Caution Regarding the Interpretation of Data

Data collection in the PMSI has an initial medico-economic purpose rather than an epidemiological one. The results of this surveillance should therefore be interpreted with caution.
Since not all lumbar disc herniations undergo surgery (due to the existence of symptomatic treatments such as corticosteroid injections, for example), the tracer does not allow for the calculation of the overall incidence of the condition but is limited to the incidence of cases that undergo surgery. The regional or departmental differences observed may thus reflect differences in the incidence of the condition (variable distributions of high-risk sectors and occupations across regions, variable frequency of high-risk endocrine conditions, etc.), but also, at times, heterogeneity in the coding practices for surgical procedures or differences in medical practice (choice of surgical treatment versus medical treatment) despite the existence of medical guidelines, or even differences in access to care.

The 6 procedure codes corresponding to the surgical treatment of a lumbar disc herniation (herniation removal or replacement of the intervertebral disc with a prosthesis) and the 3 procedure codes for surgical treatment of a disc herniation without specifying the spinal level, associated with a primary diagnosis of lumbar pathology consistent with a disc herniation, make it possible to identify, via standardized anonymous discharge summaries, all hospital stays in public or private facilities involving surgery for a lumbar disc herniation. Procedures involving the treatment of a recurrent disc herniation were not included, as the aim is to measure the incidence, i.e., the frequency of new cases.

Procedures for the treatment of lumbar disc herniation

• LFFA002: Excision of a herniated disc in the lumbar spine, via a posterior or posterolateral approach

• LFFA003: Excision of multiple herniated discs of the lumbar spine, via posterior or posterolateral approach

• LFFC002: Excision of a herniated disc of the spine, via retroperitoneoscopy

• LFFA011: Removal of a herniated disc in the spine, via laparotomy or lumbotomy

• LFFA010: Removal of a herniated disc in the spine with osteosynthesis and/or arthrodesis, via laparotomy or lumbotomy

• LFKA001: Replacement of a lumbar intervertebral disc with a total prosthesis, via laparotomy or lumbotomy – since 2012

Procedures for the treatment of a herniated disc, specific level of the spine not specified

• LHPH907: Excision of an intervertebral disc, via a transcutaneous approach with radiological guidance [Transcutaneous nucleotomy] – since 2007

• LHPH001: Excision of an intervertebral disc, percutaneously with radiological guidance [Percutaneous nucleotomy] – until 2007

• LHKA900: Replacement of an intervertebral disc with a prosthesis – until 2012

These procedure codes were selected from those listed in the Common Classification of Medical Procedures (CCAM) in collaboration with the experimental MSD surveillance network of the Pays de la Loire region and neurosurgeons and orthopedic surgeons in Angers. This list of procedures was updated in 2014.

Incidence rates (expressed per 100,000 person-years) are calculated for the entire population and for the 20–64 age group to approximate the ages of the working-age population. Departmental and regional incidence rates are age-standardized and stratified by sex. They are compared to national incidence rates using the comparative morbidity figure. Trend tests were conducted to interpret the temporal evolution of the incidence of surgical cases of lumbar disc herniation for each sex.

Calculation of incidence rates for surgical cases

based on PMSI data for the period under consideration. The denominators, broken down by age and/or sex like the numerators, correspond to estimates of the number of person-years for the year derived from INSEE’s localized population estimates. Person-year estimates are calculated using age in completed years, defined as the age in years at the time of the event or age at the last birthday.
If multiple hospital stays involving one of the 9 procedure codes are identified for the same patient (linking according to the recommendations of the Technical Agency for Hospitalization Information), in the same year, only the first is counted to calculate the annual incidence of lumbar disc herniation surgery, regardless of whether patients are affected at one or more intervertebral discs. Regional and departmental
incidence rates are standardized by the age of the French population in 2022.

Calculation of the Comparative Morbidity Figure

To compare each regional (or departmental) incidence rate standardized to the national incidence rate, the ratios between these two rates (Comparative Morbidity Figure) were calculated, along with their 95% confidence intervals.

CMFregion x = STDInc region x / NationalInc

Epidemiological Situation in France in 2022

The crude incidence rates of surgical cases of lumbar disc herniation, by age and sex, in France in 2022 are presented in Figure 1 and Table 1. The incidence rate rises sharply with age up to age 44 and then declines steadily in both men and women. The incidence rate is higher among men (34/100,000 versus 28/100,000 among women).

