3, 95% CI 1.1-1.6); high occupational position (HR 1.6, CI 1.2-2.1); and age under 40 years (HR 1.5, CI 1.1-1.9). RTW was not associated with sex or the health-related risk factors obesity, physical inactivity, smoking, heavy alcohol consumption, poor self-rated health, psychological distress, comorbid conditions, or purchases of pain or antidepressant medications in either the univariable or multivariable model.Interpretation - Almost all employees returned to work after excision of lumbar disc herniation. Older age, manual job, and prolonged sick leave before the excision of lumbar disc herniation were risk factors for delayed return to work after the surgery.

Decreasing Incidence of Lumbar Discectomy Surgery in Finland in 1997-2018

STUDY DESIGN

Retrospective register study.

OBJECTIVE

The aim of this study was to assess the incidence and trends of lumbar disc surgeries in Finland from 1997 through 2018.

SUMMARY OF BACKGROUND DATA

The evidence on lumbar spine discectomy has shifted from supporting surgical treatment toward nonoperative treatment. Still, the incidence of lumbar discectomy operations increased until the 1990 s. In the United States, the incidence began to decline after a downward turn in 2008, yet recent trends from countries with public and practically free health care are not widely known.

METHODS

Data for this study were obtained from the Finnish nationwide National Hospital Discharge Register. The study population covered all patients 18 years of age or older in Finland during a 22-year period from January 1, 1997, to December 31, 2018.

RESULTS

A total of 65,912 lumbar discectomy operations were performed in Finland from 1997 through 2018. The annual population-based incidence of lumbar discectomy decreased 29% during the 22-year period, from 83 per 100,000 person-years in 1997 to 58 per 100,000 person-years in 2018. In addition, the incidence of microdiscectomy increased 12%, from 41 per 100,000 person-years in 1997 to 47 per 100,000 person-years in 2018, whereas the incidence of open discectomy decreased 71%, from 41 per 100,000 person-years in 1997 to 12 per 100,000 person-years in 2018. The total reoperation rate for microendoscopic, microscopic, and open discectomy surgeries was 16.3%, 15.3%, and 14.9%, respectively.

CONCLUSION

The nationwide incidence of lumbar discectomy decreased in Finland from 1997 through 2018. Additionally, the incidence of open discectomy is decreasing rapidly, whereas the incidence of microsurgical techniques is increasing.Level of Evidence: 3.

Back pain is also improved by lumbar disc herniation surgery

Background and purpose - Indication for lumbar disc herniation (LDH) surgery is usually to relieve sciatica. We evaluated whether back pain also decreases after LDH surgery.Patients and methods - In the Swedish register for spinal surgery (SweSpine) we identified 14,097 patients aged 20-64 years, with pre- and postoperative data, who in 2000-2016 had LDH surgery. We calculated 1-year improvement on numeric rating scale (rating 0-10) in back pain (N_back) and leg pain (N_leg) and by negative binomial regression relative risk (RR) for gaining improvement exceeding minimum clinically important difference (MCID).Results - N_leg was preoperatively (mean [SD]) 6.7 (2.5) and N_back was 4.7 (2.9) (p < 0.001). Surgery reduced N_leg by mean 4.5 (95% CI 4.5-4.6) and N_back by 2.2 (CI 2.1-2.2). Mean reduction in N_leg) was 67% and in N_back 47% (p < 0.001). Among patients with preoperative pain ≥ MCID (that is, patients with significant baseline pain and with a theoretical possibility to improve above MCID), the proportion who reached improvement ≥ MCID was 79% in N_leg and 60% in N_back. RR for gaining improvement ≥ MCID in smokers compared with non-smokers was for N_leg 0.9 (CI 0.8-0.9) and -N_back 0.9 (CI 0.8-0.9), and in patients with preoperative duration of back pain 0-3 months compared with > 24 months for N_leg 1.3 (CI 1.2-1.5) and for N_back 1.4 (CI 1.2-1.5).Interpretation - LDH surgery improves leg pain more than back pain; nevertheless, 60% of the patients with significant back pain improved ≥ MCID. Smoking and long duration of pain is associated with inferior recovery in both N_leg and N_back.

Radiopaque Gelified Ethanol Application in Lumbar Intervertebral Soft Disc Herniations: Croatian Multicentric Study

Objective

Minimally invasive percutaneous spinal procedures are popular in trying to reduce spinal pain. The aim of this paper is to evaluate the safety of intervertebral disc chemonucleolysis and to report the effectiveness of a percutaneous, minimally invasive treatment for contained herniated intervertebral discs in the lumbar spine using the recently marketed radiopaque gelified ethanol.