Trends in mainland France in incidence rates of surgical cases of lumbar disc herniation

The trend between 2006 and 2022 in national incidence rates (mainland France) for surgical treatment of lumbar disc herniation, by sex, for all ages, and for those aged 20–64, is shown in Figure 2. The incidence rate of surgical cases of lumbar disc herniation decreased significantly between 2006 and 2022, with an average annual decline of 3.8%, which was greater among men (-4.2%) than among women (-3.3%). Age-specific incidence rates were calculated for mainland France for the various years of surveillance (2006 to 2022), for the total population and then for each sex (Tables 2 to 4). Among both men and women and across all age groups, incidence rates declined steadily between 2006 and 2020 and have tended to plateau since 2020¹.

¹ Trends by age group not tested

Regional incidence rates in 2022

The incidence rate of surgical cases of lumbar disc herniation varies significantly from one region to another: standardized rates range from 51 per 100,000 person-years (PY) in Corsica to 6 per 100,000 PY in French Guiana. Regional incidence rates and their comparison with the national incidence rate, presented as a Comparative Morbidity Figure (CMF), are shown by sex for the entire population (Tables 5–6) and for the 20–64 age group (Tables 7–8).

Maps 1 and 2 show the CMF for each region, by sex, for all ages. Maps 3 and 4 show the CMF for each region, by sex, among those aged 20–64. The regions are divided into five CMF classes with thresholds (0.7 / 0.9 / 1.1 / 1.3) corresponding respectively to variations of -30%, -10%, +10%, and +30% relative to the national incidence rate.

Departmental incidence rates in 2022

The incidence rate of surgical cases of lumbar disc herniation also varies from one department to another. Departmental incidence rates and their comparison with the national incidence rate, expressed as a comparative morbidity figure (CMF), are presented for the entire population (Tables 9–10) and for the 20–64 age group (Tables 11–12). Maps 5 and 6 show the CMF for each department, by sex, for all ages. Maps 7 and 8 show the CMF for each department, by sex, among those aged 20–64. The departments are divided into five CMF categories with thresholds (0.7 / 0.9 / 1.1 / 1.3) corresponding respectively to variations of -30%, -10%, +10%, and +30% relative to the national incidence rate. For the same age structure, a large southern half of France, stretching from Charente-Maritime in the west to Bas-Rhin in the east, generally has higher incidence rates of surgical cases for lumbar disc herniation than the northern half (Maps 5–8). This same geographic difference is observed among people aged 20–64.

Epidemiological Situation in the Overseas Departments and Regions in 2022

Incidence data are presented for all overseas departments except Mayotte (due to the very low number of observed cases, which is incompatible with statistical confidentiality). In the overseas departments, the age-standardized incidence rates of surgical cases of lumbar disc herniation for the French population in the year of diagnosis are lower than in mainland France (Table 7). As in mainland France, incidence rates are higher among men than among women, except in French Guiana, which has very few surgical cases (Table 7).

Crude incidence rates were higher in 2022 among those aged 20–64 than in the population of all ages. This holds true for the various years of the follow-up (Tables 16, 18, 20, 22). Standardized incidence rates and their comparison to the national incidence rate, presented as a comparative morbidity figure (CMF), are shown for the entire population and for the 20–64 age group, which comprises the majority of the working-age population (Table 14). Among women, age-standardized incidence rates are four times lower in French Guiana and Martinique than for France as a whole. Among men, the age-standardized incidence rate is also five times lower in French Guiana compared to the national rate (CMF=0.13) (Tables 13 and 14).

Detailed results by DROM in 2022 and trends in incidence

• Guadeloupe – 971

In 2022, the standardized incidence rate of surgical cases of lumbar disc herniation among women in Guadeloupe is lower than that of women in France as a whole (20 per 100,000 women versus 28 per 100,000 women). Among men, the standardized incidence rate is close to the incidence rate for France (30 per 100,000 men versus 34 per 100,000 men) (Table 13).
Regardless of gender, incidence rates (crude rates) increased slightly over the entire study period in Guadeloupe between 2006 and 2009 despite a decrease in 2017, as observed for the overall French data. The same trends are observed in the general population and in the working-age population (Figure 3 and Table 15). Analysis of the age-adjusted trend in the general population shows a significant average annual increase between 2006 and 2022 among women (+1.5%) but a non-significant increase among men (+0.5%).