Methods

Pain relief before and after the procedure was self-evaluated by each patient using a verbal numeric scale (VNS) ranging from 0 to 10. Patients were also scored prior to procedure and after chemonucleolysis during several follow-up periods using the Roland-Morris low back pain and disability questionnaire (RMQ). Follow-up periods were defined as 0-6, 6-12, 12-18, 18-24, and 24-30 months. Clinically significant functional improvement (CSFI) was defined as a decrease of five or more points on the RMQ scale and a decrease of at least 50% of pain intensity using VNS.

Results

Using the RMQ scale, CSFI was achieved in 20/29 patients in the first follow-up period, 20/27 patients in the second follow-up period, 9/12 patients in the third follow-up period, 8/9 patients in the fourth follow-up period, and 4/4 patients in the last follow-up period. Using the VNS rating, CSFI was accomplished in 19/29 patients in the first follow-up period, 19/27 patients in the second follow-up period, 9/12 patients in the third follow-up period, 8/9 patients in the fourth follow-up period, and 4/4 in the last follow-up period.

Conclusions

Intradiscal application of gelified ethanol may be effective in pain reduction using the VNS and Roland-Morris low back pain and disability questionnaire. The treatment is safe and easy to handle.

Cerebrospinal fluid leaks after spine tumor resection: avoidance, recognition and management

Post-operative CSF leaks are a known complication of spine surgery in general, and patients undergoing surgical intervention for spinal tumors may be particularly predisposed due to the presence of intradural tumor and a number of other factors. Post-operative CSF leaks increase morbidity, lengthen hospital stays, prolong immobilization and subject patients to a number of associated complications. Intraoperative identification of unintended durotomies and effective primary repair of dural defects is an important first step in the prevention of post-operative CSF leaks, but in patients who develop post-operative pseudomeningoceles, durocutaneous fistulae or other CSF-leak-related sequelae, early recognition and secondary intervention are paramount to preventing further CSF-leak-related complications and achieving the best patient outcomes possible. In this article, the incidence, risk factors and complications of CSF leaks after spine tumor surgery are reviewed, with an emphasis on avoidance of post-operative CSF leaks, early post-operative identification and effective secondary intervention.

Long-Term Results of Various Operations for Lumbar Disc Herniation: Analysis of over 39,000 Patients

OBJECTIVE

To determine the long-term follow-up of the various operations for lumbar disc herniation in a large patient population.

SUBJECTS AND METHODS

Patients who had operations for lumbar disc herniation (microdiscectomy, endoscopic microdiscectomy and the 'classical operation', i.e. laminectomy/laminotomy with discectomy) were collected from the world literature. Patients who had follow-ups for at least 2 years were analyzed relative to the outcome. The outcome was graded by the patients themselves, and the operative groups were compared to one another.

RESULTS

39,048 patients collected from the world literature had had lumbar disc operations for disc herniations. The mean follow-up period was 6.1 years, and 30,809 (78.9%) patients reported good/excellent results. Microdiscectomy was performed on 3,400 (8.7%) patients. The mean follow-up was 4.1 years with 2,866 (84.3%) good/excellent results, while 1,101 (3.6%) patients had endoscopic microdiscectomy. There, the mean follow-up was 2.9 years with 845 (79.5%) good/excellent results. The classical operation was performed on 34,547 (88.5%) patients with a mean follow-up period of 6.3 years, and 27,050 (78.3%) patients had good/excellent results. These results mirror those with discectomy and the placement of prosthetic discs.

CONCLUSIONS

The analysis of 39,048 patients with various operations for lumbar disc herniation revealed the same pattern of long-term results. Patients who had microdiscectomy, endoscopic microdiscectomy or the classical operation (laminectomy/laminotomy with discectomy) all had approximately 79% good/excellent results. None of the operative procedures gave a different outcome. l.

Private and Non-Private Disc Herniation Patients: Do they Differ?

Objectives :

In the 2006 yearly report from the Swedish National Register for Lumbar Spine Surgery it was claimed that international studies show obvious differences between private and non-private patients with regard to results from back surgery. Therefore our aim was to reveal such possible differences by comparing the two categories of patients at a private clinic.

Material and Methods :

The material comprises 1184 patients operated on for lumbar disc herniation during the period of 1987 to 2007. Basic pre-operative data were obtained from the medical records and follow-up was performed by a questionnaire around 5 years post-operatively.

Results :

Small but statistically significant differences between private and non-private patients were seen pre-operatively regarding the proportions of a/ men and women in the samples, b/ those with physically demanding jobs, c/ those on sick leave and d/ those with lumbar pain. Over the years the admitted private patients had a decreasing mean duration of symptoms which was not seen in the non-private patients. No apparent differences (n.s.) were seen between the two categories of patients pre-operatively regarding age, presence and level of leg pain or the proportion who smoked. Post-operative improvement in leg and lumbar pain was very similar in private and non-private patients as was satisfaction with the results and the proportion of patients returning to work.

Conclusion :

Despite small pre-operative differences concerning some variables and a significant difference in symptom duration between private and non-private disc herniation patients, the final clinical results were very similar.

Primary limited lumbar discectomy with an annulus closure device: one-year clinical and radiographic results from a prospective, multi-center study

Objective

Discectomy as a treatment for herniated lumbar discs results in outcomes after surgery that are not uniformly positive. Surgeons face the dilemma between limited nucleus removal which is associated with a higher risk of recurrence, or more aggressive nucleus removal which may lead to disc height loss and persistent back-pain. annulus closure devices may allow for the benefits of limited nucleus removal without the increased risk of recurrence. This is an interim report of an ongoing 24-month post-marketing study of the Barricaid® annulus closure device, consisting of a flexible polymer mesh that blocks the defect, held in place by a titanium bone anchor.

Methods

We prospectively enrolled 45 patients at four hospitals, and implanted the Barricaid® after a limited discectomy. annulus defect size and volume of removed nucleus were recorded. Reherniations were reported, pain and function were monitored and imaging was performed at regular intervals during 24 months of follow-up.

Results

At 12 months postsurgery, pain and function were significantly improved, comparing favorably to reported results from limited discectomy. Disc height has been well maintained. One reherniation has occurred (2.4%), which was associated with a misplaced device. No device fracture, subsidence or migration has been observed.

Conclusion

The use of an annulus closure device may provide a reduction in reherniation rate for lumbar discectomy patients with large annulus defects who are at the greatest risk of recurrence. Using such a device should provide the surgeon increased confidence in minimizing nucleus removal, which, in turn, may preserve disc height and biomechanics, reducing degeneration and associated poor clinical outcomes in the long-term. A randomized multicenter study evaluating limited discectomy with and without the Barricaid® is currently underway, and will provide a higher level of evidence.

[Learning curve for lumbar disc surgery]

BACKGROUND AND PURPOSE

Various techniques are available for lumbar disc surgery. But failure and severe adverse events still occur during such procedures. Recent work concluded that the use of microscope was not mandatory for such procedures.

METHODS

The first 70 spinal procedures for lower limb radicular syndrome by a surgeon at the beginning of this activity where studied. Particular interest was paid on adverse events, especially complications and failures.

RESULT

Average duration of surgery (50min) and rate of reoperation (six reoperations needed out of 65 patients, five of them by the same surgeon) where, as expected, a bit higher than published in experienced hands. But no battered-root syndrome, injury to neighboring structures or other severe complication was observed. Noteworthy is that no patient was neurologically worsened by surgery.

CONCLUSIONS

If the use of microscope may not be needed for lumbar disc open surgery in experienced hands, we strongly advice surgeons at the beginning of their practice to use it. At least, to avoid unforgiving mistakes such as picking out the root instead of the herniation.

Incidental durotomy during spine surgery: incidence, management and complications. A retrospective review

STUDY DESIGN

Retrospective review of a series of patients who underwent spinal surgery at a single spine unit during a 1 year period.

OBJECTIVES

To assess the incidence, treatment, clinical consequence, complications of incidental durotomy during spine surgery and results of 37 months clinical follow-up.

SUMMARY OF BACKGROUND DATA

Incidental durotomy is an underestimated and relatively adverse event during spinal surgery. Several consequences of inadequately treated dural tears have been reported.

METHODS

A retrospective review was conducted on 1326 consecutive patients who underwent spinal surgery performed in one French spine unit from January 2005 to December 2005. We excluded from this study patients treated for emergency spine cases.

RESULTS

Fifty-one dural tears were identified (3.84%). Incidental durotomies were associated with anterior cervical approach in 1 case, with posterior cervical approach in 1 case, with anterior retroperitoneal approach in 1 case and with posterior thoracolumbar approach in 48 cases. In addition, any clinically significant durotomy unrecognised during surgical procedure were included. Thirteen patients presented postoperative complications including 7 cerebrospinal fluid leaks, 2 wound infections, 2 postoperative haematomas, and 2 pseudomeningoceles. Nine of these 13 patients required a revision procedure. A mean follow-up of 37 months showed good long-term clinical results.