• Martinique – 972

Martinique is among the departments with the lowest standardized incidence rates of surgical cases of lumbar disc herniation in 2022 (Table 9) (13 per 100,000 men and 8 per 100,000 women), along with French Guiana and Maine-et-Loire.

The incidence (crude rates) of surgical cases of lumbar disc herniation decreased in Martinique between 2006 and 2022, among both men and women, and among those aged 20–64 as well as in the general population (Figure 4 and Table 16). Analysis of the age-adjusted trend in the general population shows an average annual decrease of -1.0% between 2006 and 2022 for both women and men (p<0.0001).

• French Guiana – 973

The age-standardized incidence rates of surgical cases of lumbar disc herniation in French Guiana in 2022 are among the lowest in France (4 per 100,000 men and 8 per 100,000 women), along with Martinique and Maine-et-Loire (Table 9).
Incidence rates were calculated for French Guiana between 2009 and 2022. Crude rates decreased among both men and women between 2009 and 2022 (Figure 5 and Table 17).

• Réunion – 974

The age-standardized incidence rates of surgical cases of lumbar disc herniation are lower in Réunion than in France as a whole (23 per 100,000 men and 16 per 100,000 women versus 34 per 100,000 men and 28 per 100,000 women) (Table 13).

Crude incidence rates were measured in Réunion between 2006 and 2022, among men and women, for those aged 20–64 and in the general population. A very sharp decrease in the incidence of surgical cases of lumbar disc herniation was observed from 2006 to 2008. Since 2008, the incidence has been gradually increasing again in Réunion among both men and women, but incidence rates remain low and below those of 2007 (Figure 6 and Table 18).

Caution regarding the interpretation of data

Data collection in the PMSI has an initial medico-economic purpose, not an epidemiological one. The results of this surveillance should therefore be interpreted with caution.
Since only a small proportion of herniated discs undergo surgery (due to the availability of medical treatments such as analgesics, oral anti-inflammatory drugs, or corticosteroid injections, for example), the tracer does not allow for the calculation of the incidence of the condition but is limited to the incidence of the condition treated surgically. Changes in the incidence of surgical cases may be influenced not only by changes in the incidence of the condition based on shifts in personal or occupational risk factors but also by changes in medical management recommendations or the availability of care, which itself varies from one geographic area to another.

The 20 procedure codes corresponding to the surgical treatment of a herniated disc (herniation removal or replacement of the intervertebral disc with a prosthesis) make it possible to identify, through standardized anonymous discharge summaries, all hospital stays—in public or private facilities—involving herniated disc surgery. Procedures involving the treatment of a recurrent herniated disc were not included, as the objective is to measure the incidence—that is, the frequency of new cases.

Procedures for the treatment of cervical disc herniation

• LDFA011: Excision of a herniated disc of the spine via anterior or anterolateral cervicotomy

• LDFA001: Excision of a herniated disc of the cervical spine, via posterior or posterolateral approach

• LDFA008: Excision of a herniated disc of the spine with osteosynthesis and/or arthrodesis, via anterior or anterolateral cervicotomy

• LDFA007: Excision of multiple herniated discs of the spine with osteosynthesis and/or arthrodesis, via anterior or anterolateral cervicotomy

• LDFA006: Excision of multiple herniated discs of the spine, via anterior or anterolateral cervicotomy

• LDKA900: Replacement of a cervical intervertebral disc with a prosthesis via cervicotomy – since 2012

Procedures for the treatment of thoracic disc herniation

• LEFA002: Excision of a disc herniation of the thoracic spine, via posterior or posterolateral approach

• LEFC002: Excision of a herniated disc in the spine, via thoracoscopy

• LEFA003: Excision of a herniated disc in the thoracic spine with osteosynthesis and/or arthrodesis, via posterior or posterolateral approach

• LEFA011: Excision of a herniated disc of the spine with osteosynthesis and/or arthrodesis, via thoracotomy

• LEFA013: Excision of a herniated disc of the spine, via thoracotomy

Procedures for the treatment of lumbar disc herniation

• LFFA002: Excision of a herniated disc in the lumbar spine, via a posterior or posterolateral approach