CONCLUSIONS

Incidental durotomy is a common complication of spine surgery. All incidental durotomies must be repaired primarily. Dural tears that were immediately recognised and treated accordingly did not lead to any significant sequelae at a mean follow-up of 37 months. However, long-term follow-up studies will be needed to confirm this finding. The risks associated with dural tears and cerebrospinal fluid leaks are serious and should be discussed with any patients undergoing spine surgery.

Long-term outcome after microendoscopic diskectomy for lumbar disk herniation: a prospective clinical study with a 5-year follow-up

BACKGROUND

Several authors have reported results obtained with the microendoscopic diskectomy (MED) technique, but the long-term outcome has not been described. This report summarizes our clinical experience with the lumbar MED technique with a long-term follow-up period.

OBJECTIVE

To evaluate the efficacy of the MED for lumbar disk herniation and to report long-term outcome and complications (5-year follow-up).

METHODS

One hundred twenty consecutive patients with lumbar disk herniation were treated with the METRx system.We included all types of lumbar herniated disks: contained, not contained, foraminal, and migrated disk herniations. The results were evaluated with the Visual Analog Scale (VAS) pain score, Oswestry Disability Index score, patient satisfaction questionnaire, and modified Macnab criteria.

RESULTS

The average age of patients was 41 years; 65 were men and 55 were women. The most commonly affected level was L5-S1 (54.2%). The follow-up time after surgery was 5 years in all cases. We obtained good or excellent results in 75% of patients and regular results in 18%. Good subjective satisfaction was observed with surgery in 92% of patients. The mean decrease in the Oswestry Disability Index score was 52.8 ± 21.6; the mean decrease in leg VAS score was 6.1 ± 2.3; and the mean decrease in lumbar VAS score was 1.9 ± 3.3. Adjusted mean differences were statistically significant in all cases (P < .05).

CONCLUSION

MED not only reduces the incision, tissue damage, and postoperative period of incapacity but also offers long-term results comparable to those of conventional techniques.

Clinical outcomes after posterior dynamic transpedicular stabilization with limited lumbar discectomy: Carragee classification system for lumbar disc herniations

BACKGROUND

The observed rate of recurrent disc herniation after limited posterior lumbar discectomy is highest in patients with posterior wide annular defects, according to the Carragee classification of type II (fragment-defect) disc hernia. Although the recurrent herniation rate is lower in both type III (fragment-contained) and type IV (no fragment-contained) patients, recurrent persistent sciatica is observed in both groups. A higher rate of recurrent disc herniation and sciatica was observed in all 3 groups in comparison to patients with type I (fragment-fissure) disc hernia.

METHODS

In total, 40 single-level lumbar disc herniation cases were treated with limited posterior lumbar microdiscectomy and posterior dynamic stabilization. The mean follow-up period was 32.75 months. Cases were selected after preoperative magnetic resonance imaging and intraoperative observation. We used the Carragee classification system in this study and excluded Carragee type I (fragment-fissure) disc herniations. Clinical results were evaluated with visual analog scale scores and Oswestry scores. Patients' reherniation rates and clinical results were evaluated and recorded at 3, 12, and 24 months postoperatively.

RESULTS

The most common herniation type in our study was type III (fragment-contained), with 45% frequency. The frequency of fragment-defects was 25%, and the frequency of no fragment-contained defects was 30%. The perioperative complications observed were as follows: 1 patient had bladder retention that required catheterization, 1 patient had a superficial wound infection, and 1 patient had a malpositioned transpedicular screw. The malpositioned screw was corrected with a second operation, performed 1 month after the first. Recurrent disc herniation was not observed during the follow-up period.

CONCLUSIONS

We observed that performing discectomy with posterior dynamic stabilization decreased the risk of recurrent disc herniations in Carragee type II, III, and IV groups, which had increased reherniation and persistent/continuous sciatica after limited lumbar microdiscectomy. Moreover, after 2 years' follow-up, we obtained improved clinical results.

Epidural steroid following discectomy for herniated lumbar disc reduces neurological impairment and enhances recovery: a randomized study with two-year follow-up

STUDY DESIGN

We randomized 200 patients after lumbar discectomy to receive epidural steroid or none with a 2-year follow-up.

OBJECTIVE

To evaluate the outcome, neurologic impairment and safety of epidural steroid following lumbar discectomy for herniated disc disease.

SUMMARY OF BACKGROUND DATA

Convalescence after discectomy for herniated disc disease is dependent on pain and the inflammatory response. Previous studies in arthroscopic and abdominal surgery demonstrate steroids, which reduce the inflammatory response and enhance recovery. Here we report a 2-year follow-up of a randomized trial of epidural steroid following lumbar discectomy.

METHODS

Through 2001 and 2003 200 patients undergoing discectomy for herniated disc disease were randomly allocated to receive epidural methylprednisolone 40 mg or none. In the control group (62 males and 38 females, median age 41 years, 18-66) 48 L5, 50 L4, and 6 L3 discectomies were performed and in the intervention group (60 males and 40 females, median age 45 years, 15-53) 56 L5, 46 L4, and 3 L3 discectomies. Contemporary with randomization to epidural steroid or none both groups received preoperative prophylactic antibiotics and the same multimodal pain treatment.

RESULTS

Hospital stay was reduced from 8 to 6 days (P = 0.0001) and the number of patients with neurologic signs were reduced more (70% vs. 44%, P = 0.0004) by epidural steroid. Incidence of reoperation at 1 year was 6% in both groups and 8% in the control group and 7% in the intervention group after 2 years. No infections were registered.

CONCLUSION

Epidural methylprednisolone enhances recovery after discectomy for herniated disc disease without apparent side effects.

Risk factors for back pain-related loss of working time after surgery for lumbar disc herniation: a 5-year follow-up study

The aim of this study is to explore the occurrence and the risk factors of back-related loss of working time in patients undergoing surgery for lumbar disc herniation. One hundred and fifty-two gainfully employed patients underwent surgery for lumbar disc herniation. Two months postoperatively, those patients completed a self-report questionnaire including queries on back and leg pain (VAS), functional capacity (Oswestry disability index--ODI, version 1.0), and motivation to work. After 5 years, lost working time was evaluated by means of a postal questionnaire about sick leave and disability pensions. The cumulative number of back pain-related days-off work was calculated for each patient. All 152 patients, 86 men and 66 women, were prescribed sick leave for the first 2 months. Thereafter, 80 (53%) of them reported back pain-related sick leave or early retirement. A permanent work disability pension due to back problems was awarded to 15 (10%) patients, 5 men (6%) and 10 women (15%). Median number of all work disability days per year was 11 (interquartile range [IQR] 9-37); it was 9 days (IQR 9-22) in patients with minimal disability (ODI score 0-20) at 2 months postoperatively and 67 days (IQR 9-352) in those with moderate or severe disability (ODI > 20; P < 0.001). The respective means were 61, 29, and 140 days/year. Multivariate analysis showed ODI > 20, leg pain, and poor motivation to work to be the risk factors for extension of work disability. Results of the present study show that after the lumbar disc surgery, poor outcome in questionnaire measures the physical functioning (ODI) and leg pain at 2 months postoperatively, as well as poor motivation to work, are associated with the loss of working time. Patients with unfavourable prognosis should be directed to rehabilitation before the loss of employment.

20 years follow-up after the first microsurgical lumbar discectomies in Iceland

BACKGROUND

Microsurgical discectomies are an established procedure in spinal surgery. This operating technique was first used in the Department of Neurosurgery in Iceland in 1981 and has become standard operative treatment for herniated lumbar discs. There is a great variability in outcome reports regarding recurrence rate and re-operation rate. Few articles are based on follow-up of more than 10 years. This article presents the results of a 20 years follow-up study.

METHODS

A retrospective study of all patients undergoing microsurgical discectomy for herniated lumbar disc, from June 1, 1981 to December 31, 1984. Outcome, based on recurrence rate, return to work and patient satisfaction was determined by a self-evaluation questionnaire, phone interviews and patient medical records.

FINDINGS

Of the 170 patients, 134 (78.8%) were included in the study (M:F, 58:42%). Preoperative symptoms: back pain with sciatica 108 (80.6%), sciatica 20 (14.9%), back pain 2 (1.5%). Mean follow-up time was 20.7 years (19.5-22.8). Recurrence rate was 12.7%. 19 patients (14.2%) underwent a subsequent lumbar operation at a different level or side. A majority of patients 108 (80.6%) returned to previous level of work, 26 (19.4%) lost some or all working capabilities. Patient satisfaction was high, 91.1% reporting excellent (68.7%) or good (22.4%) results. 5.2% of patients rated the outcome fair and 3.7% poor. Women reported worse outcome than men, excellent M:F 74.7:60.7%, and poor 7.1:1.3%. There was no significant difference in patient satisfaction in patients undergoing additional operations or those with recurrence of the herniated disc.