• LFFA003: Excision of multiple herniated discs of the lumbar spine, via posterior or posterolateral approach

• LFFC002: Removal of a herniated disc of the spine, via retroperitoneoscopy

• LFFA011: Removal of a herniated disc in the spine, via laparotomy or lumbotomy

• LFFA010: Removal of a herniated disc in the spine with osteosynthesis and/or arthrodesis, via laparotomy or lumbotomy

• LFKA001: Replacement of a lumbar intervertebral disc with a total prosthesis, via laparotomy or lumbotomy – since 2012

Procedures for the treatment of a herniated disc, specific level of the spine not specified

• LHPH907: Excision of an intervertebral disc, via a transcutaneous approach with radiological guidance [Transcutaneous nucleotomy] – since 2007

• LHPH001: Excision of an intervertebral disc, percutaneously with radiological guidance [Percutaneous nucleotomy] – until 2007

• LHKA900: Replacement of an intervertebral disc with a prosthesis – until 2012

These procedure codes were selected from those listed in the Common Classification of Medical Procedures. Surgical procedures for herniated disc repair without specification of the spinal level were assigned to one of the three herniation locations studied (cervical, thoracic, lumbar), based on the title of the primary diagnosis for the hospital stay, when this was possible.
Incidence rates (expressed per 100,000 person-years) were calculated for the entire population and for the 20–64 age group to approximate the ages of the working-age population. Trend
tests were conducted to interpret the temporal evolution of the incidence of surgical cases of herniated discs for each sex.

Calculation of incidence rates for surgical cases

The numerators are the numbers of incident cases (new cases) calculated from PMSI data for the period in question. The denominators, broken down by age and/or sex just like the numerators, correspond to estimates of the number of person-years for the year, derived from INSEE’s localized population estimates.
Estimates of the number of person-years are calculated using age in completed years, defined as the age in years at the time of the event or age on the last birthday.
If multiple hospital stays involving one of the 20 procedure codes are identified for the same patient (linking according to the recommendations of the Technical Agency for Hospitalization Information) in the same year, only the first one is counted to calculate the annual incidence of surgical cases of herniated discs, regardless of whether patients are affected at the level of one or more intervertebral discs.

Epidemiological Situation in Metropolitan France in 2022

A total of 26,358 people underwent surgery for a herniated disc in 2022, including 13,888 (53%) men.

Source: SNDS – PMSI-MCO (ATIH)
Analysis by Santé publique France – November
2023*Including cases where the specific location on the spine could not be determined.

Lumbar disc herniations accounted for the vast majority of cases, while cervical disc herniations accounted for 18% of cases in men and 22% of cases in women. Thoracic disc herniations accounted for less than 1% of cases for both sexes.
The incidence rates of surgical cases of disc herniation, by age and sex, in mainland France in 2022 are presented in Figure 1 and Table 1.
The incidence rate of surgical cases of disc herniation in 2022 in the general population is 42 per 100,000 person-years (PY) among men and 36 per 100,000 PY among women. These rates are higher for the 20–64 age group (62 per 100,000 PA among men and 54 per 100,000 PA among women).
The incidence of surgical cases of herniated discs is highest between the ages of 35 and 59 for both sexes. The incidence (combined men and women) increases up to age 49 and then gradually decreases.

Trends in incidence rates (mainland France) of surgical cases of herniated discs

The number of patients undergoing surgery for a herniated disc each year between 2006 and 2022 is presented for each spinal segment and for each sex (Table 0).
The trend between 2006 and 2022 in national incidence rates of surgical cases of herniated discs, by sex, for all ages combined, and for those aged 20–64, is shown in Figure 2.
The incidence rate of surgical cases of herniated discs in the overall French population decreased significantly between 2006 and 2022, with an average annual decline of 3.4% (a similar decline among those aged 20–64). This decrease applied to both men and women, with an average annual decline of 4.0% and 2.8%, respectively (similar declines among those aged 20–64). Age-specific incidence rates were calculated for mainland France for the various years of surveillance (2006 to 2022), for the total population and then for each sex (Tables 2 to 4). Among both men and women and across all age groups, incidence rates decreased over the ^period1.

¹ Trends by age group not tested.