CONCLUSIONS

Outcome was very good with 92.0% return to work and 91.1% patient satisfaction. The recurrence rate was 12.7% with a substantial number of cases occurring 10-20 years after operation. To conclude, microsurgical discectomies maintain a high success rate in the long-term.

Medial facetectomy in recurrent lumbar nerve root compression

This study investigated the outcome of medial facetectomy in reoperations after a previous discectomy. In a consecutive series of 98 patients with varying combinations of disc herniation, lateral stenosis, and scar, a good or moderate outcome was reached in 57% of the patients. Scar as an operative finding was a significant factor for poor outcome, especially in patients with preoperative symptoms for >1 year.

Wrong disc space level surgery: medicolegal implications

BACKGROUND

Operating the wrong disc level for herniated disc disease is a rarely reported complication. However, it is considered by many a breach in the standard of care. It is not unusual for litigation to result. Sixty-nine cases of wrong disc space level surgery were identified; 68 cases were the subject of lawsuits.

METHODS

Sixty-five lawsuit outcomes were published in a national monthly newsletter of malpractice cases, Medical Malpractice Verdicts, Settlements and Experts. Two cases came from medicolegal review, one case from a news article, and one case for which no claim was made.

RESULTS

Thirty-seven cases were settled. A plaintiff verdict was rendered in 18 cases and a defense verdict in 13 cases (42% of the cases that were decided by a jury).

CONCLUSIONS

The authors summarize steps to reduce the incidence of this misadventure. The authors recommend that the patient be advised of this potential and the patient be informed of the risk factors when special circumstances exist.

Lumbar microdiscectomy: a historical perspective and current technical considerations

A historical review is presented of the original descriptions of lumbar discectomy, focusing on the evolution toward a less invasive surgical approach following the introduction of the operating microscope. From the initial work in Europe by Yaşargil and Caspar to the popularization of microdiscectomy by Williams and Wilson in the United States, this procedure has successfully reduced operative time, surgical morbidity, and incision size while allowing patients to return to work faster. Emphasis is placed on the importance of a careful preoperative clinical and radiographic evaluation by identifying factors that may help in the prediction of a successful surgical outcome. A modification of the lumbar microdiscectomy technique is described including patient positioning in the lateral position as well as minimal disc space and nerve root manipulation. In their experience performing more than 3000 microdiscectomies, the authors have produced good-to-excellent clinical results in nearly 90% of patients, with the majority returning to work within 1 month. The complication rate of dural tears, discitis, or root injury has been less than 2%, with a reoperation rate of 5%. The authors believe that lumbar microdiscectomy remains the gold standard with which all other discectomy techniques must be compared.

Long-term outcome of 104 patients after lumbar sequestrectomy according to Williams

OBJECTIVE

The authors report the late outcome of 104 consecutive patients after Williams' sequestrectomy for virgin lumbar disc herniation.

METHODS

The clinical records and the mailed questionnaires of 38 women and 66 men operated consecutively between March 1991 and November 1993 were analyzed retrospectively. In these 104 patients, 105 Williams' sequestrectomies were performed.

RESULTS

The mean age at operation was 50.5 years (range, 23.2-86.7 yr), and follow-up ranged from 4.1 to 6.9 years (mean, 5.3 yr). Success rates, including excellent, good, and fair results, were 92.5%, 94.7%, and 93.3% for lumbalgia, radicular pain, and neurological dysfunction, respectively. Only a few patients did not improve or presented with worsened symptoms. Three of four patients with cauda equina syndrome recovered immediately after the intervention. There were eight (7.7%) minor postoperative complications, which were treated conservatively. Three women and three men (5.8%) underwent a revision procedure for a recurrent lumbar disc herniation at the same level after 0.4 to 3.1 years (mean, 1.8 yr). Two (1.9%) of these patients underwent further operations because of reherniation, and they required internal instrumentation eventually because of failed back surgery syndrome.

CONCLUSION

Williams' conservative approach with sequestrectomy alone is a safe operative modality. It should be used whenever possible. As demonstrated in our series with a long follow-up time, the results are as favorable as or better than results after standard microsurgical lumbar discectomy with curettement of the interspace. Whether the incidence of failed back surgery syndrome can be reduced by this approach remains to be proved.

Unrecognized durotomy after lumbar discectomy: a report of four cases associated with the use of ADCON-L

STUDY DESIGN

This report describes four cases of symptomatic cerebral spinal fluid leak after lumbar microdiscectomy where ADCON-L was used.

OBJECTIVES

To report that ADCON-L may exacerbate cerebral spinal fluid leak from unrecognized, small dural tears after lumbar discectomy.

SUMMARY OF BACKGROUND DATA

ADCON-L is a porcine-derived polyglycan that is used with increasing frequency in spinal surgery. It is advocated to reduce postoperative peridural fibrosis and adhesions.

METHODS

Four cases of symptomatic cerebral spinal fluid leak after lumbar microdiscectomy were identified. Information on these patients was obtained by chart review.

RESULTS

Three patients had small, inadvertent durotomies that were not appreciated at surgery even with the aid of a microscope. The dural violation in the fourth patient occurred at the previous epidural steroid injection site located on the contralateral side of the laminotomy.

CONCLUSION

ADCON-L may inhibit dural healing and exacerbate cerebral spinal fluid leak from microscopic durotomies not recognized at the time of surgery.

Spondylodiscitis after lumbar discectomy. Incidence and a proposal for prophylaxis

STUDY DESIGN

An analysis of the incidence of spondylodiscitis after lumbar disc surgery in 1642 patients. In 508 patients no prophylactic antibiotics were given. In 1134 patients a collagenous sponge containing gentamicin was placed in the cleared disc space.

OBJECTIVES

To report the incidence of postoperative spondylodiscitis in cases in which no antibiotic prophylaxis was used, and to define the value of a collagenous sponge containing gentamicin in preventing disc space infections.

SUMMARY OF BACKGROUND DATA

Spondylodiscitis is considered to be a rare complication of lumbar disc surgery. The retrospective design of most studies and the rare use of magnetic resonance imaging for early radiologic diagnosis suggest that the reported incidence rates may be underestimates. Postoperative spondylodiscitis is the result of intraoperative contamination and, theoretically, could be prevented by treating these patients with prophylactic antibiotics.

METHODS

In 1642 patients, 1712 discectomies were performed. In 508 of these patients no prophylactic antibiotics were given; in 1134 of these patients a collagenous sponge containing gentamicin was placed in the cleared disc space. Clinical reexamination and, in cases of unsatisfactory results, laboratory and radiologic investigations were performed 4-8 weeks after surgery.

RESULTS

In nineteen of the 508 patients who were not treated with antibiotic prophylaxis (3.7%) a postoperative spondylodiscitis developed, whereas none of the 1134 patients who received antibiotic prophylaxis became symptomatic (P < 0.00001).

CONCLUSION

In the current study, a 3.7% incidence of postoperative spondylodiscitis was found in the absence of prophylactic antibiotics. Gentamicin-containing collagenous sponges placed in the cleared disc space were effective in preventing postoperative spondylodiscitis.

Fragment excision versus conventional disc removal in the microsurgical treatment of herniated lumbar disc

100 patients who had a lumbar microdiscectomy were retrospectively compared with 100 microsurgically treated patients who had only a removal of the herniated disc fragment. We were able to show that there are less "reherniations" in the fragment removal group and the clinical outcome is often better regarding postoperative problems of instability.

The C-reactive protein for detection of early infections after lumbar microdiscectomy

The tendency for short hospitalization after lumbar microdiscectomy implies the need for early confirmation or disapproval of serious postoperative infections such as spondylodiscitis or deep wound infections. The C-reactive protein (CRP) is a well-known screening parameter for monitoring postoperative infectious complications in other fields. Our objective was to establish the diagnostic significance of CRP-in comparison with ESR and WBC-for monitoring infectious complications after lumbar microdiscectomy. Over a 15 months period we studied prospectively a homogeneous group of N = 400 patients with lumbar disc herniations who were operated on a single level for the first time. CRP, ESR and WBC values were determined in all patients pre-operatively, and on postoperative days 1 and 5. Clinical and laboratory findings were correlated and the diagnostic significance of CRP, ESR and WBC calculated. N = 385 (96%) patients had an uneventful postoperative course. N = 15 (4%) patients developed infectious complications, of which N = 6 (1.5%) were unrelated and N = 9 (2.5%) related to surgery. Evaluation of the laboratory values showed: The CRP baseline is a very individual value of no prognostic relevance. A high postaggression peak is typical and essential as a reference value for only the future time course will disclose any infection. We found 0% false negative and 4% false positive results on day 5. The sensitivity for serial CRP testing was calculated as 100% and specificity as 95.8%. ESR (sensitivity: 78.1%/specificity: 38.1%) and WBC (sensitivity: 21.4%/specificity: 76.8%) both failed to reach such distinct diagnostic significance on day 5. The C-reactive protein has thus proved to be a reliable, simple and economical screening test for infectious complications after lumbar microdiscectomy, superior to classical laboratory parameters.

Cross-sectional areas of lumbar muscles after surgical treatment of lumbar disc herniation. A study with magnetic resonance imaging after microdiscectomy or percutaneous nucleotomy

We assessed in this study the potential development of postoperative muscle atrophy in the operation area in 39 patients treated by either microdiscectomy or percutaneous nucleotomy for lumbar disc herniation. The cross-sectional areas of the lumbar muscles were measured on magnetic resonance images created on the day preceding the operation and 6 months postoperatively. The cross-sections of the lumbar muscles remained unchanged during the observation period in all treated patients indicating that no muscle atrophy had developed in the operation area. Since peroperative tissue trauma may correlate with subsequent muscle denervation and atrophy, this finding may be due to the tissue sparing nature of microdiscectomy and percutaneous nucleotomy, thus encouraging the use of these techniques in the treatment of lumbar disc herniation.

Magnetic resonance image changes and clinical outcome after microdiscectomy or nucleotomy for ruptured disc

Preoperative and postoperative magnetic resonance imaging (MRI) of the lumbar spine was performed on 41 patients treated either microsurgically or with percutaneous nucleotomy for lumbar disc herniation. On the first postoperative day, MRI revealed an edematous mass effect at the level of surgery in 25 (61%) patients. The mass effect caused compression of the anterior dural sac mimicking preoperative disc herniation. After the follow-up of 6 months, the mass effect had disappeared in all patients, and the MRI finding in the operated disc space was that of a prolapse in six (15%) patients and that of a protrusion in 16 (39%) patients. Postoperative scarring was detected in 23 (56%) patients. The amount of the epidural scar tissue was significantly (p = 0.0002) associated with the extent of the early postoperative hemorrhagic changes detected in these patients with MRI. No association was observed between these MRI findings (mass effect, disc herniation, epidural scarring) and the clinical outcome of the patients.

Percutaneous nucleotomy in the treatment of lumbar disc herniation results after a mean follow-up of 2 years

We have evaluated the clinical outcome of 45 consecutive patients who underwent percutaneous nucleotomy for a single-level disc herniation. Included were 28 (62%) woman and 17 (38%) men, with a mean age of 46 years. The mean postoperative follow-up time was 2 years. Intra-operatively, disc herniation was graded as a protrusion in 23 (51%) patients and as a prolapse in 22 (49%) patients. During the follow-up, sciatic pain completely recovered or markedly diminished in 38 (84%) patients and 35 (78%) patients returned to work. The occupational outcome of the patients operated on for a protrusion was inferior to that of the patients operated on for a prolapse: only 22% of the patients who underwent surgery for a protrusion reported to manage their work well, while as many as 41% of those with a prolapse managed well (p = 0.04). Pre-operatively, clinical examination revealed segmental instability of the lumbar spine in 11 (24%) patients. There was a significant association between instability and unsatisfactory long-term outcome: of the patients with pre-operative instability, 45% were postoperatively retired or on sick leave because of the back, as compared to 15% of the 34 patients without instability (p = 0.03). Furthermore, patients with instability suffered from sciatica and low back pain significantly (p = 0.02) more often than those without instability. Surgical complications were infrequent. There were no nerve root lesions and no vascular injuries. Postoperative discitis developed in 2 (4%) patients. Of all patients, only 1 (2%) has been re-operated on for a recurrent disc.

Clinical instability of the lumbar spine after microdiscectomy

A total of 190 patients treated microsurgically for a virgin single level lumbar disc herniation were examined physically after a mean follow-up period of 3 years (range 21-68 months). Included were 99 (52%) men and 91 (48%) women with a mean age of 42 years. During the observation period, sciatica had completely recovered or markedly diminished in 172 (90%) patients, and 142 (75%) patients had returned to work. However, as many as 29% of the patients occasionally suffered from low back pain. Clinical examination revealed various signs and symptoms of segmental instability of the lumbar spine in 22% of the surgical patients. There was a significant association between postoperative instability and unsatisfactory long-term outcome: of the 42 patients with instability, 62% suffered from low back pain and 45% were on sick leave or retired because of the back, while the corresponding numbers for those patients without instability were 20% and 8%, respectively (p < 0.0001). Moreover, the mean value of the Oswestry index in instability patients was as high as 34% (SD 12), indicating moderate disability, whereas a significantly (p = 0.0001) lower Oswestry Index 16% (SD 13), indicating minimal disability, was detected in patients without instability.